From 4266129964b8238526936d723de65b419d8069c6 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 31 May 2011 16:27:44 -0300 Subject: [media] DocBook: Move all media docbook stuff into its own directory This patch addresses several issues pointed by Randy Dunlap at changeset ece722c: - In the generated index.html file, "media" is listed first, but it should be listed in alphabetical order, not first. - The generated files are (hidden) in .tmpmedia/ - The link from the top-level index.html file to "media" is to media/index.html, but the file is actually in .tmpmedia/media/index.html - Please build docs with and without using "O=builddir" and test that. - Would it be possible for media to have its own Makefile instead of merging into this one? Due to the way cleandocs target works, I had to rename the media DocBook to media_api, otherwise cleandocs would remove the /media directory. Thanks-to: Randy Dunlap Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/.gitignore | 1 + Documentation/DocBook/media/v4l/bayer.pdf | Bin 0 -> 12116 bytes Documentation/DocBook/media/v4l/bayer.png | Bin 0 -> 9725 bytes Documentation/DocBook/media/v4l/biblio.xml | 188 ++ Documentation/DocBook/media/v4l/capture.c.xml | 659 +++++ Documentation/DocBook/media/v4l/common.xml | 1197 +++++++++ Documentation/DocBook/media/v4l/compat.xml | 2500 +++++++++++++++++++ Documentation/DocBook/media/v4l/controls.xml | 2103 ++++++++++++++++ Documentation/DocBook/media/v4l/crop.gif | Bin 0 -> 5967 bytes Documentation/DocBook/media/v4l/crop.pdf | Bin 0 -> 5846 bytes Documentation/DocBook/media/v4l/dev-capture.xml | 118 + Documentation/DocBook/media/v4l/dev-codec.xml | 26 + Documentation/DocBook/media/v4l/dev-effect.xml | 25 + Documentation/DocBook/media/v4l/dev-event.xml | 31 + Documentation/DocBook/media/v4l/dev-osd.xml | 164 ++ Documentation/DocBook/media/v4l/dev-output.xml | 114 + Documentation/DocBook/media/v4l/dev-overlay.xml | 379 +++ Documentation/DocBook/media/v4l/dev-radio.xml | 57 + Documentation/DocBook/media/v4l/dev-raw-vbi.xml | 347 +++ Documentation/DocBook/media/v4l/dev-rds.xml | 204 ++ Documentation/DocBook/media/v4l/dev-sliced-vbi.xml | 708 ++++++ Documentation/DocBook/media/v4l/dev-subdev.xml | 313 +++ Documentation/DocBook/media/v4l/dev-teletext.xml | 37 + Documentation/DocBook/media/v4l/driver.xml | 208 ++ Documentation/DocBook/media/v4l/fdl-appendix.xml | 671 +++++ Documentation/DocBook/media/v4l/fieldseq_bt.gif | Bin 0 -> 25430 bytes Documentation/DocBook/media/v4l/fieldseq_bt.pdf | Bin 0 -> 9185 bytes Documentation/DocBook/media/v4l/fieldseq_tb.gif | Bin 0 -> 25323 bytes Documentation/DocBook/media/v4l/fieldseq_tb.pdf | Bin 0 -> 9173 bytes Documentation/DocBook/media/v4l/func-close.xml | 70 + Documentation/DocBook/media/v4l/func-ioctl.xml | 145 ++ Documentation/DocBook/media/v4l/func-mmap.xml | 191 ++ Documentation/DocBook/media/v4l/func-munmap.xml | 84 + Documentation/DocBook/media/v4l/func-open.xml | 121 + Documentation/DocBook/media/v4l/func-poll.xml | 127 + Documentation/DocBook/media/v4l/func-read.xml | 189 ++ Documentation/DocBook/media/v4l/func-select.xml | 138 ++ Documentation/DocBook/media/v4l/func-write.xml | 136 ++ Documentation/DocBook/media/v4l/io.xml | 1265 ++++++++++ Documentation/DocBook/media/v4l/keytable.c.xml | 172 ++ Documentation/DocBook/media/v4l/libv4l.xml | 167 ++ .../DocBook/media/v4l/lirc_device_interface.xml | 251 ++ .../DocBook/media/v4l/media-controller.xml | 89 + .../DocBook/media/v4l/media-func-close.xml | 59 + .../DocBook/media/v4l/media-func-ioctl.xml | 116 + .../DocBook/media/v4l/media-func-open.xml | 94 + .../DocBook/media/v4l/media-ioc-device-info.xml | 133 + .../DocBook/media/v4l/media-ioc-enum-entities.xml | 308 +++ .../DocBook/media/v4l/media-ioc-enum-links.xml | 207 ++ .../DocBook/media/v4l/media-ioc-setup-link.xml | 93 + Documentation/DocBook/media/v4l/nv12mt.gif | Bin 0 -> 2108 bytes Documentation/DocBook/media/v4l/nv12mt_example.gif | Bin 0 -> 6858 bytes Documentation/DocBook/media/v4l/pipeline.pdf | Bin 0 -> 20276 bytes Documentation/DocBook/media/v4l/pipeline.png | Bin 0 -> 12130 bytes Documentation/DocBook/media/v4l/pixfmt-grey.xml | 70 + Documentation/DocBook/media/v4l/pixfmt-m420.xml | 147 ++ Documentation/DocBook/media/v4l/pixfmt-nv12.xml | 151 ++ Documentation/DocBook/media/v4l/pixfmt-nv12m.xml | 154 ++ Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml | 74 + Documentation/DocBook/media/v4l/pixfmt-nv16.xml | 174 ++ .../DocBook/media/v4l/pixfmt-packed-rgb.xml | 940 +++++++ .../DocBook/media/v4l/pixfmt-packed-yuv.xml | 244 ++ Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml | 91 + Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml | 75 + Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml | 75 + Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml | 75 + Documentation/DocBook/media/v4l/pixfmt-srggb10.xml | 90 + Documentation/DocBook/media/v4l/pixfmt-srggb12.xml | 90 + Documentation/DocBook/media/v4l/pixfmt-srggb8.xml | 67 + Documentation/DocBook/media/v4l/pixfmt-uyvy.xml | 128 + Documentation/DocBook/media/v4l/pixfmt-vyuy.xml | 128 + Documentation/DocBook/media/v4l/pixfmt-y10.xml | 79 + Documentation/DocBook/media/v4l/pixfmt-y10b.xml | 43 + Documentation/DocBook/media/v4l/pixfmt-y12.xml | 79 + Documentation/DocBook/media/v4l/pixfmt-y16.xml | 89 + Documentation/DocBook/media/v4l/pixfmt-y41p.xml | 157 ++ Documentation/DocBook/media/v4l/pixfmt-yuv410.xml | 141 ++ Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml | 155 ++ Documentation/DocBook/media/v4l/pixfmt-yuv420.xml | 157 ++ Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml | 162 ++ Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml | 161 ++ Documentation/DocBook/media/v4l/pixfmt-yuyv.xml | 128 + Documentation/DocBook/media/v4l/pixfmt-yvyu.xml | 128 + Documentation/DocBook/media/v4l/pixfmt.xml | 951 ++++++++ Documentation/DocBook/media/v4l/planar-apis.xml | 62 + .../DocBook/media/v4l/remote_controllers.xml | 177 ++ Documentation/DocBook/media/v4l/subdev-formats.xml | 2572 ++++++++++++++++++++ Documentation/DocBook/media/v4l/v4l2.xml | 539 ++++ Documentation/DocBook/media/v4l/v4l2grab.c.xml | 164 ++ Documentation/DocBook/media/v4l/vbi_525.gif | Bin 0 -> 4741 bytes Documentation/DocBook/media/v4l/vbi_525.pdf | Bin 0 -> 3395 bytes Documentation/DocBook/media/v4l/vbi_625.gif | Bin 0 -> 5095 bytes Documentation/DocBook/media/v4l/vbi_625.pdf | Bin 0 -> 3683 bytes Documentation/DocBook/media/v4l/vbi_hsync.gif | Bin 0 -> 2400 bytes Documentation/DocBook/media/v4l/vbi_hsync.pdf | Bin 0 -> 7405 bytes Documentation/DocBook/media/v4l/vidioc-cropcap.xml | 174 ++ .../DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml | 275 +++ .../DocBook/media/v4l/vidioc-dbg-g-register.xml | 275 +++ Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 131 + .../DocBook/media/v4l/vidioc-encoder-cmd.xml | 204 ++ .../DocBook/media/v4l/vidioc-enum-dv-presets.xml | 238 ++ .../DocBook/media/v4l/vidioc-enum-fmt.xml | 166 ++ .../media/v4l/vidioc-enum-frameintervals.xml | 270 ++ .../DocBook/media/v4l/vidioc-enum-framesizes.xml | 282 +++ .../DocBook/media/v4l/vidioc-enumaudio.xml | 86 + .../DocBook/media/v4l/vidioc-enumaudioout.xml | 89 + .../DocBook/media/v4l/vidioc-enuminput.xml | 321 +++ .../DocBook/media/v4l/vidioc-enumoutput.xml | 206 ++ Documentation/DocBook/media/v4l/vidioc-enumstd.xml | 391 +++ Documentation/DocBook/media/v4l/vidioc-g-audio.xml | 188 ++ .../DocBook/media/v4l/vidioc-g-audioout.xml | 154 ++ Documentation/DocBook/media/v4l/vidioc-g-crop.xml | 143 ++ Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml | 130 + .../DocBook/media/v4l/vidioc-g-dv-preset.xml | 110 + .../DocBook/media/v4l/vidioc-g-dv-timings.xml | 223 ++ .../DocBook/media/v4l/vidioc-g-enc-index.xml | 213 ++ .../DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 307 +++ Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml | 473 ++++ Documentation/DocBook/media/v4l/vidioc-g-fmt.xml | 212 ++ .../DocBook/media/v4l/vidioc-g-frequency.xml | 145 ++ Documentation/DocBook/media/v4l/vidioc-g-input.xml | 100 + .../DocBook/media/v4l/vidioc-g-jpegcomp.xml | 180 ++ .../DocBook/media/v4l/vidioc-g-modulator.xml | 246 ++ .../DocBook/media/v4l/vidioc-g-output.xml | 100 + Documentation/DocBook/media/v4l/vidioc-g-parm.xml | 332 +++ .../DocBook/media/v4l/vidioc-g-priority.xml | 144 ++ .../DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml | 264 ++ Documentation/DocBook/media/v4l/vidioc-g-std.xml | 105 + Documentation/DocBook/media/v4l/vidioc-g-tuner.xml | 535 ++++ .../DocBook/media/v4l/vidioc-log-status.xml | 58 + Documentation/DocBook/media/v4l/vidioc-overlay.xml | 83 + Documentation/DocBook/media/v4l/vidioc-qbuf.xml | 194 ++ .../DocBook/media/v4l/vidioc-query-dv-preset.xml | 87 + .../DocBook/media/v4l/vidioc-querybuf.xml | 110 + .../DocBook/media/v4l/vidioc-querycap.xml | 303 +++ .../DocBook/media/v4l/vidioc-queryctrl.xml | 434 ++++ .../DocBook/media/v4l/vidioc-querystd.xml | 89 + Documentation/DocBook/media/v4l/vidioc-reqbufs.xml | 150 ++ .../DocBook/media/v4l/vidioc-s-hw-freq-seek.xml | 135 + .../DocBook/media/v4l/vidioc-streamon.xml | 115 + .../v4l/vidioc-subdev-enum-frame-interval.xml | 152 ++ .../media/v4l/vidioc-subdev-enum-frame-size.xml | 154 ++ .../media/v4l/vidioc-subdev-enum-mbus-code.xml | 119 + .../DocBook/media/v4l/vidioc-subdev-g-crop.xml | 155 ++ .../DocBook/media/v4l/vidioc-subdev-g-fmt.xml | 180 ++ .../media/v4l/vidioc-subdev-g-frame-interval.xml | 141 ++ .../DocBook/media/v4l/vidioc-subscribe-event.xml | 133 + 147 files changed, 33126 insertions(+) create mode 100644 Documentation/DocBook/media/v4l/.gitignore create mode 100644 Documentation/DocBook/media/v4l/bayer.pdf create mode 100644 Documentation/DocBook/media/v4l/bayer.png create mode 100644 Documentation/DocBook/media/v4l/biblio.xml create mode 100644 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mode 100644 index 00000000000..afc8a0dd260 --- /dev/null +++ b/Documentation/DocBook/media/v4l/biblio.xml @@ -0,0 +1,188 @@ + + References + + + EIA 608-B + + Electronic Industries Alliance (http://www.eia.org) + + EIA 608-B "Recommended Practice for Line 21 Data +Service" + + + + EN 300 294 + + European Telecommunication Standards Institute +(http://www.etsi.org) + + EN 300 294 "625-line television Wide Screen Signalling +(WSS)" + + + + ETS 300 231 + + European Telecommunication Standards Institute +(http://www.etsi.org) + + ETS 300 231 "Specification of the domestic video +Programme Delivery Control system (PDC)" + + + + ETS 300 706 + + European Telecommunication Standards Institute +(http://www.etsi.org) + + ETS 300 706 "Enhanced Teletext specification" + + + + ISO 13818-1 + + International Telecommunication Union (http://www.itu.ch), International +Organisation for Standardisation (http://www.iso.ch) + + ITU-T Rec. H.222.0 | ISO/IEC 13818-1 "Information +technology — Generic coding of moving pictures and associated +audio information: Systems" + + + + ISO 13818-2 + + International Telecommunication Union (http://www.itu.ch), International +Organisation for Standardisation (http://www.iso.ch) + + ITU-T Rec. H.262 | ISO/IEC 13818-2 "Information +technology — Generic coding of moving pictures and associated +audio information: Video" + + + + ITU BT.470 + + International Telecommunication Union (http://www.itu.ch) + + ITU-R Recommendation BT.470-6 "Conventional Television +Systems" + + + + ITU BT.601 + + International Telecommunication Union (http://www.itu.ch) + + ITU-R Recommendation BT.601-5 "Studio Encoding Parameters +of Digital Television for Standard 4:3 and Wide-Screen 16:9 Aspect +Ratios" + + + + ITU BT.653 + + International Telecommunication Union (http://www.itu.ch) + + ITU-R Recommendation BT.653-3 "Teletext systems" + + + + ITU BT.709 + + International Telecommunication Union (http://www.itu.ch) + + ITU-R Recommendation BT.709-5 "Parameter values for the +HDTV standards for production and international programme +exchange" + + + + ITU BT.1119 + + International Telecommunication Union (http://www.itu.ch) + + ITU-R Recommendation BT.1119 "625-line +television Wide Screen Signalling (WSS)" + + + + JFIF + + Independent JPEG Group (http://www.ijg.org) + + JPEG File Interchange Format + Version 1.02 + + + + SMPTE 12M + + Society of Motion Picture and Television Engineers +(http://www.smpte.org) + + SMPTE 12M-1999 "Television, Audio and Film - Time and +Control Code" + + + + SMPTE 170M + + Society of Motion Picture and Television Engineers +(http://www.smpte.org) + + SMPTE 170M-1999 "Television - Composite Analog Video +Signal - NTSC for Studio Applications" + + + + SMPTE 240M + + Society of Motion Picture and Television Engineers +(http://www.smpte.org) + + SMPTE 240M-1999 "Television - Signal Parameters - +1125-Line High-Definition Production" + + + + EN 50067 + + European Committee for Electrotechnical Standardization +(http://www.cenelec.eu) + + Specification of the radio data system (RDS) for VHF/FM sound broadcasting +in the frequency range from 87,5 to 108,0 MHz + + + + NRSC-4 + + National Radio Systems Committee +(http://www.nrscstandards.org) + + NTSC-4: United States RBDS Standard + + + + + diff --git a/Documentation/DocBook/media/v4l/capture.c.xml b/Documentation/DocBook/media/v4l/capture.c.xml new file mode 100644 index 00000000000..1c5c49a2de5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/capture.c.xml @@ -0,0 +1,659 @@ + +/* + * V4L2 video capture example + * + * This program can be used and distributed without restrictions. + * + * This program is provided with the V4L2 API + * see http://linuxtv.org/docs.php for more information + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include <getopt.h> /* getopt_long() */ + +#include <fcntl.h> /* low-level i/o */ +#include <unistd.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <sys/ioctl.h> + +#include <linux/videodev2.h> + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +enum io_method { + IO_METHOD_READ, + IO_METHOD_MMAP, + IO_METHOD_USERPTR, +}; + +struct buffer { + void *start; + size_t length; +}; + +static char *dev_name; +static enum io_method io = IO_METHOD_MMAP; +static int fd = -1; +struct buffer *buffers; +static unsigned int n_buffers; +static int out_buf; +static int force_format; +static int frame_count = 70; + +static void errno_exit(const char *s) +{ + fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); + exit(EXIT_FAILURE); +} + +static int xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = ioctl(fh, request, arg); + } while (-1 == r && EINTR == errno); + + return r; +} + +static void process_image(const void *p, int size) +{ + if (out_buf) + fwrite(p, size, 1, stdout); + + fflush(stderr); + fprintf(stderr, "."); + fflush(stdout); +} + +static int read_frame(void) +{ + struct v4l2_buffer buf; + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + if (-1 == read(fd, buffers[0].start, buffers[0].length)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("read"); + } + } + + process_image(buffers[0].start, buffers[0].length); + break; + + case IO_METHOD_MMAP: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + assert(buf.index < n_buffers); + + process_image(buffers[buf.index].start, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + + case IO_METHOD_USERPTR: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + for (i = 0; i < n_buffers; ++i) + if (buf.m.userptr == (unsigned long)buffers[i].start + && buf.length == buffers[i].length) + break; + + assert(i < n_buffers); + + process_image((void *)buf.m.userptr, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + } + + return 1; +} + +static void mainloop(void) +{ + unsigned int count; + + count = frame_count; + + while (count-- > 0) { + for (;;) { + fd_set fds; + struct timeval tv; + int r; + + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + + if (-1 == r) { + if (EINTR == errno) + continue; + errno_exit("select"); + } + + if (0 == r) { + fprintf(stderr, "select timeout\n"); + exit(EXIT_FAILURE); + } + + if (read_frame()) + break; + /* EAGAIN - continue select loop. */ + } + } +} + +static void stop_capturing(void) +{ + enum v4l2_buf_type type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) + errno_exit("VIDIOC_STREAMOFF"); + break; + } +} + +static void start_capturing(void) +{ + unsigned int i; + enum v4l2_buf_type type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) { + struct v4l2_buffer buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) { + struct v4l2_buffer buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + buf.index = i; + buf.m.userptr = (unsigned long)buffers[i].start; + buf.length = buffers[i].length; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + } +} + +static void uninit_device(void) +{ + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + free(buffers[0].start); + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) + if (-1 == munmap(buffers[i].start, buffers[i].length)) + errno_exit("munmap"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) + free(buffers[i].start); + break; + } + + free(buffers); +} + +static void init_read(unsigned int buffer_size) +{ + buffers = calloc(1, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + buffers[0].length = buffer_size; + buffers[0].start = malloc(buffer_size); + + if (!buffers[0].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } +} + +static void init_mmap(void) +{ + struct v4l2_requestbuffers req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "memory mapping\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + if (req.count < 2) { + fprintf(stderr, "Insufficient buffer memory on %s\n", + dev_name); + exit(EXIT_FAILURE); + } + + buffers = calloc(req.count, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + struct v4l2_buffer buf; + + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf)) + errno_exit("VIDIOC_QUERYBUF"); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = + mmap(NULL /* start anywhere */, + buf.length, + PROT_READ | PROT_WRITE /* required */, + MAP_SHARED /* recommended */, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) + errno_exit("mmap"); + } +} + +static void init_userp(unsigned int buffer_size) +{ + struct v4l2_requestbuffers req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "user pointer i/o\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + buffers = calloc(4, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < 4; ++n_buffers) { + buffers[n_buffers].length = buffer_size; + buffers[n_buffers].start = malloc(buffer_size); + + if (!buffers[n_buffers].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + } +} + +static void init_device(void) +{ + struct v4l2_capability cap; + struct v4l2_cropcap cropcap; + struct v4l2_crop crop; + struct v4l2_format fmt; + unsigned int min; + + if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) { + if (EINVAL == errno) { + fprintf(stderr, "%s is no V4L2 device\n", + dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_QUERYCAP"); + } + } + + if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) { + fprintf(stderr, "%s is no video capture device\n", + dev_name); + exit(EXIT_FAILURE); + } + + switch (io) { + case IO_METHOD_READ: + if (!(cap.capabilities & V4L2_CAP_READWRITE)) { + fprintf(stderr, "%s does not support read i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + if (!(cap.capabilities & V4L2_CAP_STREAMING)) { + fprintf(stderr, "%s does not support streaming i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + } + + + /* Select video input, video standard and tune here. */ + + + CLEAR(cropcap); + + cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) { + crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + crop.c = cropcap.defrect; /* reset to default */ + + if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) { + switch (errno) { + case EINVAL: + /* Cropping not supported. */ + break; + default: + /* Errors ignored. */ + break; + } + } + } else { + /* Errors ignored. */ + } + + + CLEAR(fmt); + + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (force_format) { + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + + if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt)) + errno_exit("VIDIOC_S_FMT"); + + /* Note VIDIOC_S_FMT may change width and height. */ + } else { + /* Preserve original settings as set by v4l2-ctl for example */ + if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt)) + errno_exit("VIDIOC_G_FMT"); + } + + /* Buggy driver paranoia. */ + min = fmt.fmt.pix.width * 2; + if (fmt.fmt.pix.bytesperline < min) + fmt.fmt.pix.bytesperline = min; + min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height; + if (fmt.fmt.pix.sizeimage < min) + fmt.fmt.pix.sizeimage = min; + + switch (io) { + case IO_METHOD_READ: + init_read(fmt.fmt.pix.sizeimage); + break; + + case IO_METHOD_MMAP: + init_mmap(); + break; + + case IO_METHOD_USERPTR: + init_userp(fmt.fmt.pix.sizeimage); + break; + } +} + +static void close_device(void) +{ + if (-1 == close(fd)) + errno_exit("close"); + + fd = -1; +} + +static void open_device(void) +{ + struct stat st; + + if (-1 == stat(dev_name, &st)) { + fprintf(stderr, "Cannot identify '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + if (!S_ISCHR(st.st_mode)) { + fprintf(stderr, "%s is no device\n", dev_name); + exit(EXIT_FAILURE); + } + + fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0); + + if (-1 == fd) { + fprintf(stderr, "Cannot open '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +static void usage(FILE *fp, int argc, char **argv) +{ + fprintf(fp, + "Usage: %s [options]\n\n" + "Version 1.3\n" + "Options:\n" + "-d | --device name Video device name [%s]\n" + "-h | --help Print this message\n" + "-m | --mmap Use memory mapped buffers [default]\n" + "-r | --read Use read() calls\n" + "-u | --userp Use application allocated buffers\n" + "-o | --output Outputs stream to stdout\n" + "-f | --format Force format to 640x480 YUYV\n" + "-c | --count Number of frames to grab [%i]\n" + "", + argv[0], dev_name, frame_count); +} + +static const char short_options[] = "d:hmruofc:"; + +static const struct option +long_options[] = { + { "device", required_argument, NULL, 'd' }, + { "help", no_argument, NULL, 'h' }, + { "mmap", no_argument, NULL, 'm' }, + { "read", no_argument, NULL, 'r' }, + { "userp", no_argument, NULL, 'u' }, + { "output", no_argument, NULL, 'o' }, + { "format", no_argument, NULL, 'f' }, + { "count", required_argument, NULL, 'c' }, + { 0, 0, 0, 0 } +}; + +int main(int argc, char **argv) +{ + dev_name = "/dev/video0"; + + for (;;) { + int idx; + int c; + + c = getopt_long(argc, argv, + short_options, long_options, &idx); + + if (-1 == c) + break; + + switch (c) { + case 0: /* getopt_long() flag */ + break; + + case 'd': + dev_name = optarg; + break; + + case 'h': + usage(stdout, argc, argv); + exit(EXIT_SUCCESS); + + case 'm': + io = IO_METHOD_MMAP; + break; + + case 'r': + io = IO_METHOD_READ; + break; + + case 'u': + io = IO_METHOD_USERPTR; + break; + + case 'o': + out_buf++; + break; + + case 'f': + force_format++; + break; + + case 'c': + errno = 0; + frame_count = strtol(optarg, NULL, 0); + if (errno) + errno_exit(optarg); + break; + + default: + usage(stderr, argc, argv); + exit(EXIT_FAILURE); + } + } + + open_device(); + init_device(); + start_capturing(); + mainloop(); + stop_capturing(); + uninit_device(); + close_device(); + fprintf(stderr, "\n"); + return 0; +} + diff --git a/Documentation/DocBook/media/v4l/common.xml b/Documentation/DocBook/media/v4l/common.xml new file mode 100644 index 00000000000..9028721438d --- /dev/null +++ b/Documentation/DocBook/media/v4l/common.xml @@ -0,0 +1,1197 @@ + Common API Elements + + Programming a V4L2 device consists of these +steps: + + + + Opening the device + + + Changing device properties, selecting a video and audio +input, video standard, picture brightness a. o. + + + Negotiating a data format + + + Negotiating an input/output method + + + The actual input/output loop + + + Closing the device + + + + In practice most steps are optional and can be executed out of +order. It depends on the V4L2 device type, you can read about the +details in . In this chapter we will discuss +the basic concepts applicable to all devices. + +
+ Opening and Closing Devices + +
+ Device Naming + + V4L2 drivers are implemented as kernel modules, loaded +manually by the system administrator or automatically when a device is +first opened. The driver modules plug into the "videodev" kernel +module. It provides helper functions and a common application +interface specified in this document. + + Each driver thus loaded registers one or more device nodes +with major number 81 and a minor number between 0 and 255. Assigning +minor numbers to V4L2 devices is entirely up to the system administrator, +this is primarily intended to solve conflicts between devices. + Access permissions are associated with character +device special files, hence we must ensure device numbers cannot +change with the module load order. To this end minor numbers are no +longer automatically assigned by the "videodev" module as in V4L but +requested by the driver. The defaults will suffice for most people +unless two drivers compete for the same minor numbers. + The module options to select minor numbers are named +after the device special file with a "_nr" suffix. For example "video_nr" +for /dev/video video capture devices. The number is +an offset to the base minor number associated with the device type. + + In earlier versions of the V4L2 API the module options +where named after the device special file with a "unit_" prefix, expressing +the minor number itself, not an offset. Rationale for this change is unknown. +Lastly the naming and semantics are just a convention among driver writers, +the point to note is that minor numbers are not supposed to be hardcoded +into drivers. + When the driver supports multiple devices of the same +type more than one minor number can be assigned, separated by commas: + + +> insmod mydriver.o video_nr=0,1 radio_nr=0,1 + + + In /etc/modules.conf this may be +written as: + +alias char-major-81-0 mydriver +alias char-major-81-1 mydriver +alias char-major-81-64 mydriver +options mydriver video_nr=0,1 radio_nr=0,1 + + + + When an application attempts to open a device +special file with major number 81 and minor number 0, 1, or 64, load +"mydriver" (and the "videodev" module it depends upon). + + + Register the first two video capture devices with +minor number 0 and 1 (base number is 0), the first two radio device +with minor number 64 and 65 (base 64). + + + When no minor number is given as module +option the driver supplies a default. +recommends the base minor numbers to be used for the various device +types. Obviously minor numbers must be unique. When the number is +already in use the offending device will not be +registered. + + By convention system administrators create various +character device special files with these major and minor numbers in +the /dev directory. The names recommended for the +different V4L2 device types are listed in . + + + The creation of character special files (with +mknod) is a privileged operation and +devices cannot be opened by major and minor number. That means +applications cannot reliable scan for loaded or +installed drivers. The user must enter a device name, or the +application can try the conventional device names. + + Under the device filesystem (devfs) the minor number +options are ignored. V4L2 drivers (or by proxy the "videodev" module) +automatically create the required device files in the +/dev/v4l directory using the conventional device +names above. +
+ + + +
+ Multiple Opens + + In general, V4L2 devices can be opened more than once. +When this is supported by the driver, users can for example start a +"panel" application to change controls like brightness or audio +volume, while another application captures video and audio. In other words, panel +applications are comparable to an OSS or ALSA audio mixer application. +When a device supports multiple functions like capturing and overlay +simultaneously, multiple opens allow concurrent +use of the device by forked processes or specialized applications. + + Multiple opens are optional, although drivers should +permit at least concurrent accesses without data exchange, &ie; panel +applications. This implies &func-open; can return an &EBUSY; when the +device is already in use, as well as &func-ioctl; functions initiating +data exchange (namely the &VIDIOC-S-FMT; ioctl), and the &func-read; +and &func-write; functions. + + Mere opening a V4L2 device does not grant exclusive +access. + Drivers could recognize the +O_EXCL open flag. Presently this is not required, +so applications cannot know if it really works. + Initiating data exchange however assigns the right +to read or write the requested type of data, and to change related +properties, to this file descriptor. Applications can request +additional access privileges using the priority mechanism described in +. +
+ +
+ Shared Data Streams + + V4L2 drivers should not support multiple applications +reading or writing the same data stream on a device by copying +buffers, time multiplexing or similar means. This is better handled by +a proxy application in user space. When the driver supports stream +sharing anyway it must be implemented transparently. The V4L2 API does +not specify how conflicts are solved. +
+ +
+ Functions + + To open and close V4L2 devices applications use the +&func-open; and &func-close; function, respectively. Devices are +programmed using the &func-ioctl; function as explained in the +following sections. +
+
+ +
+ Querying Capabilities + + Because V4L2 covers a wide variety of devices not all +aspects of the API are equally applicable to all types of devices. +Furthermore devices of the same type have different capabilities and +this specification permits the omission of a few complicated and less +important parts of the API. + + The &VIDIOC-QUERYCAP; ioctl is available to check if the kernel +device is compatible with this specification, and to query the functions and I/O +methods supported by the device. Other features can be queried +by calling the respective ioctl, for example &VIDIOC-ENUMINPUT; +to learn about the number, types and names of video connectors on the +device. Although abstraction is a major objective of this API, the +ioctl also allows driver specific applications to reliable identify +the driver. + + All V4L2 drivers must support +VIDIOC_QUERYCAP. Applications should always call +this ioctl after opening the device. +
+ +
+ Application Priority + + When multiple applications share a device it may be +desirable to assign them different priorities. Contrary to the +traditional "rm -rf /" school of thought a video recording application +could for example block other applications from changing video +controls or switching the current TV channel. Another objective is to +permit low priority applications working in background, which can be +preempted by user controlled applications and automatically regain +control of the device at a later time. + + Since these features cannot be implemented entirely in user +space V4L2 defines the &VIDIOC-G-PRIORITY; and &VIDIOC-S-PRIORITY; +ioctls to request and query the access priority associate with a file +descriptor. Opening a device assigns a medium priority, compatible +with earlier versions of V4L2 and drivers not supporting these ioctls. +Applications requiring a different priority will usually call +VIDIOC_S_PRIORITY after verifying the device with +the &VIDIOC-QUERYCAP; ioctl. + + Ioctls changing driver properties, such as &VIDIOC-S-INPUT;, +return an &EBUSY; after another application obtained higher priority. +An event mechanism to notify applications about asynchronous property +changes has been proposed but not added yet. +
+ +
+ Video Inputs and Outputs + + Video inputs and outputs are physical connectors of a +device. These can be for example RF connectors (antenna/cable), CVBS +a.k.a. Composite Video, S-Video or RGB connectors. Only video and VBI +capture devices have inputs, output devices have outputs, at least one +each. Radio devices have no video inputs or outputs. + + To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMINPUT; and &VIDIOC-ENUMOUTPUT; ioctl, respectively. The +&v4l2-input; returned by the VIDIOC_ENUMINPUT +ioctl also contains signal status information applicable when the +current video input is queried. + + The &VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; ioctl return the +index of the current video input or output. To select a different +input or output applications call the &VIDIOC-S-INPUT; and +&VIDIOC-S-OUTPUT; ioctl. Drivers must implement all the input ioctls +when the device has one or more inputs, all the output ioctls when the +device has one or more outputs. + + + + + Information about the current video input + + +&v4l2-input; input; +int index; + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +memset (&input, 0, sizeof (input)); +input.index = index; + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUMINPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", input.name); + + + + + Switching to the first video input + + +int index; + +index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-INPUT;, &index)) { + perror ("VIDIOC_S_INPUT"); + exit (EXIT_FAILURE); +} + + +
+ +
+ Audio Inputs and Outputs + + Audio inputs and outputs are physical connectors of a +device. Video capture devices have inputs, output devices have +outputs, zero or more each. Radio devices have no audio inputs or +outputs. They have exactly one tuner which in fact +is an audio source, but this API associates +tuners with video inputs or outputs only, and radio devices have +none of these. + Actually &v4l2-audio; ought to have a +tuner field like &v4l2-input;, not only +making the API more consistent but also permitting radio devices with +multiple tuners. + A connector on a TV card to loop back the received +audio signal to a sound card is not considered an audio output. + + Audio and video inputs and outputs are associated. Selecting +a video source also selects an audio source. This is most evident when +the video and audio source is a tuner. Further audio connectors can +combine with more than one video input or output. Assumed two +composite video inputs and two audio inputs exist, there may be up to +four valid combinations. The relation of video and audio connectors +is defined in the audioset field of the +respective &v4l2-input; or &v4l2-output;, where each bit represents +the index number, starting at zero, of one audio input or output. + + To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMAUDIO; and &VIDIOC-ENUMAUDOUT; ioctl, respectively. The +&v4l2-audio; returned by the VIDIOC_ENUMAUDIO ioctl +also contains signal status information applicable when the current +audio input is queried. + + The &VIDIOC-G-AUDIO; and &VIDIOC-G-AUDOUT; ioctl report +the current audio input and output, respectively. Note that, unlike +&VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; these ioctls return a structure +as VIDIOC_ENUMAUDIO and +VIDIOC_ENUMAUDOUT do, not just an index. + + To select an audio input and change its properties +applications call the &VIDIOC-S-AUDIO; ioctl. To select an audio +output (which presently has no changeable properties) applications +call the &VIDIOC-S-AUDOUT; ioctl. + + Drivers must implement all input ioctls when the device +has one or more inputs, all output ioctls when the device has one +or more outputs. When the device has any audio inputs or outputs the +driver must set the V4L2_CAP_AUDIO flag in the +&v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl. + + + Information about the current audio input + + +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); + +if (-1 == ioctl (fd, &VIDIOC-G-AUDIO;, &audio)) { + perror ("VIDIOC_G_AUDIO"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", audio.name); + + + + + Switching to the first audio input + + +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); /* clear audio.mode, audio.reserved */ + +audio.index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-AUDIO;, &audio)) { + perror ("VIDIOC_S_AUDIO"); + exit (EXIT_FAILURE); +} + + +
+ +
+ Tuners and Modulators + +
+ Tuners + + Video input devices can have one or more tuners +demodulating a RF signal. Each tuner is associated with one or more +video inputs, depending on the number of RF connectors on the tuner. +The type field of the respective +&v4l2-input; returned by the &VIDIOC-ENUMINPUT; ioctl is set to +V4L2_INPUT_TYPE_TUNER and its +tuner field contains the index number of +the tuner. + + Radio devices have exactly one tuner with index zero, no +video inputs. + + To query and change tuner properties applications use the +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; ioctl, respectively. The +&v4l2-tuner; returned by VIDIOC_G_TUNER also +contains signal status information applicable when the tuner of the +current video input, or a radio tuner is queried. Note that +VIDIOC_S_TUNER does not switch the current tuner, +when there is more than one at all. The tuner is solely determined by +the current video input. Drivers must support both ioctls and set the +V4L2_CAP_TUNER flag in the &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl when the device has one or +more tuners. +
+ +
+ Modulators + + Video output devices can have one or more modulators, uh, +modulating a video signal for radiation or connection to the antenna +input of a TV set or video recorder. Each modulator is associated with +one or more video outputs, depending on the number of RF connectors on +the modulator. The type field of the +respective &v4l2-output; returned by the &VIDIOC-ENUMOUTPUT; ioctl is +set to V4L2_OUTPUT_TYPE_MODULATOR and its +modulator field contains the index number +of the modulator. This specification does not define radio output +devices. + + To query and change modulator properties applications use +the &VIDIOC-G-MODULATOR; and &VIDIOC-S-MODULATOR; ioctl. Note that +VIDIOC_S_MODULATOR does not switch the current +modulator, when there is more than one at all. The modulator is solely +determined by the current video output. Drivers must support both +ioctls and set the V4L2_CAP_MODULATOR flag in +the &v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl when the +device has one or more modulators. +
+ +
+ Radio Frequency + + To get and set the tuner or modulator radio frequency +applications use the &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY; +ioctl which both take a pointer to a &v4l2-frequency;. These ioctls +are used for TV and radio devices alike. Drivers must support both +ioctls when the tuner or modulator ioctls are supported, or +when the device is a radio device. +
+
+ +
+ Video Standards + + Video devices typically support one or more different video +standards or variations of standards. Each video input and output may +support another set of standards. This set is reported by the +std field of &v4l2-input; and +&v4l2-output; returned by the &VIDIOC-ENUMINPUT; and +&VIDIOC-ENUMOUTPUT; ioctl, respectively. + + V4L2 defines one bit for each analog video standard +currently in use worldwide, and sets aside bits for driver defined +standards, ⪚ hybrid standards to watch NTSC video tapes on PAL TVs +and vice versa. Applications can use the predefined bits to select a +particular standard, although presenting the user a menu of supported +standards is preferred. To enumerate and query the attributes of the +supported standards applications use the &VIDIOC-ENUMSTD; ioctl. + + Many of the defined standards are actually just variations +of a few major standards. The hardware may in fact not distinguish +between them, or do so internal and switch automatically. Therefore +enumerated standards also contain sets of one or more standard +bits. + + Assume a hypothetic tuner capable of demodulating B/PAL, +G/PAL and I/PAL signals. The first enumerated standard is a set of B +and G/PAL, switched automatically depending on the selected radio +frequency in UHF or VHF band. Enumeration gives a "PAL-B/G" or "PAL-I" +choice. Similar a Composite input may collapse standards, enumerating +"PAL-B/G/H/I", "NTSC-M" and "SECAM-D/K". + Some users are already confused by technical terms PAL, +NTSC and SECAM. There is no point asking them to distinguish between +B, G, D, or K when the software or hardware can do that +automatically. + + + To query and select the standard used by the current video +input or output applications call the &VIDIOC-G-STD; and +&VIDIOC-S-STD; ioctl, respectively. The received +standard can be sensed with the &VIDIOC-QUERYSTD; ioctl. Note parameter of all these ioctls is a pointer to a &v4l2-std-id; type (a standard set), not an index into the standard enumeration. + An alternative to the current scheme is to use pointers +to indices as arguments of VIDIOC_G_STD and +VIDIOC_S_STD, the &v4l2-input; and +&v4l2-output; std field would be a set of +indices like audioset. + Indices are consistent with the rest of the API +and identify the standard unambiguously. In the present scheme of +things an enumerated standard is looked up by &v4l2-std-id;. Now the +standards supported by the inputs of a device can overlap. Just +assume the tuner and composite input in the example above both +exist on a device. An enumeration of "PAL-B/G", "PAL-H/I" suggests +a choice which does not exist. We cannot merge or omit sets, because +applications would be unable to find the standards reported by +VIDIOC_G_STD. That leaves separate enumerations +for each input. Also selecting a standard by &v4l2-std-id; can be +ambiguous. Advantage of this method is that applications need not +identify the standard indirectly, after enumerating.So in +summary, the lookup itself is unavoidable. The difference is only +whether the lookup is necessary to find an enumerated standard or to +switch to a standard by &v4l2-std-id;. + Drivers must implement all video standard ioctls +when the device has one or more video inputs or outputs. + + Special rules apply to USB cameras where the notion of video +standards makes little sense. More generally any capture device, +output devices accordingly, which is + + incapable of capturing fields or frames at the nominal +rate of the video standard, or + + + where timestamps refer +to the instant the field or frame was received by the driver, not the +capture time, or + + + where sequence numbers +refer to the frames received by the driver, not the captured +frames. + + Here the driver shall set the +std field of &v4l2-input; and &v4l2-output; +to zero, the VIDIOC_G_STD, +VIDIOC_S_STD, +VIDIOC_QUERYSTD and +VIDIOC_ENUMSTD ioctls shall return the +&EINVAL;. + See for a rationale. Probably +even USB cameras follow some well known video standard. It might have +been better to explicitly indicate elsewhere if a device cannot live +up to normal expectations, instead of this exception. + + + + Information about the current video standard + + +&v4l2-std-id; std_id; +&v4l2-standard; standard; + +if (-1 == ioctl (fd, &VIDIOC-G-STD;, &std_id)) { + /* Note when VIDIOC_ENUMSTD always returns EINVAL this + is no video device or it falls under the USB exception, + and VIDIOC_G_STD returning EINVAL is no error. */ + + perror ("VIDIOC_G_STD"); + exit (EXIT_FAILURE); +} + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & std_id) { + printf ("Current video standard: %s\n", standard.name); + exit (EXIT_SUCCESS); + } + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno == EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + + + + + Listing the video standards supported by the current +input + + +&v4l2-input; input; +&v4l2-standard; standard; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input %s supports:\n", input.name); + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & input.std) + printf ("%s\n", standard.name); + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno != EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + + + + + Selecting a new video standard + + +&v4l2-input; input; +&v4l2-std-id; std_id; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +if (0 == (input.std & V4L2_STD_PAL_BG)) { + fprintf (stderr, "Oops. B/G PAL is not supported.\n"); + exit (EXIT_FAILURE); +} + +/* Note this is also supposed to work when only B + or G/PAL is supported. */ + +std_id = V4L2_STD_PAL_BG; + +if (-1 == ioctl (fd, &VIDIOC-S-STD;, &std_id)) { + perror ("VIDIOC_S_STD"); + exit (EXIT_FAILURE); +} + + +
+ Digital Video (DV) Timings + + The video standards discussed so far has been dealing with Analog TV and the +corresponding video timings. Today there are many more different hardware interfaces +such as High Definition TV interfaces (HDMI), VGA, DVI connectors etc., that carry +video signals and there is a need to extend the API to select the video timings +for these interfaces. Since it is not possible to extend the &v4l2-std-id; due to +the limited bits available, a new set of IOCTLs is added to set/get video timings at +the input and output: + + DV Presets: Digital Video (DV) presets. These are IDs representing a +video timing at the input/output. Presets are pre-defined timings implemented +by the hardware according to video standards. A __u32 data type is used to represent +a preset unlike the bit mask that is used in &v4l2-std-id; allowing future extensions +to support as many different presets as needed. + + + Custom DV Timings: This will allow applications to define more detailed +custom video timings for the interface. This includes parameters such as width, height, +polarities, frontporch, backporch etc. + + + + To enumerate and query the attributes of DV presets supported by a device, +applications use the &VIDIOC-ENUM-DV-PRESETS; ioctl. To get the current DV preset, +applications use the &VIDIOC-G-DV-PRESET; ioctl and to set a preset they use the +&VIDIOC-S-DV-PRESET; ioctl. + To set custom DV timings for the device, applications use the +&VIDIOC-S-DV-TIMINGS; ioctl and to get current custom DV timings they use the +&VIDIOC-G-DV-TIMINGS; ioctl. + Applications can make use of the and + flags to decide what ioctls are available to set the +video timings for the device. +
+
+ + &sub-controls; + +
+ Data Formats + +
+ Data Format Negotiation + + Different devices exchange different kinds of data with +applications, for example video images, raw or sliced VBI data, RDS +datagrams. Even within one kind many different formats are possible, +in particular an abundance of image formats. Although drivers must +provide a default and the selection persists across closing and +reopening a device, applications should always negotiate a data format +before engaging in data exchange. Negotiation means the application +asks for a particular format and the driver selects and reports the +best the hardware can do to satisfy the request. Of course +applications can also just query the current selection. + + A single mechanism exists to negotiate all data formats +using the aggregate &v4l2-format; and the &VIDIOC-G-FMT; and +&VIDIOC-S-FMT; ioctls. Additionally the &VIDIOC-TRY-FMT; ioctl can be +used to examine what the hardware could do, +without actually selecting a new data format. The data formats +supported by the V4L2 API are covered in the respective device section +in . For a closer look at image formats see +. + + The VIDIOC_S_FMT ioctl is a major +turning-point in the initialization sequence. Prior to this point +multiple panel applications can access the same device concurrently to +select the current input, change controls or modify other properties. +The first VIDIOC_S_FMT assigns a logical stream +(video data, VBI data etc.) exclusively to one file descriptor. + + Exclusive means no other application, more precisely no +other file descriptor, can grab this stream or change device +properties inconsistent with the negotiated parameters. A video +standard change for example, when the new standard uses a different +number of scan lines, can invalidate the selected image format. +Therefore only the file descriptor owning the stream can make +invalidating changes. Accordingly multiple file descriptors which +grabbed different logical streams prevent each other from interfering +with their settings. When for example video overlay is about to start +or already in progress, simultaneous video capturing may be restricted +to the same cropping and image size. + + When applications omit the +VIDIOC_S_FMT ioctl its locking side effects are +implied by the next step, the selection of an I/O method with the +&VIDIOC-REQBUFS; ioctl or implicit with the first &func-read; or +&func-write; call. + + Generally only one logical stream can be assigned to a +file descriptor, the exception being drivers permitting simultaneous +video capturing and overlay using the same file descriptor for +compatibility with V4L and earlier versions of V4L2. Switching the +logical stream or returning into "panel mode" is possible by closing +and reopening the device. Drivers may support a +switch using VIDIOC_S_FMT. + + All drivers exchanging data with +applications must support the VIDIOC_G_FMT and +VIDIOC_S_FMT ioctl. Implementation of the +VIDIOC_TRY_FMT is highly recommended but +optional. +
+ +
+ Image Format Enumeration + + Apart of the generic format negotiation functions +a special ioctl to enumerate all image formats supported by video +capture, overlay or output devices is available. + Enumerating formats an application has no a-priori +knowledge of (otherwise it could explicitly ask for them and need not +enumerate) seems useless, but there are applications serving as proxy +between drivers and the actual video applications for which this is +useful. + + + The &VIDIOC-ENUM-FMT; ioctl must be supported +by all drivers exchanging image data with applications. + + + Drivers are not supposed to convert image formats in +kernel space. They must enumerate only formats directly supported by +the hardware. If necessary driver writers should publish an example +conversion routine or library for integration into applications. + +
+
+ + &sub-planar-apis; + +
+ Image Cropping, Insertion and Scaling + + Some video capture devices can sample a subsection of the +picture and shrink or enlarge it to an image of arbitrary size. We +call these abilities cropping and scaling. Some video output devices +can scale an image up or down and insert it at an arbitrary scan line +and horizontal offset into a video signal. + + Applications can use the following API to select an area in +the video signal, query the default area and the hardware limits. +Despite their name, the &VIDIOC-CROPCAP;, &VIDIOC-G-CROP; +and &VIDIOC-S-CROP; ioctls apply to input as well as output +devices. + + Scaling requires a source and a target. On a video capture +or overlay device the source is the video signal, and the cropping +ioctls determine the area actually sampled. The target are images +read by the application or overlaid onto the graphics screen. Their +size (and position for an overlay) is negotiated with the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls. + + On a video output device the source are the images passed in +by the application, and their size is again negotiated with the +VIDIOC_G/S_FMT ioctls, or may be encoded in a +compressed video stream. The target is the video signal, and the +cropping ioctls determine the area where the images are +inserted. + + Source and target rectangles are defined even if the device +does not support scaling or the VIDIOC_G/S_CROP +ioctls. Their size (and position where applicable) will be fixed in +this case. All capture and output device must support the +VIDIOC_CROPCAP ioctl such that applications can +determine if scaling takes place. + +
+ Cropping Structures + +
+ Image Cropping, Insertion and Scaling + + + + + + + + + The cropping, insertion and scaling process + + +
+ + For capture devices the coordinates of the top left +corner, width and height of the area which can be sampled is given by +the bounds substructure of the +&v4l2-cropcap; returned by the VIDIOC_CROPCAP +ioctl. To support a wide range of hardware this specification does not +define an origin or units. However by convention drivers should +horizontally count unscaled samples relative to 0H (the leading edge +of the horizontal sync pulse, see ). +Vertically ITU-R line +numbers of the first field (, ), multiplied by two if the driver can capture both +fields. + + The top left corner, width and height of the source +rectangle, that is the area actually sampled, is given by &v4l2-crop; +using the same coordinate system as &v4l2-cropcap;. Applications can +use the VIDIOC_G_CROP and +VIDIOC_S_CROP ioctls to get and set this +rectangle. It must lie completely within the capture boundaries and +the driver may further adjust the requested size and/or position +according to hardware limitations. + + Each capture device has a default source rectangle, given +by the defrect substructure of +&v4l2-cropcap;. The center of this rectangle shall align with the +center of the active picture area of the video signal, and cover what +the driver writer considers the complete picture. Drivers shall reset +the source rectangle to the default when the driver is first loaded, +but not later. + + For output devices these structures and ioctls are used +accordingly, defining the target rectangle where +the images will be inserted into the video signal. + +
+ +
+ Scaling Adjustments + + Video hardware can have various cropping, insertion and +scaling limitations. It may only scale up or down, support only +discrete scaling factors, or have different scaling abilities in +horizontal and vertical direction. Also it may not support scaling at +all. At the same time the &v4l2-crop; rectangle may have to be +aligned, and both the source and target rectangles may have arbitrary +upper and lower size limits. In particular the maximum +width and height +in &v4l2-crop; may be smaller than the +&v4l2-cropcap;.bounds area. Therefore, as +usual, drivers are expected to adjust the requested parameters and +return the actual values selected. + + Applications can change the source or the target rectangle +first, as they may prefer a particular image size or a certain area in +the video signal. If the driver has to adjust both to satisfy hardware +limitations, the last requested rectangle shall take priority, and the +driver should preferably adjust the opposite one. The &VIDIOC-TRY-FMT; +ioctl however shall not change the driver state and therefore only +adjust the requested rectangle. + + Suppose scaling on a video capture device is restricted to +a factor 1:1 or 2:1 in either direction and the target image size must +be a multiple of 16 × 16 pixels. The source cropping +rectangle is set to defaults, which are also the upper limit in this +example, of 640 × 400 pixels at offset 0, 0. An +application requests an image size of 300 × 225 +pixels, assuming video will be scaled down from the "full picture" +accordingly. The driver sets the image size to the closest possible +values 304 × 224, then chooses the cropping rectangle +closest to the requested size, that is 608 × 224 +(224 × 2:1 would exceed the limit 400). The offset +0, 0 is still valid, thus unmodified. Given the default cropping +rectangle reported by VIDIOC_CROPCAP the +application can easily propose another offset to center the cropping +rectangle. + + Now the application may insist on covering an area using a +picture aspect ratio closer to the original request, so it asks for a +cropping rectangle of 608 × 456 pixels. The present +scaling factors limit cropping to 640 × 384, so the +driver returns the cropping size 608 × 384 and adjusts +the image size to closest possible 304 × 192. + +
+ +
+ Examples + + Source and target rectangles shall remain unchanged across +closing and reopening a device, such that piping data into or out of a +device will work without special preparations. More advanced +applications should ensure the parameters are suitable before starting +I/O. + + + Resetting the cropping parameters + + (A video capture device is assumed; change +V4L2_BUF_TYPE_VIDEO_CAPTURE for other +devices.) + + +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +crop.c = cropcap.defrect; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, &VIDIOC-S-CROP;, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} + + + + + Simple downscaling + + (A video capture device is assumed.) + + +&v4l2-cropcap; cropcap; +&v4l2-format; format; + +reset_cropping_parameters (); + +/* Scale down to 1/4 size of full picture. */ + +memset (&format, 0, sizeof (format)); /* defaults */ + +format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +format.fmt.pix.width = cropcap.defrect.width >> 1; +format.fmt.pix.height = cropcap.defrect.height >> 1; +format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + +if (-1 == ioctl (fd, &VIDIOC-S-FMT;, &format)) { + perror ("VIDIOC_S_FORMAT"); + exit (EXIT_FAILURE); +} + +/* We could check the actual image size now, the actual scaling factor + or if the driver can scale at all. */ + + + + + Selecting an output area + + +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; + +if (-1 == ioctl (fd, VIDIOC_CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); + +crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; +crop.c = cropcap.defrect; + +/* Scale the width and height to 50 % of their original size + and center the output. */ + +crop.c.width /= 2; +crop.c.height /= 2; +crop.c.left += crop.c.width / 2; +crop.c.top += crop.c.height / 2; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, VIDIOC_S_CROP, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} + + + + + Current scaling factor and pixel aspect + + (A video capture device is assumed.) + + +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; +&v4l2-format; format; +double hscale, vscale; +double aspect; +int dwidth, dheight; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-CROP;, &crop)) { + if (errno != EINVAL) { + perror ("VIDIOC_G_CROP"); + exit (EXIT_FAILURE); + } + + /* Cropping not supported. */ + crop.c = cropcap.defrect; +} + +memset (&format, 0, sizeof (format)); +format.fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-FMT;, &format)) { + perror ("VIDIOC_G_FMT"); + exit (EXIT_FAILURE); +} + +/* The scaling applied by the driver. */ + +hscale = format.fmt.pix.width / (double) crop.c.width; +vscale = format.fmt.pix.height / (double) crop.c.height; + +aspect = cropcap.pixelaspect.numerator / + (double) cropcap.pixelaspect.denominator; +aspect = aspect * hscale / vscale; + +/* Devices following ITU-R BT.601 do not capture + square pixels. For playback on a computer monitor + we should scale the images to this size. */ + +dwidth = format.fmt.pix.width / aspect; +dheight = format.fmt.pix.height; + + +
+
+ +
+ Streaming Parameters + + Streaming parameters are intended to optimize the video +capture process as well as I/O. Presently applications can request a +high quality capture mode with the &VIDIOC-S-PARM; ioctl. + + The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the &func-read; or &func-write;, which are not augmented by timestamps +or sequence counters, and to avoid unnecessary data copying. + + Finally these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function. + + To get and set the streaming parameters applications call +the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; ioctl, respectively. They take +a pointer to a &v4l2-streamparm;, which contains a union holding +separate parameters for input and output devices. + + These ioctls are optional, drivers need not implement +them. If so, they return the &EINVAL;. +
+ + diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml new file mode 100644 index 00000000000..9f7cd4f2579 --- /dev/null +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -0,0 +1,2500 @@ + Changes + + The following chapters document the evolution of the V4L2 API, +errata or extensions. They are also intended to help application and +driver writers to port or update their code. + +
+ Differences between V4L and V4L2 + + The Video For Linux API was first introduced in Linux 2.1 to +unify and replace various TV and radio device related interfaces, +developed independently by driver writers in prior years. Starting +with Linux 2.5 the much improved V4L2 API replaces the V4L API, +although existing drivers will continue to support V4L applications in +the future, either directly or through the V4L2 compatibility layer in +the videodev kernel module translating ioctls on +the fly. For a transition period not all drivers will support the V4L2 +API. + +
+ Opening and Closing Devices + + For compatibility reasons the character device file names +recommended for V4L2 video capture, overlay, radio and raw +vbi capture devices did not change from those used by V4L. They are +listed in and below in . + + The teletext devices (minor range 192-223) have been removed in +V4L2 and no longer exist. There is no hardware available anymore for handling +pure teletext. Instead raw or sliced VBI is used. + + The V4L videodev module automatically +assigns minor numbers to drivers in load order, depending on the +registered device type. We recommend that V4L2 drivers by default +register devices with the same numbers, but the system administrator +can assign arbitrary minor numbers using driver module options. The +major device number remains 81. + + + V4L Device Types, Names and Numbers + + + + Device Type + File Name + Minor Numbers + + + + + Video capture and overlay + /dev/video and +/dev/bttv0 According to +Documentation/devices.txt these should be symbolic links to +/dev/video0. Note the original bttv interface is +not compatible with V4L or V4L2. , +/dev/video0 to +/dev/video63 + 0-63 + + + Radio receiver + /dev/radio + According to +Documentation/devices.txt a symbolic link to +/dev/radio0. + , /dev/radio0 to +/dev/radio63 + 64-127 + + + Raw VBI capture + /dev/vbi, +/dev/vbi0 to +/dev/vbi31 + 224-255 + + + +
+ + V4L prohibits (or used to prohibit) multiple opens of a +device file. V4L2 drivers may support multiple +opens, see for details and consequences. + + V4L drivers respond to V4L2 ioctls with an &EINVAL;. The +compatibility layer in the V4L2 videodev module +can translate V4L ioctl requests to their V4L2 counterpart, however a +V4L2 driver usually needs more preparation to become fully V4L +compatible. This is covered in more detail in . +
+ +
+ Querying Capabilities + + The V4L VIDIOCGCAP ioctl is +equivalent to V4L2's &VIDIOC-QUERYCAP;. + + The name field in struct +video_capability became +card in &v4l2-capability;, +type was replaced by +capabilities. Note V4L2 does not +distinguish between device types like this, better think of basic +video input, video output and radio devices supporting a set of +related functions like video capturing, video overlay and VBI +capturing. See for an +introduction. + + + + struct +video_capability +type + &v4l2-capability; +capabilities flags + Purpose + + + + + VID_TYPE_CAPTURE + V4L2_CAP_VIDEO_CAPTURE + The video +capture interface is supported. + + + VID_TYPE_TUNER + V4L2_CAP_TUNER + The device has a tuner or +modulator. + + + VID_TYPE_TELETEXT + V4L2_CAP_VBI_CAPTURE + The raw VBI +capture interface is supported. + + + VID_TYPE_OVERLAY + V4L2_CAP_VIDEO_OVERLAY + The video +overlay interface is supported. + + + VID_TYPE_CHROMAKEY + V4L2_FBUF_CAP_CHROMAKEY in +field capability of +&v4l2-framebuffer; + Whether chromakey overlay is supported. For +more information on overlay see +. + + + VID_TYPE_CLIPPING + V4L2_FBUF_CAP_LIST_CLIPPING +and V4L2_FBUF_CAP_BITMAP_CLIPPING in field +capability of &v4l2-framebuffer; + Whether clipping the overlaid image is +supported, see . + + + VID_TYPE_FRAMERAM + V4L2_FBUF_CAP_EXTERNOVERLAY +not set in field +capability of &v4l2-framebuffer; + Whether overlay overwrites frame buffer memory, +see . + + + VID_TYPE_SCALES + - + This flag indicates if the hardware can scale +images. The V4L2 API implies the scale factor by setting the cropping +dimensions and image size with the &VIDIOC-S-CROP; and &VIDIOC-S-FMT; +ioctl, respectively. The driver returns the closest sizes possible. +For more information on cropping and scaling see . + + + VID_TYPE_MONOCHROME + - + Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports grey scale capturing only. For more information on image +formats see . + + + VID_TYPE_SUBCAPTURE + - + Applications can call the &VIDIOC-G-CROP; ioctl +to determine if the device supports capturing a subsection of the full +picture ("cropping" in V4L2). If not, the ioctl returns the &EINVAL;. +For more information on cropping and scaling see . + + + VID_TYPE_MPEG_DECODER + - + Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports MPEG streams. + + + VID_TYPE_MPEG_ENCODER + - + See above. + + + VID_TYPE_MJPEG_DECODER + - + See above. + + + VID_TYPE_MJPEG_ENCODER + - + See above. + + + + + + The audios field was replaced +by capabilities flag +V4L2_CAP_AUDIO, indicating +if the device has any audio inputs or outputs. To +determine their number applications can enumerate audio inputs with +the &VIDIOC-G-AUDIO; ioctl. The audio ioctls are described in . + + The maxwidth, +maxheight, +minwidth and +minheight fields were removed. Calling the +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; ioctl with the desired dimensions +returns the closest size possible, taking into account the current +video standard, cropping and scaling limitations. +
+ +
+ Video Sources + + V4L provides the VIDIOCGCHAN and +VIDIOCSCHAN ioctl using struct +video_channel to enumerate +the video inputs of a V4L device. The equivalent V4L2 ioctls +are &VIDIOC-ENUMINPUT;, &VIDIOC-G-INPUT; and &VIDIOC-S-INPUT; +using &v4l2-input; as discussed in . + + The channel field counting +inputs was renamed to index, the video +input types were renamed as follows: + + + + struct video_channel +type + &v4l2-input; +type + + + + + VIDEO_TYPE_TV + V4L2_INPUT_TYPE_TUNER + + + VIDEO_TYPE_CAMERA + V4L2_INPUT_TYPE_CAMERA + + + + + + Unlike the tuners field +expressing the number of tuners of this input, V4L2 assumes each video +input is connected to at most one tuner. However a tuner can have more +than one input, &ie; RF connectors, and a device can have multiple +tuners. The index number of the tuner associated with the input, if +any, is stored in field tuner of +&v4l2-input;. Enumeration of tuners is discussed in . + + The redundant VIDEO_VC_TUNER flag was +dropped. Video inputs associated with a tuner are of type +V4L2_INPUT_TYPE_TUNER. The +VIDEO_VC_AUDIO flag was replaced by the +audioset field. V4L2 considers devices with +up to 32 audio inputs. Each set bit in the +audioset field represents one audio input +this video input combines with. For information about audio inputs and +how to switch between them see . + + The norm field describing the +supported video standards was replaced by +std. The V4L specification mentions a flag +VIDEO_VC_NORM indicating whether the standard can +be changed. This flag was a later addition together with the +norm field and has been removed in the +meantime. V4L2 has a similar, albeit more comprehensive approach +to video standards, see for more +information. +
+ +
+ Tuning + + The V4L VIDIOCGTUNER and +VIDIOCSTUNER ioctl and struct +video_tuner can be used to enumerate the +tuners of a V4L TV or radio device. The equivalent V4L2 ioctls are +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; using &v4l2-tuner;. Tuners are +covered in . + + The tuner field counting tuners +was renamed to index. The fields +name, rangelow +and rangehigh remained unchanged. + + The VIDEO_TUNER_PAL, +VIDEO_TUNER_NTSC and +VIDEO_TUNER_SECAM flags indicating the supported +video standards were dropped. This information is now contained in the +associated &v4l2-input;. No replacement exists for the +VIDEO_TUNER_NORM flag indicating whether the +video standard can be switched. The mode +field to select a different video standard was replaced by a whole new +set of ioctls and structures described in . +Due to its ubiquity it should be mentioned the BTTV driver supports +several standards in addition to the regular +VIDEO_MODE_PAL (0), +VIDEO_MODE_NTSC, +VIDEO_MODE_SECAM and +VIDEO_MODE_AUTO (3). Namely N/PAL Argentina, +M/PAL, N/PAL, and NTSC Japan with numbers 3-6 (sic). + + The VIDEO_TUNER_STEREO_ON flag +indicating stereo reception became +V4L2_TUNER_SUB_STEREO in field +rxsubchans. This field also permits the +detection of monaural and bilingual audio, see the definition of +&v4l2-tuner; for details. Presently no replacement exists for the +VIDEO_TUNER_RDS_ON and +VIDEO_TUNER_MBS_ON flags. + + The VIDEO_TUNER_LOW flag was renamed +to V4L2_TUNER_CAP_LOW in the &v4l2-tuner; +capability field. + + The VIDIOCGFREQ and +VIDIOCSFREQ ioctl to change the tuner frequency +where renamed to &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY;. They +take a pointer to a &v4l2-frequency; instead of an unsigned long +integer. +
+ +
+ Image Properties + + V4L2 has no equivalent of the +VIDIOCGPICT and VIDIOCSPICT +ioctl and struct video_picture. The following +fields where replaced by V4L2 controls accessible with the +&VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls: + + + + struct video_picture + V4L2 Control ID + + + + + brightness + V4L2_CID_BRIGHTNESS + + + hue + V4L2_CID_HUE + + + colour + V4L2_CID_SATURATION + + + contrast + V4L2_CID_CONTRAST + + + whiteness + V4L2_CID_WHITENESS + + + + + + The V4L picture controls are assumed to range from 0 to +65535 with no particular reset value. The V4L2 API permits arbitrary +limits and defaults which can be queried with the &VIDIOC-QUERYCTRL; +ioctl. For general information about controls see . + + The depth (average number of +bits per pixel) of a video image is implied by the selected image +format. V4L2 does not explicitely provide such information assuming +applications recognizing the format are aware of the image depth and +others need not know. The palette field +moved into the &v4l2-pix-format;: + + + + struct video_picture +palette + &v4l2-pix-format; +pixfmt + + + + + VIDEO_PALETTE_GREY + V4L2_PIX_FMT_GREY + + + VIDEO_PALETTE_HI240 + V4L2_PIX_FMT_HI240 + This is a custom format used by the BTTV +driver, not one of the V4L2 standard formats. + + + + VIDEO_PALETTE_RGB565 + V4L2_PIX_FMT_RGB565 + + + VIDEO_PALETTE_RGB555 + V4L2_PIX_FMT_RGB555 + + + VIDEO_PALETTE_RGB24 + V4L2_PIX_FMT_BGR24 + + + VIDEO_PALETTE_RGB32 + V4L2_PIX_FMT_BGR32 + Presumably all V4L RGB formats are +little-endian, although some drivers might interpret them according to machine endianess. V4L2 defines little-endian, big-endian and red/blue +swapped variants. For details see . + + + + VIDEO_PALETTE_YUV422 + V4L2_PIX_FMT_YUYV + + + VIDEO_PALETTE_YUYV + VIDEO_PALETTE_YUV422 +and VIDEO_PALETTE_YUYV are the same formats. Some +V4L drivers respond to one, some to the other. + + V4L2_PIX_FMT_YUYV + + + VIDEO_PALETTE_UYVY + V4L2_PIX_FMT_UYVY + + + VIDEO_PALETTE_YUV420 + None + + + VIDEO_PALETTE_YUV411 + V4L2_PIX_FMT_Y41P + Not to be confused with +V4L2_PIX_FMT_YUV411P, which is a planar +format. + + + VIDEO_PALETTE_RAW + None V4L explains this +as: "RAW capture (BT848)" + + + VIDEO_PALETTE_YUV422P + V4L2_PIX_FMT_YUV422P + + + VIDEO_PALETTE_YUV411P + V4L2_PIX_FMT_YUV411P + Not to be confused with +V4L2_PIX_FMT_Y41P, which is a packed +format. + + + VIDEO_PALETTE_YUV420P + V4L2_PIX_FMT_YVU420 + + + VIDEO_PALETTE_YUV410P + V4L2_PIX_FMT_YVU410 + + + + + + V4L2 image formats are defined in . The image format can be selected with the +&VIDIOC-S-FMT; ioctl. +
+ +
+ Audio + + The VIDIOCGAUDIO and +VIDIOCSAUDIO ioctl and struct +video_audio are used to enumerate the +audio inputs of a V4L device. The equivalent V4L2 ioctls are +&VIDIOC-G-AUDIO; and &VIDIOC-S-AUDIO; using &v4l2-audio; as +discussed in . + + The audio "channel number" +field counting audio inputs was renamed to +index. + + On VIDIOCSAUDIO the +mode field selects one +of the VIDEO_SOUND_MONO, +VIDEO_SOUND_STEREO, +VIDEO_SOUND_LANG1 or +VIDEO_SOUND_LANG2 audio demodulation modes. When +the current audio standard is BTSC +VIDEO_SOUND_LANG2 refers to SAP and +VIDEO_SOUND_LANG1 is meaningless. Also +undocumented in the V4L specification, there is no way to query the +selected mode. On VIDIOCGAUDIO the driver returns +the actually received audio programmes in this +field. In the V4L2 API this information is stored in the &v4l2-tuner; +rxsubchans and +audmode fields, respectively. See for more information on tuners. Related to audio +modes &v4l2-audio; also reports if this is a mono or stereo +input, regardless if the source is a tuner. + + The following fields where replaced by V4L2 controls +accessible with the &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls: + + + + struct +video_audio + V4L2 Control ID + + + + + volume + V4L2_CID_AUDIO_VOLUME + + + bass + V4L2_CID_AUDIO_BASS + + + treble + V4L2_CID_AUDIO_TREBLE + + + balance + V4L2_CID_AUDIO_BALANCE + + + + + + To determine which of these controls are supported by a +driver V4L provides the flags +VIDEO_AUDIO_VOLUME, +VIDEO_AUDIO_BASS, +VIDEO_AUDIO_TREBLE and +VIDEO_AUDIO_BALANCE. In the V4L2 API the +&VIDIOC-QUERYCTRL; ioctl reports if the respective control is +supported. Accordingly the VIDEO_AUDIO_MUTABLE +and VIDEO_AUDIO_MUTE flags where replaced by the +boolean V4L2_CID_AUDIO_MUTE control. + + All V4L2 controls have a step +attribute replacing the struct video_audio +step field. The V4L audio controls are +assumed to range from 0 to 65535 with no particular reset value. The +V4L2 API permits arbitrary limits and defaults which can be queried +with the &VIDIOC-QUERYCTRL; ioctl. For general information about +controls see . +
+ +
+ Frame Buffer Overlay + + The V4L2 ioctls equivalent to +VIDIOCGFBUF and VIDIOCSFBUF +are &VIDIOC-G-FBUF; and &VIDIOC-S-FBUF;. The +base field of struct +video_buffer remained unchanged, except V4L2 +defines a flag to indicate non-destructive overlays instead of a +NULL pointer. All other fields moved into the +&v4l2-pix-format; fmt substructure of +&v4l2-framebuffer;. The depth field was +replaced by pixelformat. See for a list of RGB formats and their +respective color depths. + + Instead of the special ioctls +VIDIOCGWIN and VIDIOCSWIN +V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument. Here the win +member of the fmt union is used, a +&v4l2-window;. + + The x, +y, width and +height fields of struct +video_window moved into &v4l2-rect; +substructure w of struct +v4l2_window. The +chromakey, +clips, and +clipcount fields remained unchanged. Struct +video_clip was renamed to &v4l2-clip;, also +containing a struct v4l2_rect, but the +semantics are still the same. + + The VIDEO_WINDOW_INTERLACE flag was +dropped. Instead applications must set the +field field to +V4L2_FIELD_ANY or +V4L2_FIELD_INTERLACED. The +VIDEO_WINDOW_CHROMAKEY flag moved into +&v4l2-framebuffer;, under the new name +V4L2_FBUF_FLAG_CHROMAKEY. + + In V4L, storing a bitmap pointer in +clips and setting +clipcount to +VIDEO_CLIP_BITMAP (-1) requests bitmap +clipping, using a fixed size bitmap of 1024 × 625 bits. Struct +v4l2_window has a separate +bitmap pointer field for this purpose and +the bitmap size is determined by w.width and +w.height. + + The VIDIOCCAPTURE ioctl to enable or +disable overlay was renamed to &VIDIOC-OVERLAY;. +
+ +
+ Cropping + + To capture only a subsection of the full picture V4L +defines the VIDIOCGCAPTURE and +VIDIOCSCAPTURE ioctls using struct +video_capture. The equivalent V4L2 ioctls are +&VIDIOC-G-CROP; and &VIDIOC-S-CROP; using &v4l2-crop;, and the related +&VIDIOC-CROPCAP; ioctl. This is a rather complex matter, see + for details. + + The x, +y, width and +height fields moved into &v4l2-rect; +substructure c of struct +v4l2_crop. The +decimation field was dropped. In the V4L2 +API the scaling factor is implied by the size of the cropping +rectangle and the size of the captured or overlaid image. + + The VIDEO_CAPTURE_ODD +and VIDEO_CAPTURE_EVEN flags to capture only the +odd or even field, respectively, were replaced by +V4L2_FIELD_TOP and +V4L2_FIELD_BOTTOM in the field named +field of &v4l2-pix-format; and +&v4l2-window;. These structures are used to select a capture or +overlay format with the &VIDIOC-S-FMT; ioctl. +
+ +
+ Reading Images, Memory Mapping + +
+ Capturing using the read method + + There is no essential difference between reading images +from a V4L or V4L2 device using the &func-read; function, however V4L2 +drivers are not required to support this I/O method. Applications can +determine if the function is available with the &VIDIOC-QUERYCAP; +ioctl. All V4L2 devices exchanging data with applications must support +the &func-select; and &func-poll; functions. + + To select an image format and size, V4L provides the +VIDIOCSPICT and VIDIOCSWIN +ioctls. V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument, here the &v4l2-pix-format; named +pix of its fmt +union is used. + + For more information about the V4L2 read interface see +. +
+
+ Capturing using memory mapping + + Applications can read from V4L devices by mapping +buffers in device memory, or more often just buffers allocated in +DMA-able system memory, into their address space. This avoids the data +copying overhead of the read method. V4L2 supports memory mapping as +well, with a few differences. + + + + + + V4L + V4L2 + + + + + + The image format must be selected before +buffers are allocated, with the &VIDIOC-S-FMT; ioctl. When no format +is selected the driver may use the last, possibly by another +application requested format. + + + Applications cannot change the number of +buffers. The it is built into the driver, unless it has a module +option to change the number when the driver module is +loaded. + The &VIDIOC-REQBUFS; ioctl allocates the +desired number of buffers, this is a required step in the initialization +sequence. + + + Drivers map all buffers as one contiguous +range of memory. The VIDIOCGMBUF ioctl is +available to query the number of buffers, the offset of each buffer +from the start of the virtual file, and the overall amount of memory +used, which can be used as arguments for the &func-mmap; +function. + Buffers are individually mapped. The +offset and size of each buffer can be determined with the +&VIDIOC-QUERYBUF; ioctl. + + + The VIDIOCMCAPTURE +ioctl prepares a buffer for capturing. It also determines the image +format for this buffer. The ioctl returns immediately, eventually with +an &EAGAIN; if no video signal had been detected. When the driver +supports more than one buffer applications can call the ioctl multiple +times and thus have multiple outstanding capture +requests.The VIDIOCSYNC ioctl +suspends execution until a particular buffer has been +filled. + Drivers maintain an incoming and outgoing +queue. &VIDIOC-QBUF; enqueues any empty buffer into the incoming +queue. Filled buffers are dequeued from the outgoing queue with the +&VIDIOC-DQBUF; ioctl. To wait until filled buffers become available this +function, &func-select; or &func-poll; can be used. The +&VIDIOC-STREAMON; ioctl must be called once after enqueuing one or +more buffers to start capturing. Its counterpart +&VIDIOC-STREAMOFF; stops capturing and dequeues all buffers from both +queues. Applications can query the signal status, if known, with the +&VIDIOC-ENUMINPUT; ioctl. + + + + + + For a more in-depth discussion of memory mapping and +examples, see . +
+
+ +
+ Reading Raw VBI Data + + Originally the V4L API did not specify a raw VBI capture +interface, only the device file /dev/vbi was +reserved for this purpose. The only driver supporting this interface +was the BTTV driver, de-facto defining the V4L VBI interface. Reading +from the device yields a raw VBI image with the following +parameters: + + + + &v4l2-vbi-format; + V4L, BTTV driver + + + + + sampling_rate + 28636363 Hz NTSC (or any other 525-line +standard); 35468950 Hz PAL and SECAM (625-line standards) + + + offset + ? + + + samples_per_line + 2048 + + + sample_format + V4L2_PIX_FMT_GREY. The last four bytes (a +machine endianess integer) contain a frame counter. + + + start[] + 10, 273 NTSC; 22, 335 PAL and SECAM + + + count[] + 16, 16Old driver +versions used different values, eventually the custom +BTTV_VBISIZE ioctl was added to query the +correct values. + + + flags + 0 + + + + + + Undocumented in the V4L specification, in Linux 2.3 the +VIDIOCGVBIFMT and +VIDIOCSVBIFMT ioctls using struct +vbi_format were added to determine the VBI +image parameters. These ioctls are only partially compatible with the +V4L2 VBI interface specified in . + + An offset field does not +exist, sample_format is supposed to be +VIDEO_PALETTE_RAW, equivalent to +V4L2_PIX_FMT_GREY. The remaining fields are +probably equivalent to &v4l2-vbi-format;. + + Apparently only the Zoran (ZR 36120) driver implements +these ioctls. The semantics differ from those specified for V4L2 in two +ways. The parameters are reset on &func-open; and +VIDIOCSVBIFMT always returns an &EINVAL; if the +parameters are invalid. +
+ +
+ Miscellaneous + + V4L2 has no equivalent of the +VIDIOCGUNIT ioctl. Applications can find the VBI +device associated with a video capture device (or vice versa) by +reopening the device and requesting VBI data. For details see +. + + No replacement exists for VIDIOCKEY, +and the V4L functions for microcode programming. A new interface for +MPEG compression and playback devices is documented in . +
+ +
+ +
+ Changes of the V4L2 API + + Soon after the V4L API was added to the kernel it was +criticised as too inflexible. In August 1998 Bill Dirks proposed a +number of improvements and began to work on documentation, example +drivers and applications. With the help of other volunteers this +eventually became the V4L2 API, not just an extension but a +replacement for the V4L API. However it took another four years and +two stable kernel releases until the new API was finally accepted for +inclusion into the kernel in its present form. + +
+ Early Versions + 1998-08-20: First version. + + 1998-08-27: The &func-select; function was introduced. + + 1998-09-10: New video standard interface. + + 1998-09-18: The VIDIOC_NONCAP ioctl +was replaced by the otherwise meaningless O_TRUNC +&func-open; flag, and the aliases O_NONCAP and +O_NOIO were defined. Applications can set this +flag if they intend to access controls only, as opposed to capture +applications which need exclusive access. The +VIDEO_STD_XXX identifiers are now ordinals +instead of flags, and the video_std_construct() +helper function takes id and transmission arguments. + + 1998-09-28: Revamped video standard. Made video controls +individually enumerable. + + 1998-10-02: The id field was +removed from struct video_standard and the +color subcarrier fields were renamed. The &VIDIOC-QUERYSTD; ioctl was +renamed to &VIDIOC-ENUMSTD;, &VIDIOC-G-INPUT; to &VIDIOC-ENUMINPUT;. A +first draft of the Codec API was released. + + 1998-11-08: Many minor changes. Most symbols have been +renamed. Some material changes to &v4l2-capability;. + + 1998-11-12: The read/write directon of some ioctls was misdefined. + + 1998-11-14: V4L2_PIX_FMT_RGB24 +changed to V4L2_PIX_FMT_BGR24, and +V4L2_PIX_FMT_RGB32 changed to +V4L2_PIX_FMT_BGR32. Audio controls are now +accessible with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls under +names starting with V4L2_CID_AUDIO. The +V4L2_MAJOR define was removed from +videodev.h since it was only used once in the +videodev kernel module. The +YUV422 and YUV411 planar +image formats were added. + + 1998-11-28: A few ioctl symbols changed. Interfaces for codecs and +video output devices were added. + + 1999-01-14: A raw VBI capture interface was added. + + 1999-01-19: The VIDIOC_NEXTBUF ioctl + was removed. +
+ +
+ V4L2 Version 0.16 1999-01-31 + 1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF +are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added +digital zoom (cropping) controls. +
+ + + +
+ V4L2 Version 0.18 1999-03-16 + Added a v4l to V4L2 ioctl compatibility layer to +videodev.c. Driver writers, this changes how you implement your ioctl +handler. See the Driver Writer's Guide. Added some more control id +codes. +
+ +
+ V4L2 Version 0.19 1999-06-05 + 1999-03-18: Fill in the category and catname fields of +v4l2_queryctrl objects before passing them to the driver. Required a +minor change to the VIDIOC_QUERYCTRL handlers in the sample +drivers. + 1999-03-31: Better compatibility for v4l memory capture +ioctls. Requires changes to drivers to fully support new compatibility +features, see Driver Writer's Guide and v4l2cap.c. Added new control +IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P, +and _YUV411P to _YUV411P. + 1999-04-04: Added a few more control IDs. + 1999-04-07: Added the button control type. + 1999-05-02: Fixed a typo in videodev.h, and added the +V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag. + 1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing +a malfunction of this ioctl. + 1999-06-05: Changed the value of +V4L2_CID_WHITENESS. +
+ +
+ V4L2 Version 0.20 (1999-09-10) + + Version 0.20 introduced a number of changes which were +not backward compatible with 0.19 and earlier +versions. Purpose of these changes was to simplify the API, while +making it more extensible and following common Linux driver API +conventions. + + + + Some typos in V4L2_FMT_FLAG +symbols were fixed. &v4l2-clip; was changed for compatibility with +v4l. (1999-08-30) + + + + V4L2_TUNER_SUB_LANG1 was added. +(1999-09-05) + + + + All ioctl() commands that used an integer argument now +take a pointer to an integer. Where it makes sense, ioctls will return +the actual new value in the integer pointed to by the argument, a +common convention in the V4L2 API. The affected ioctls are: +VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ, +VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example + +err = ioctl (fd, VIDIOC_XXX, V4L2_XXX); + becomes +int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &a); + + + + + + All the different get- and set-format commands were +swept into one &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctl taking a union +and a type field selecting the union member as parameter. Purpose is to +simplify the API by eliminating several ioctls and to allow new and +driver private data streams without adding new ioctls. + + This change obsoletes the following ioctls: +VIDIOC_S_INFMT, +VIDIOC_G_INFMT, +VIDIOC_S_OUTFMT, +VIDIOC_G_OUTFMT, +VIDIOC_S_VBIFMT and +VIDIOC_G_VBIFMT. The image format structure +v4l2_format was renamed to &v4l2-pix-format;, +while &v4l2-format; is now the envelopping structure for all format +negotiations. + + + + Similar to the changes above, the +VIDIOC_G_PARM and +VIDIOC_S_PARM ioctls were merged with +VIDIOC_G_OUTPARM and +VIDIOC_S_OUTPARM. A +type field in the new &v4l2-streamparm; +selects the respective union member. + + This change obsoletes the +VIDIOC_G_OUTPARM and +VIDIOC_S_OUTPARM ioctls. + + + + Control enumeration was simplified, and two new +control flags were introduced and one dropped. The +catname field was replaced by a +group field. + + Drivers can now flag unsupported and temporarily +unavailable controls with V4L2_CTRL_FLAG_DISABLED +and V4L2_CTRL_FLAG_GRABBED respectively. The +group name indicates a possibly narrower +classification than the category. In other +words, there may be multiple groups within a category. Controls within +a group would typically be drawn within a group box. Controls in +different categories might have a greater separation, or may even +appear in separate windows. + + + + The &v4l2-buffer; timestamp +was changed to a 64 bit integer, containing the sampling or output +time of the frame in nanoseconds. Additionally timestamps will be in +absolute system time, not starting from zero at the beginning of a +stream. The data type name for timestamps is stamp_t, defined as a +signed 64-bit integer. Output devices should not send a buffer out +until the time in the timestamp field has arrived. I would like to +follow SGI's lead, and adopt a multimedia timestamping system like +their UST (Unadjusted System Time). See +http://web.archive.org/web/*/http://reality.sgi.com +/cpirazzi_engr/lg/time/intro.html. +UST uses timestamps that are 64-bit signed integers +(not struct timeval's) and given in nanosecond units. The UST clock +starts at zero when the system is booted and runs continuously and +uniformly. It takes a little over 292 years for UST to overflow. There +is no way to set the UST clock. The regular Linux time-of-day clock +can be changed periodically, which would cause errors if it were being +used for timestamping a multimedia stream. A real UST style clock will +require some support in the kernel that is not there yet. But in +anticipation, I will change the timestamp field to a 64-bit integer, +and I will change the v4l2_masterclock_gettime() function (used only +by drivers) to return a 64-bit integer. + + + + A sequence field was added +to &v4l2-buffer;. The sequence field counts +captured frames, it is ignored by output devices. When a capture +driver drops a frame, the sequence number of that frame is +skipped. + + +
+ +
+ V4L2 Version 0.20 incremental changes + + + 1999-12-23: In &v4l2-vbi-format; the +reserved1 field became +offset. Previously drivers were required to +clear the reserved1 field. + + 2000-01-13: The + V4L2_FMT_FLAG_NOT_INTERLACED flag was added. + + 2000-07-31: The linux/poll.h header +is now included by videodev.h for compatibility +with the original videodev.h file. + + 2000-11-20: V4L2_TYPE_VBI_OUTPUT and +V4L2_PIX_FMT_Y41P were added. + + 2000-11-25: V4L2_TYPE_VBI_INPUT was +added. + + 2000-12-04: A couple typos in symbol names were fixed. + + 2001-01-18: To avoid namespace conflicts the +fourcc macro defined in the +videodev.h header file was renamed to +v4l2_fourcc. + + 2001-01-25: A possible driver-level compatibility problem +between the videodev.h file in Linux 2.4.0 and +the videodev.h file included in the +videodevX patch was fixed. Users of an earlier +version of videodevX on Linux 2.4.0 should +recompile their V4L and V4L2 drivers. + + 2001-01-26: A possible kernel-level incompatibility +between the videodev.h file in the +videodevX patch and the +videodev.h file in Linux 2.2.x with devfs patches +applied was fixed. + + 2001-03-02: Certain V4L ioctls which pass data in both +direction although they are defined with read-only parameter, did not +work correctly through the backward compatibility layer. +[Solution?] + + 2001-04-13: Big endian 16-bit RGB formats were added. + + 2001-09-17: New YUV formats and the &VIDIOC-G-FREQUENCY; and +&VIDIOC-S-FREQUENCY; ioctls were added. (The old +VIDIOC_G_FREQ and +VIDIOC_S_FREQ ioctls did not take multiple tuners +into account.) + + 2000-09-18: V4L2_BUF_TYPE_VBI was +added. This may break compatibility as the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls may fail now if the struct +v4l2_fmt type +field does not contain V4L2_BUF_TYPE_VBI. In the +documentation of the &v4l2-vbi-format; +offset field the ambiguous phrase "rising +edge" was changed to "leading edge". +
+ +
+ V4L2 Version 0.20 2000-11-23 + + A number of changes were made to the raw VBI +interface. + + + + Figures clarifying the line numbering scheme were +added to the V4L2 API specification. The +start[0] and +start[1] fields no longer count line +numbers beginning at zero. Rationale: a) The previous definition was +unclear. b) The start[] values are ordinal +numbers. c) There is no point in inventing a new line numbering +scheme. We now use line number as defined by ITU-R, period. +Compatibility: Add one to the start values. Applications depending on +the previous semantics may not function correctly. + + + + The restriction "count[0] > 0 and count[1] > 0" +has been relaxed to "(count[0] + count[1]) > 0". Rationale: +Drivers may allocate resources at scan line granularity and some data +services are transmitted only on the first field. The comment that +both count values will usually be equal is +misleading and pointless and has been removed. This change +breaks compatibility with earlier versions: +Drivers may return EINVAL, applications may not function +correctly. + + + + Drivers are again permitted to return negative +(unknown) start values as proposed earlier. Why this feature was +dropped is unclear. This change may break +compatibility with applications depending on the start +values being positive. The use of EBUSY and +EINVAL error codes with the &VIDIOC-S-FMT; ioctl +was clarified. The &EBUSY; was finally documented, and the +reserved2 field which was previously +mentioned only in the videodev.h header +file. + + + + New buffer types +V4L2_TYPE_VBI_INPUT and +V4L2_TYPE_VBI_OUTPUT were added. The former is an +alias for the old V4L2_TYPE_VBI, the latter was +missing in the videodev.h file. + + +
+ +
+ V4L2 Version 0.20 2002-07-25 + Added sliced VBI interface proposal. +
+ +
+ V4L2 in Linux 2.5.46, 2002-10 + + Around October-November 2002, prior to an announced +feature freeze of Linux 2.5, the API was revised, drawing from +experience with V4L2 0.20. This unnamed version was finally merged +into Linux 2.5.46. + + + + As specified in , drivers +must make related device functions available under all minor device +numbers. + + + + The &func-open; function requires access mode +O_RDWR regardless of the device type. All V4L2 +drivers exchanging data with applications must support the +O_NONBLOCK flag. The O_NOIO +flag, a V4L2 symbol which aliased the meaningless +O_TRUNC to indicate accesses without data +exchange (panel applications) was dropped. Drivers must stay in "panel +mode" until the application attempts to initiate a data exchange, see +. + + + + The &v4l2-capability; changed dramatically. Note that +also the size of the structure changed, which is encoded in the ioctl +request code, thus older V4L2 devices will respond with an &EINVAL; to +the new &VIDIOC-QUERYCAP; ioctl. + + There are new fields to identify the driver, a new RDS +device function V4L2_CAP_RDS_CAPTURE, the +V4L2_CAP_AUDIO flag indicates if the device has +any audio connectors, another I/O capability +V4L2_CAP_ASYNCIO can be flagged. In response to +these changes the type field became a bit +set and was merged into the flags field. +V4L2_FLAG_TUNER was renamed to +V4L2_CAP_TUNER, +V4L2_CAP_VIDEO_OVERLAY replaced +V4L2_FLAG_PREVIEW and +V4L2_CAP_VBI_CAPTURE and +V4L2_CAP_VBI_OUTPUT replaced +V4L2_FLAG_DATA_SERVICE. +V4L2_FLAG_READ and +V4L2_FLAG_WRITE were merged into +V4L2_CAP_READWRITE. + + The redundant fields +inputs, outputs +and audios were removed. These properties +can be determined as described in and . + + The somewhat volatile and therefore barely useful +fields maxwidth, +maxheight, +minwidth, +minheight, +maxframerate were removed. This information +is available as described in and +. + + V4L2_FLAG_SELECT was removed. We +believe the select() function is important enough to require support +of it in all V4L2 drivers exchanging data with applications. The +redundant V4L2_FLAG_MONOCHROME flag was removed, +this information is available as described in . + + + + In &v4l2-input; the +assoc_audio field and the +capability field and its only flag +V4L2_INPUT_CAP_AUDIO was replaced by the new +audioset field. Instead of linking one +video input to one audio input this field reports all audio inputs +this video input combines with. + + New fields are tuner +(reversing the former link from tuners to video inputs), +std and +status. + + Accordingly &v4l2-output; lost its +capability and +assoc_audio fields. +audioset, +modulator and +std where added instead. + + + + The &v4l2-audio; field +audio was renamed to +index, for consistency with other +structures. A new capability flag +V4L2_AUDCAP_STEREO was added to indicated if the +audio input in question supports stereo sound. +V4L2_AUDCAP_EFFECTS and the corresponding +V4L2_AUDMODE flags where removed. This can be +easily implemented using controls. (However the same applies to AVL +which is still there.) + + Again for consistency the &v4l2-audioout; field +audio was renamed to +index. + + + + The &v4l2-tuner; +input field was replaced by an +index field, permitting devices with +multiple tuners. The link between video inputs and tuners is now +reversed, inputs point to their tuner. The +std substructure became a +simple set (more about this below) and moved into &v4l2-input;. A +type field was added. + + Accordingly in &v4l2-modulator; the +output was replaced by an +index field. + + In &v4l2-frequency; the +port field was replaced by a +tuner field containing the respective tuner +or modulator index number. A tuner type +field was added and the reserved field +became larger for future extensions (satellite tuners in +particular). + + + + The idea of completely transparent video standards was +dropped. Experience showed that applications must be able to work with +video standards beyond presenting the user a menu. Instead of +enumerating supported standards with an ioctl applications can now +refer to standards by &v4l2-std-id; and symbols defined in the +videodev2.h header file. For details see . The &VIDIOC-G-STD; and +&VIDIOC-S-STD; now take a pointer to this type as argument. +&VIDIOC-QUERYSTD; was added to autodetect the received standard, if +the hardware has this capability. In &v4l2-standard; an +index field was added for &VIDIOC-ENUMSTD;. +A &v4l2-std-id; field named id was added as +machine readable identifier, also replacing the +transmission field. The misleading +framerate field was renamed +to frameperiod. The now obsolete +colorstandard information, originally +needed to distguish between variations of standards, were +removed. + + Struct v4l2_enumstd ceased to +be. &VIDIOC-ENUMSTD; now takes a pointer to a &v4l2-standard; +directly. The information which standards are supported by a +particular video input or output moved into &v4l2-input; and +&v4l2-output; fields named std, +respectively. + + + + The &v4l2-queryctrl; fields +category and +group did not catch on and/or were not +implemented as expected and therefore removed. + + + + The &VIDIOC-TRY-FMT; ioctl was added to negotiate data +formats as with &VIDIOC-S-FMT;, but without the overhead of +programming the hardware and regardless of I/O in progress. + + In &v4l2-format; the fmt +union was extended to contain &v4l2-window;. All image format +negotiations are now possible with VIDIOC_G_FMT, +VIDIOC_S_FMT and +VIDIOC_TRY_FMT; ioctl. The +VIDIOC_G_WIN and +VIDIOC_S_WIN ioctls to prepare for a video +overlay were removed. The type field +changed to type &v4l2-buf-type; and the buffer type names changed as +follows. + + + + Old defines + &v4l2-buf-type; + + + + + V4L2_BUF_TYPE_CAPTURE + V4L2_BUF_TYPE_VIDEO_CAPTURE + + + V4L2_BUF_TYPE_CODECIN + Omitted for now + + + V4L2_BUF_TYPE_CODECOUT + Omitted for now + + + V4L2_BUF_TYPE_EFFECTSIN + Omitted for now + + + V4L2_BUF_TYPE_EFFECTSIN2 + Omitted for now + + + V4L2_BUF_TYPE_EFFECTSOUT + Omitted for now + + + V4L2_BUF_TYPE_VIDEOOUT + V4L2_BUF_TYPE_VIDEO_OUTPUT + + + - + V4L2_BUF_TYPE_VIDEO_OVERLAY + + + - + V4L2_BUF_TYPE_VBI_CAPTURE + + + - + V4L2_BUF_TYPE_VBI_OUTPUT + + + - + V4L2_BUF_TYPE_SLICED_VBI_CAPTURE + + + - + V4L2_BUF_TYPE_SLICED_VBI_OUTPUT + + + V4L2_BUF_TYPE_PRIVATE_BASE + V4L2_BUF_TYPE_PRIVATE + + + + + + + + In &v4l2-fmtdesc; a &v4l2-buf-type; field named +type was added as in &v4l2-format;. The +VIDIOC_ENUM_FBUFFMT ioctl is no longer needed and +was removed. These calls can be replaced by &VIDIOC-ENUM-FMT; with +type V4L2_BUF_TYPE_VIDEO_OVERLAY. + + + + In &v4l2-pix-format; the +depth field was removed, assuming +applications which recognize the format by its four-character-code +already know the color depth, and others do not care about it. The +same rationale lead to the removal of the +V4L2_FMT_FLAG_COMPRESSED flag. The +V4L2_FMT_FLAG_SWCONVECOMPRESSED flag was removed +because drivers are not supposed to convert images in kernel space. A +user library of conversion functions should be provided instead. The +V4L2_FMT_FLAG_BYTESPERLINE flag was redundant. +Applications can set the bytesperline field +to zero to get a reasonable default. Since the remaining flags were +replaced as well, the flags field itself +was removed. + The interlace flags were replaced by a &v4l2-field; +value in a newly added field +field. + + + + Old flag + &v4l2-field; + + + + + V4L2_FMT_FLAG_NOT_INTERLACED + ? + + + V4L2_FMT_FLAG_INTERLACED += V4L2_FMT_FLAG_COMBINED + V4L2_FIELD_INTERLACED + + + V4L2_FMT_FLAG_TOPFIELD += V4L2_FMT_FLAG_ODDFIELD + V4L2_FIELD_TOP + + + V4L2_FMT_FLAG_BOTFIELD += V4L2_FMT_FLAG_EVENFIELD + V4L2_FIELD_BOTTOM + + + - + V4L2_FIELD_SEQ_TB + + + - + V4L2_FIELD_SEQ_BT + + + - + V4L2_FIELD_ALTERNATE + + + + + + The color space flags were replaced by a +&v4l2-colorspace; value in a newly added +colorspace field, where one of +V4L2_COLORSPACE_SMPTE170M, +V4L2_COLORSPACE_BT878, +V4L2_COLORSPACE_470_SYSTEM_M or +V4L2_COLORSPACE_470_SYSTEM_BG replaces +V4L2_FMT_CS_601YUV. + + + + In &v4l2-requestbuffers; the +type field was properly defined as +&v4l2-buf-type;. Buffer types changed as mentioned above. A new +memory field of type &v4l2-memory; was +added to distinguish between I/O methods using buffers allocated +by the driver or the application. See for +details. + + + + In &v4l2-buffer; the type +field was properly defined as &v4l2-buf-type;. Buffer types changed as +mentioned above. A field field of type +&v4l2-field; was added to indicate if a buffer contains a top or +bottom field. The old field flags were removed. Since no unadjusted +system time clock was added to the kernel as planned, the +timestamp field changed back from type +stamp_t, an unsigned 64 bit integer expressing the sample time in +nanoseconds, to struct timeval. With the +addition of a second memory mapping method the +offset field moved into union +m, and a new +memory field of type &v4l2-memory; was +added to distinguish between I/O methods. See +for details. + + The V4L2_BUF_REQ_CONTIG +flag was used by the V4L compatibility layer, after changes to this +code it was no longer needed. The +V4L2_BUF_ATTR_DEVICEMEM flag would indicate if +the buffer was indeed allocated in device memory rather than DMA-able +system memory. It was barely useful and so was removed. + + + + In &v4l2-framebuffer; the +base[3] array anticipating double- and +triple-buffering in off-screen video memory, however without defining +a synchronization mechanism, was replaced by a single pointer. The +V4L2_FBUF_CAP_SCALEUP and +V4L2_FBUF_CAP_SCALEDOWN flags were removed. +Applications can determine this capability more accurately using the +new cropping and scaling interface. The +V4L2_FBUF_CAP_CLIPPING flag was replaced by +V4L2_FBUF_CAP_LIST_CLIPPING and +V4L2_FBUF_CAP_BITMAP_CLIPPING. + + + + In &v4l2-clip; the x, +y, width and +height field moved into a +c substructure of type &v4l2-rect;. The +x and y fields +were renamed to left and +top, &ie; offsets to a context dependent +origin. + + + + In &v4l2-window; the x, +y, width and +height field moved into a +w substructure as above. A +field field of type %v4l2-field; was added +to distinguish between field and frame (interlaced) overlay. + + + + The digital zoom interface, including struct +v4l2_zoomcap, struct +v4l2_zoom, +V4L2_ZOOM_NONCAP and +V4L2_ZOOM_WHILESTREAMING was replaced by a new +cropping and scaling interface. The previously unused struct +v4l2_cropcap and +v4l2_crop where redefined for this purpose. +See for details. + + + + In &v4l2-vbi-format; the +SAMPLE_FORMAT field now contains a +four-character-code as used to identify video image formats and +V4L2_PIX_FMT_GREY replaces the +V4L2_VBI_SF_UBYTE define. The +reserved field was extended. + + + + In &v4l2-captureparm; the type of the +timeperframe field changed from unsigned +long to &v4l2-fract;. This allows the accurate expression of multiples +of the NTSC-M frame rate 30000 / 1001. A new field +readbuffers was added to control the driver +behaviour in read I/O mode. + + Similar changes were made to &v4l2-outputparm;. + + + + The struct v4l2_performance +and VIDIOC_G_PERF ioctl were dropped. Except when +using the read/write I/O method, which is +limited anyway, this information is already available to +applications. + + + + The example transformation from RGB to YCbCr color +space in the old V4L2 documentation was inaccurate, this has been +corrected in . + + +
+ +
+ V4L2 2003-06-19 + + + + A new capability flag +V4L2_CAP_RADIO was added for radio devices. Prior +to this change radio devices would identify solely by having exactly one +tuner whose type field reads V4L2_TUNER_RADIO. + + + + An optional driver access priority mechanism was +added, see for details. + + + + The audio input and output interface was found to be +incomplete. + Previously the &VIDIOC-G-AUDIO; +ioctl would enumerate the available audio inputs. An ioctl to +determine the current audio input, if more than one combines with the +current video input, did not exist. So +VIDIOC_G_AUDIO was renamed to +VIDIOC_G_AUDIO_OLD, this ioctl was removed on +Kernel 2.6.39. The &VIDIOC-ENUMAUDIO; ioctl was added to enumerate +audio inputs, while &VIDIOC-G-AUDIO; now reports the current audio +input. + The same changes were made to &VIDIOC-G-AUDOUT; and +&VIDIOC-ENUMAUDOUT;. + Until further the "videodev" module will automatically +translate between the old and new ioctls, but drivers and applications +must be updated to successfully compile again. + + + + The &VIDIOC-OVERLAY; ioctl was incorrectly defined with +write-read parameter. It was changed to write-only, while the write-read +version was renamed to VIDIOC_OVERLAY_OLD. The old +ioctl was removed on Kernel 2.6.39. Until further the "videodev" +kernel module will automatically translate to the new version, so drivers +must be recompiled, but not applications. + + + + incorrectly stated that +clipping rectangles define regions where the video can be seen. +Correct is that clipping rectangles define regions where +no video shall be displayed and so the graphics +surface can be seen. + + + + The &VIDIOC-S-PARM; and &VIDIOC-S-CTRL; ioctls were +defined with write-only parameter, inconsistent with other ioctls +modifying their argument. They were changed to write-read, while a +_OLD suffix was added to the write-only versions. +The old ioctls were removed on Kernel 2.6.39. Drivers and +applications assuming a constant parameter need an update. + + +
+ +
+ V4L2 2003-11-05 + + + In the following pixel +formats were incorrectly transferred from Bill Dirks' V4L2 +specification. Descriptions below refer to bytes in memory, in +ascending address order. + + + + Symbol + In this document prior to revision +0.5 + Corrected + + + + + V4L2_PIX_FMT_RGB24 + B, G, R + R, G, B + + + V4L2_PIX_FMT_BGR24 + R, G, B + B, G, R + + + V4L2_PIX_FMT_RGB32 + B, G, R, X + R, G, B, X + + + V4L2_PIX_FMT_BGR32 + R, G, B, X + B, G, R, X + + + + The +V4L2_PIX_FMT_BGR24 example was always +correct. + In the mapping +of the V4L VIDEO_PALETTE_RGB24 and +VIDEO_PALETTE_RGB32 formats to V4L2 pixel formats +was accordingly corrected. + + + + Unrelated to the fixes above, drivers may still +interpret some V4L2 RGB pixel formats differently. These issues have +yet to be addressed, for details see . + + +
+ +
+ V4L2 in Linux 2.6.6, 2004-05-09 + + + The &VIDIOC-CROPCAP; ioctl was incorrectly defined +with read-only parameter. It is now defined as write-read ioctl, while +the read-only version was renamed to +VIDIOC_CROPCAP_OLD. The old ioctl was removed +on Kernel 2.6.39. + + +
+ +
+ V4L2 in Linux 2.6.8 + + + A new field input (former +reserved[0]) was added to the &v4l2-buffer; +structure. Purpose of this field is to alternate between video inputs +(⪚ cameras) in step with the video capturing process. This function +must be enabled with the new V4L2_BUF_FLAG_INPUT +flag. The flags field is no longer +read-only. + + +
+ +
+ V4L2 spec erratum 2004-08-01 + + + + The return value of the + function was incorrectly documented. + + + + Audio output ioctls end in -AUDOUT, not -AUDIOOUT. + + + + In the Current Audio Input example the +VIDIOC_G_AUDIO ioctl took the wrong +argument. + + + + The documentation of the &VIDIOC-QBUF; and +&VIDIOC-DQBUF; ioctls did not mention the &v4l2-buffer; +memory field. It was also missing from +examples. Also on the VIDIOC_DQBUF page the &EIO; +was not documented. + + +
+ +
+ V4L2 in Linux 2.6.14 + + + A new sliced VBI interface was added. It is documented +in and replaces the interface first +proposed in V4L2 specification 0.8. + + +
+ +
+ V4L2 in Linux 2.6.15 + + + The &VIDIOC-LOG-STATUS; ioctl was added. + + + + New video standards +V4L2_STD_NTSC_443, +V4L2_STD_SECAM_LC, +V4L2_STD_SECAM_DK (a set of SECAM D, K and K1), +and V4L2_STD_ATSC (a set of +V4L2_STD_ATSC_8_VSB and +V4L2_STD_ATSC_16_VSB) were defined. Note the +V4L2_STD_525_60 set now includes +V4L2_STD_NTSC_443. See also . + + + + The VIDIOC_G_COMP and +VIDIOC_S_COMP ioctl were renamed to +VIDIOC_G_MPEGCOMP and +VIDIOC_S_MPEGCOMP respectively. Their argument +was replaced by a struct +v4l2_mpeg_compression pointer. (The +VIDIOC_G_MPEGCOMP and +VIDIOC_S_MPEGCOMP ioctls where removed in Linux +2.6.25.) + + +
+ +
+ V4L2 spec erratum 2005-11-27 + The capture example in +called the &VIDIOC-S-CROP; ioctl without checking if cropping is +supported. In the video standard selection example in + the &VIDIOC-S-STD; call used the wrong +argument type. +
+ +
+ V4L2 spec erratum 2006-01-10 + + + The V4L2_IN_ST_COLOR_KILL flag in +&v4l2-input; not only indicates if the color killer is enabled, but +also if it is active. (The color killer disables color decoding when +it detects no color in the video signal to improve the image +quality.) + + + + &VIDIOC-S-PARM; is a write-read ioctl, not write-only as +stated on its reference page. The ioctl changed in 2003 as noted above. + + +
+ +
+ V4L2 spec erratum 2006-02-03 + + + In &v4l2-captureparm; and &v4l2-outputparm; the +timeperframe field gives the time in +seconds, not microseconds. + + +
+ +
+ V4L2 spec erratum 2006-02-04 + + + The clips field in +&v4l2-window; must point to an array of &v4l2-clip;, not a linked +list, because drivers ignore the struct +v4l2_clip.next +pointer. + + +
+ +
+ V4L2 in Linux 2.6.17 + + + New video standard macros were added: +V4L2_STD_NTSC_M_KR (NTSC M South Korea), and the +sets V4L2_STD_MN, +V4L2_STD_B, V4L2_STD_GH and +V4L2_STD_DK. The +V4L2_STD_NTSC and +V4L2_STD_SECAM sets now include +V4L2_STD_NTSC_M_KR and +V4L2_STD_SECAM_LC respectively. + + + + A new V4L2_TUNER_MODE_LANG1_LANG2 +was defined to record both languages of a bilingual program. The +use of V4L2_TUNER_MODE_STEREO for this purpose +is deprecated now. See the &VIDIOC-G-TUNER; section for +details. + + +
+ +
+ V4L2 spec erratum 2006-09-23 (Draft 0.15) + + + In various places +V4L2_BUF_TYPE_SLICED_VBI_CAPTURE and +V4L2_BUF_TYPE_SLICED_VBI_OUTPUT of the sliced VBI +interface were not mentioned along with other buffer types. + + + + In it was clarified +that the &v4l2-audio; mode field is a flags +field. + + + + did not mention the +sliced VBI and radio capability flags. + + + + In it was +clarified that applications must initialize the tuner +type field of &v4l2-frequency; before +calling &VIDIOC-S-FREQUENCY;. + + + + The reserved array +in &v4l2-requestbuffers; has 2 elements, not 32. + + + + In and the device file names +/dev/vout which never caught on were replaced +by /dev/video. + + + + With Linux 2.6.15 the possible range for VBI device minor +numbers was extended from 224-239 to 224-255. Accordingly device file names +/dev/vbi0 to /dev/vbi31 are +possible now. + + +
+ +
+ V4L2 in Linux 2.6.18 + + + New ioctls &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; +and &VIDIOC-TRY-EXT-CTRLS; were added, a flag to skip unsupported +controls with &VIDIOC-QUERYCTRL;, new control types +V4L2_CTRL_TYPE_INTEGER64 and +V4L2_CTRL_TYPE_CTRL_CLASS (), and new control flags +V4L2_CTRL_FLAG_READ_ONLY, +V4L2_CTRL_FLAG_UPDATE, +V4L2_CTRL_FLAG_INACTIVE and +V4L2_CTRL_FLAG_SLIDER (). See for details. + + +
+ +
+ V4L2 in Linux 2.6.19 + + + In &v4l2-sliced-vbi-cap; a buffer type field was added +replacing a reserved field. Note on architectures where the size of +enum types differs from int types the size of the structure changed. +The &VIDIOC-G-SLICED-VBI-CAP; ioctl was redefined from being read-only +to write-read. Applications must initialize the type field and clear +the reserved fields now. These changes may break the +compatibility with older drivers and applications. + + + + The ioctls &VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; were added. + + + + A new pixel format V4L2_PIX_FMT_RGB444 () was added. + + +
+ +
+ V4L2 spec erratum 2006-10-12 (Draft 0.17) + + + V4L2_PIX_FMT_HM12 () is a YUV 4:2:0, not 4:2:2 format. + + +
+ +
+ V4L2 in Linux 2.6.21 + + + The videodev2.h header file is +now dual licensed under GNU General Public License version two or +later, and under a 3-clause BSD-style license. + + +
+ +
+ V4L2 in Linux 2.6.22 + + + Two new field orders + V4L2_FIELD_INTERLACED_TB and + V4L2_FIELD_INTERLACED_BT were + added. See for details. + + + + Three new clipping/blending methods with a global or +straight or inverted local alpha value were added to the video overlay +interface. See the description of the &VIDIOC-G-FBUF; and +&VIDIOC-S-FBUF; ioctls for details. + A new global_alpha field +was added to v4l2_window, +extending the structure. This may break +compatibility with applications using a struct +v4l2_window directly. However the VIDIOC_G/S/TRY_FMT ioctls, which take a +pointer to a v4l2_format parent +structure with padding bytes at the end, are not affected. + + + + The format of the chromakey +field in &v4l2-window; changed from "host order RGB32" to a pixel +value in the same format as the framebuffer. This may break +compatibility with existing applications. Drivers +supporting the "host order RGB32" format are not known. + + + +
+ +
+ V4L2 in Linux 2.6.24 + + + The pixel formats +V4L2_PIX_FMT_PAL8, +V4L2_PIX_FMT_YUV444, +V4L2_PIX_FMT_YUV555, +V4L2_PIX_FMT_YUV565 and +V4L2_PIX_FMT_YUV32 were added. + + +
+ +
+ V4L2 in Linux 2.6.25 + + + The pixel formats +V4L2_PIX_FMT_Y16 and +V4L2_PIX_FMT_SBGGR16 were added. + + + New controls +V4L2_CID_POWER_LINE_FREQUENCY, +V4L2_CID_HUE_AUTO, +V4L2_CID_WHITE_BALANCE_TEMPERATURE, +V4L2_CID_SHARPNESS and +V4L2_CID_BACKLIGHT_COMPENSATION were added. The +controls V4L2_CID_BLACK_LEVEL, +V4L2_CID_WHITENESS, +V4L2_CID_HCENTER and +V4L2_CID_VCENTER were deprecated. + + + + A Camera controls +class was added, with the new controls +V4L2_CID_EXPOSURE_AUTO, +V4L2_CID_EXPOSURE_ABSOLUTE, +V4L2_CID_EXPOSURE_AUTO_PRIORITY, +V4L2_CID_PAN_RELATIVE, +V4L2_CID_TILT_RELATIVE, +V4L2_CID_PAN_RESET, +V4L2_CID_TILT_RESET, +V4L2_CID_PAN_ABSOLUTE, +V4L2_CID_TILT_ABSOLUTE, +V4L2_CID_FOCUS_ABSOLUTE, +V4L2_CID_FOCUS_RELATIVE and +V4L2_CID_FOCUS_AUTO. + + + The VIDIOC_G_MPEGCOMP and +VIDIOC_S_MPEGCOMP ioctls, which were superseded +by the extended controls +interface in Linux 2.6.18, where finally removed from the +videodev2.h header file. + + +
+ +
+ V4L2 in Linux 2.6.26 + + + The pixel formats +V4L2_PIX_FMT_Y16 and +V4L2_PIX_FMT_SBGGR16 were added. + + + Added user controls +V4L2_CID_CHROMA_AGC and +V4L2_CID_COLOR_KILLER. + + +
+ +
+ V4L2 in Linux 2.6.27 + + + The &VIDIOC-S-HW-FREQ-SEEK; ioctl and the +V4L2_CAP_HW_FREQ_SEEK capability were added. + + + The pixel formats +V4L2_PIX_FMT_YVYU, +V4L2_PIX_FMT_PCA501, +V4L2_PIX_FMT_PCA505, +V4L2_PIX_FMT_PCA508, +V4L2_PIX_FMT_PCA561, +V4L2_PIX_FMT_SGBRG8, +V4L2_PIX_FMT_PAC207 and +V4L2_PIX_FMT_PJPG were added. + + +
+ +
+ V4L2 in Linux 2.6.28 + + + Added V4L2_MPEG_AUDIO_ENCODING_AAC and +V4L2_MPEG_AUDIO_ENCODING_AC3 MPEG audio encodings. + + + Added V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC MPEG +video encoding. + + + The pixel formats +V4L2_PIX_FMT_SGRBG10 and +V4L2_PIX_FMT_SGRBG10DPCM8 were added. + + +
+ +
+ V4L2 in Linux 2.6.29 + + + The VIDIOC_G_CHIP_IDENT ioctl was renamed +to VIDIOC_G_CHIP_IDENT_OLD and &VIDIOC-DBG-G-CHIP-IDENT; +was introduced in its place. The old struct v4l2_chip_ident +was renamed to v4l2_chip_ident_old. + + + The pixel formats +V4L2_PIX_FMT_VYUY, +V4L2_PIX_FMT_NV16 and +V4L2_PIX_FMT_NV61 were added. + + + Added camera controls +V4L2_CID_ZOOM_ABSOLUTE, +V4L2_CID_ZOOM_RELATIVE, +V4L2_CID_ZOOM_CONTINUOUS and +V4L2_CID_PRIVACY. + + +
+
+ V4L2 in Linux 2.6.30 + + + New control flag V4L2_CTRL_FLAG_WRITE_ONLY was added. + + + New control V4L2_CID_COLORFX was added. + + +
+
+ V4L2 in Linux 2.6.32 + + + In order to be easier to compare a V4L2 API and a kernel +version, now V4L2 API is numbered using the Linux Kernel version numeration. + + + Finalized the RDS capture API. See for +more information. + + + Added new capabilities for modulators and RDS encoders. + + + Add description for libv4l API. + + + Added support for string controls via new type V4L2_CTRL_TYPE_STRING. + + + Added V4L2_CID_BAND_STOP_FILTER documentation. + + + Added FM Modulator (FM TX) Extended Control Class: V4L2_CTRL_CLASS_FM_TX and their Control IDs. + + + Added Remote Controller chapter, describing the default Remote Controller mapping for media devices. + + +
+
+ V4L2 in Linux 2.6.33 + + + Added support for Digital Video timings in order to support HDTV receivers and transmitters. + + +
+
+ V4L2 in Linux 2.6.34 + + + Added +V4L2_CID_IRIS_ABSOLUTE and +V4L2_CID_IRIS_RELATIVE controls to the + Camera controls class. + + + +
+
+ V4L2 in Linux 2.6.37 + + + Remove the vtx (videotext/teletext) API. This API was no longer +used and no hardware exists to verify the API. Nor were any userspace applications found +that used it. It was originally scheduled for removal in 2.6.35. + + + +
+
+ V4L2 in Linux 2.6.39 + + + The old VIDIOC_*_OLD symbols and V4L1 support were removed. + + + Multi-planar API added. Does not affect the compatibility of + current drivers and applications. See + multi-planar API + for details. + + +
+ +
+ Relation of V4L2 to other Linux multimedia APIs + +
+ X Video Extension + + The X Video Extension (abbreviated XVideo or just Xv) is +an extension of the X Window system, implemented for example by the +XFree86 project. Its scope is similar to V4L2, an API to video capture +and output devices for X clients. Xv allows applications to display +live video in a window, send window contents to a TV output, and +capture or output still images in XPixmaps + This is not implemented in XFree86. + . With their implementation XFree86 makes the +extension available across many operating systems and +architectures. + + Because the driver is embedded into the X server Xv has a +number of advantages over the V4L2 video +overlay interface. The driver can easily determine the overlay +target, &ie; visible graphics memory or off-screen buffers for a +destructive overlay. It can program the RAMDAC for a non-destructive +overlay, scaling or color-keying, or the clipping functions of the +video capture hardware, always in sync with drawing operations or +windows moving or changing their stacking order. + + To combine the advantages of Xv and V4L a special Xv +driver exists in XFree86 and XOrg, just programming any overlay capable +Video4Linux device it finds. To enable it +/etc/X11/XF86Config must contain these lines: + +Section "Module" + Load "v4l" +EndSection + + As of XFree86 4.2 this driver still supports only V4L +ioctls, however it should work just fine with all V4L2 devices through +the V4L2 backward-compatibility layer. Since V4L2 permits multiple +opens it is possible (if supported by the V4L2 driver) to capture +video while an X client requested video overlay. Restrictions of +simultaneous capturing and overlay are discussed in apply. + + Only marginally related to V4L2, XFree86 extended Xv to +support hardware YUV to RGB conversion and scaling for faster video +playback, and added an interface to MPEG-2 decoding hardware. This API +is useful to display images captured with V4L2 devices. +
+ +
+ Digital Video + + V4L2 does not support digital terrestrial, cable or +satellite broadcast. A separate project aiming at digital receivers +exists. You can find its homepage at http://linuxtv.org. The Linux DVB API +has no connection to the V4L2 API except that drivers for hybrid +hardware may support both. +
+ +
+ Audio Interfaces + + [to do - OSS/ALSA] +
+
+ +
+ Experimental API Elements + + The following V4L2 API elements are currently experimental +and may change in the future. + + + + Video Output Overlay (OSD) Interface, . + + + V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY, + &v4l2-buf-type;, . + + + V4L2_CAP_VIDEO_OUTPUT_OVERLAY, +&VIDIOC-QUERYCAP; ioctl, . + + + &VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; ioctls. + + + &VIDIOC-G-ENC-INDEX; ioctl. + + + &VIDIOC-ENCODER-CMD; and &VIDIOC-TRY-ENCODER-CMD; +ioctls. + + + &VIDIOC-DBG-G-REGISTER; and &VIDIOC-DBG-S-REGISTER; +ioctls. + + + &VIDIOC-DBG-G-CHIP-IDENT; ioctl. + + +
+ +
+ Obsolete API Elements + + The following V4L2 API elements were superseded by new +interfaces and should not be implemented in new drivers. + + + + VIDIOC_G_MPEGCOMP and +VIDIOC_S_MPEGCOMP ioctls. Use Extended Controls, +. + + +
+
+ + diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml new file mode 100644 index 00000000000..a920ee80f64 --- /dev/null +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -0,0 +1,2103 @@ +
+ User Controls + + Devices typically have a number of user-settable controls +such as brightness, saturation and so on, which would be presented to +the user on a graphical user interface. But, different devices +will have different controls available, and furthermore, the range of +possible values, and the default value will vary from device to +device. The control ioctls provide the information and a mechanism to +create a nice user interface for these controls that will work +correctly with any device. + + All controls are accessed using an ID value. V4L2 defines +several IDs for specific purposes. Drivers can also implement their +own custom controls using V4L2_CID_PRIVATE_BASE +and higher values. The pre-defined control IDs have the prefix +V4L2_CID_, and are listed in . The ID is used when querying the attributes of +a control, and when getting or setting the current value. + + Generally applications should present controls to the user +without assumptions about their purpose. Each control comes with a +name string the user is supposed to understand. When the purpose is +non-intuitive the driver writer should provide a user manual, a user +interface plug-in or a driver specific panel application. Predefined +IDs were introduced to change a few controls programmatically, for +example to mute a device during a channel switch. + + Drivers may enumerate different controls after switching +the current video input or output, tuner or modulator, or audio input +or output. Different in the sense of other bounds, another default and +current value, step size or other menu items. A control with a certain +custom ID can also change name and +type. + It will be more convenient for applications if drivers +make use of the V4L2_CTRL_FLAG_DISABLED flag, but +that was never required. + Control values are stored globally, they do not +change when switching except to stay within the reported bounds. They +also do not change ⪚ when the device is opened or closed, when the +tuner radio frequency is changed or generally never without +application request. Since V4L2 specifies no event mechanism, panel +applications intended to cooperate with other panel applications (be +they built into a larger application, as a TV viewer) may need to +regularly poll control values to update their user +interface. + Applications could call an ioctl to request events. +After another process called &VIDIOC-S-CTRL; or another ioctl changing +shared properties the &func-select; function would indicate +readability until any ioctl (querying the properties) is +called. + + + + Control IDs + + &cs-def; + + + ID + Type + Description + + + + + V4L2_CID_BASE + + First predefined ID, equal to +V4L2_CID_BRIGHTNESS. + + + V4L2_CID_USER_BASE + + Synonym of V4L2_CID_BASE. + + + V4L2_CID_BRIGHTNESS + integer + Picture brightness, or more precisely, the black +level. + + + V4L2_CID_CONTRAST + integer + Picture contrast or luma gain. + + + V4L2_CID_SATURATION + integer + Picture color saturation or chroma gain. + + + V4L2_CID_HUE + integer + Hue or color balance. + + + V4L2_CID_AUDIO_VOLUME + integer + Overall audio volume. Note some drivers also +provide an OSS or ALSA mixer interface. + + + V4L2_CID_AUDIO_BALANCE + integer + Audio stereo balance. Minimum corresponds to all +the way left, maximum to right. + + + V4L2_CID_AUDIO_BASS + integer + Audio bass adjustment. + + + V4L2_CID_AUDIO_TREBLE + integer + Audio treble adjustment. + + + V4L2_CID_AUDIO_MUTE + boolean + Mute audio, &ie; set the volume to zero, however +without affecting V4L2_CID_AUDIO_VOLUME. Like +ALSA drivers, V4L2 drivers must mute at load time to avoid excessive +noise. Actually the entire device should be reset to a low power +consumption state. + + + V4L2_CID_AUDIO_LOUDNESS + boolean + Loudness mode (bass boost). + + + V4L2_CID_BLACK_LEVEL + integer + Another name for brightness (not a synonym of +V4L2_CID_BRIGHTNESS). This control is deprecated +and should not be used in new drivers and applications. + + + V4L2_CID_AUTO_WHITE_BALANCE + boolean + Automatic white balance (cameras). + + + V4L2_CID_DO_WHITE_BALANCE + button + This is an action control. When set (the value is +ignored), the device will do a white balance and then hold the current +setting. Contrast this with the boolean +V4L2_CID_AUTO_WHITE_BALANCE, which, when +activated, keeps adjusting the white balance. + + + V4L2_CID_RED_BALANCE + integer + Red chroma balance. + + + V4L2_CID_BLUE_BALANCE + integer + Blue chroma balance. + + + V4L2_CID_GAMMA + integer + Gamma adjust. + + + V4L2_CID_WHITENESS + integer + Whiteness for grey-scale devices. This is a synonym +for V4L2_CID_GAMMA. This control is deprecated +and should not be used in new drivers and applications. + + + V4L2_CID_EXPOSURE + integer + Exposure (cameras). [Unit?] + + + V4L2_CID_AUTOGAIN + boolean + Automatic gain/exposure control. + + + V4L2_CID_GAIN + integer + Gain control. + + + V4L2_CID_HFLIP + boolean + Mirror the picture horizontally. + + + V4L2_CID_VFLIP + boolean + Mirror the picture vertically. + + + V4L2_CID_HCENTER_DEPRECATED (formerly V4L2_CID_HCENTER) + integer + Horizontal image centering. This control is +deprecated. New drivers and applications should use the Camera class controls +V4L2_CID_PAN_ABSOLUTE, +V4L2_CID_PAN_RELATIVE and +V4L2_CID_PAN_RESET instead. + + + V4L2_CID_VCENTER_DEPRECATED + (formerly V4L2_CID_VCENTER) + integer + Vertical image centering. Centering is intended to +physically adjust cameras. For image cropping see +, for clipping . This +control is deprecated. New drivers and applications should use the +Camera class controls +V4L2_CID_TILT_ABSOLUTE, +V4L2_CID_TILT_RELATIVE and +V4L2_CID_TILT_RESET instead. + + + V4L2_CID_POWER_LINE_FREQUENCY + enum + Enables a power line frequency filter to avoid +flicker. Possible values for enum v4l2_power_line_frequency are: +V4L2_CID_POWER_LINE_FREQUENCY_DISABLED (0), +V4L2_CID_POWER_LINE_FREQUENCY_50HZ (1) and +V4L2_CID_POWER_LINE_FREQUENCY_60HZ (2). + + + V4L2_CID_HUE_AUTO + boolean + Enables automatic hue control by the device. The +effect of setting V4L2_CID_HUE while automatic +hue control is enabled is undefined, drivers should ignore such +request. + + + V4L2_CID_WHITE_BALANCE_TEMPERATURE + integer + This control specifies the white balance settings +as a color temperature in Kelvin. A driver should have a minimum of +2800 (incandescent) to 6500 (daylight). For more information about +color temperature see Wikipedia. + + + V4L2_CID_SHARPNESS + integer + Adjusts the sharpness filters in a camera. The +minimum value disables the filters, higher values give a sharper +picture. + + + V4L2_CID_BACKLIGHT_COMPENSATION + integer + Adjusts the backlight compensation in a camera. The +minimum value disables backlight compensation. + + + V4L2_CID_CHROMA_AGC + boolean + Chroma automatic gain control. + + + V4L2_CID_CHROMA_GAIN + integer + Adjusts the Chroma gain control (for use when chroma AGC + is disabled). + + + V4L2_CID_COLOR_KILLER + boolean + Enable the color killer (&ie; force a black & white image in case of a weak video signal). + + + V4L2_CID_COLORFX + enum + Selects a color effect. Possible values for +enum v4l2_colorfx are: +V4L2_COLORFX_NONE (0), +V4L2_COLORFX_BW (1), +V4L2_COLORFX_SEPIA (2), +V4L2_COLORFX_NEGATIVE (3), +V4L2_COLORFX_EMBOSS (4), +V4L2_COLORFX_SKETCH (5), +V4L2_COLORFX_SKY_BLUE (6), +V4L2_COLORFX_GRASS_GREEN (7), +V4L2_COLORFX_SKIN_WHITEN (8) and +V4L2_COLORFX_VIVID (9). + + + V4L2_CID_ROTATE + integer + Rotates the image by specified angle. Common angles are 90, + 270 and 180. Rotating the image to 90 and 270 will reverse the height + and width of the display window. It is necessary to set the new height and + width of the picture using the &VIDIOC-S-FMT; ioctl according to + the rotation angle selected. + + + V4L2_CID_BG_COLOR + integer + Sets the background color on the current output device. + Background color needs to be specified in the RGB24 format. The + supplied 32 bit value is interpreted as bits 0-7 Red color information, + bits 8-15 Green color information, bits 16-23 Blue color + information and bits 24-31 must be zero. + + + V4L2_CID_ILLUMINATORS_1 + V4L2_CID_ILLUMINATORS_2 + boolean + Switch on or off the illuminator 1 or 2 of the device + (usually a microscope). + + + V4L2_CID_LASTP1 + + End of the predefined control IDs (currently +V4L2_CID_ILLUMINATORS_2 + 1). + + + V4L2_CID_PRIVATE_BASE + + ID of the first custom (driver specific) control. +Applications depending on particular custom controls should check the +driver name and version, see . + + + +
+ + Applications can enumerate the available controls with the +&VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls, get and set a +control value with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls. +Drivers must implement VIDIOC_QUERYCTRL, +VIDIOC_G_CTRL and +VIDIOC_S_CTRL when the device has one or more +controls, VIDIOC_QUERYMENU when it has one or +more menu type controls. + + + Enumerating all controls + + +&v4l2-queryctrl; queryctrl; +&v4l2-querymenu; querymenu; + +static void +enumerate_menu (void) +{ + printf (" Menu items:\n"); + + memset (&querymenu, 0, sizeof (querymenu)); + querymenu.id = queryctrl.id; + + for (querymenu.index = queryctrl.minimum; + querymenu.index <= queryctrl.maximum; + querymenu.index++) { + if (0 == ioctl (fd, &VIDIOC-QUERYMENU;, &querymenu)) { + printf (" %s\n", querymenu.name); + } + } +} + +memset (&queryctrl, 0, sizeof (queryctrl)); + +for (queryctrl.id = V4L2_CID_BASE; + queryctrl.id < V4L2_CID_LASTP1; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + continue; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} + +for (queryctrl.id = V4L2_CID_PRIVATE_BASE;; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + break; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} + + + + + Changing controls + + +&v4l2-queryctrl; queryctrl; +&v4l2-control; control; + +memset (&queryctrl, 0, sizeof (queryctrl)); +queryctrl.id = V4L2_CID_BRIGHTNESS; + +if (-1 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (errno != EINVAL) { + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } else { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); + } +} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); +} else { + memset (&control, 0, sizeof (control)); + control.id = V4L2_CID_BRIGHTNESS; + control.value = queryctrl.default_value; + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control)) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +} + +memset (&control, 0, sizeof (control)); +control.id = V4L2_CID_CONTRAST; + +if (0 == ioctl (fd, &VIDIOC-G-CTRL;, &control)) { + control.value += 1; + + /* The driver may clamp the value or return ERANGE, ignored here */ + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control) + && errno != ERANGE) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +/* Ignore if V4L2_CID_CONTRAST is unsupported */ +} else if (errno != EINVAL) { + perror ("VIDIOC_G_CTRL"); + exit (EXIT_FAILURE); +} + +control.id = V4L2_CID_AUDIO_MUTE; +control.value = TRUE; /* silence */ + +/* Errors ignored */ +ioctl (fd, VIDIOC_S_CTRL, &control); + + +
+ +
+ Extended Controls + +
+ Introduction + + The control mechanism as originally designed was meant +to be used for user settings (brightness, saturation, etc). However, +it turned out to be a very useful model for implementing more +complicated driver APIs where each driver implements only a subset of +a larger API. + + The MPEG encoding API was the driving force behind +designing and implementing this extended control mechanism: the MPEG +standard is quite large and the currently supported hardware MPEG +encoders each only implement a subset of this standard. Further more, +many parameters relating to how the video is encoded into an MPEG +stream are specific to the MPEG encoding chip since the MPEG standard +only defines the format of the resulting MPEG stream, not how the +video is actually encoded into that format. + + Unfortunately, the original control API lacked some +features needed for these new uses and so it was extended into the +(not terribly originally named) extended control API. + + Even though the MPEG encoding API was the first effort +to use the Extended Control API, nowadays there are also other classes +of Extended Controls, such as Camera Controls and FM Transmitter Controls. +The Extended Controls API as well as all Extended Controls classes are +described in the following text. +
+ +
+ The Extended Control API + + Three new ioctls are available: &VIDIOC-G-EXT-CTRLS;, +&VIDIOC-S-EXT-CTRLS; and &VIDIOC-TRY-EXT-CTRLS;. These ioctls act on +arrays of controls (as opposed to the &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls that act on a single control). This is needed +since it is often required to atomically change several controls at +once. + + Each of the new ioctls expects a pointer to a +&v4l2-ext-controls;. This structure contains a pointer to the control +array, a count of the number of controls in that array and a control +class. Control classes are used to group similar controls into a +single class. For example, control class +V4L2_CTRL_CLASS_USER contains all user controls +(&ie; all controls that can also be set using the old +VIDIOC_S_CTRL ioctl). Control class +V4L2_CTRL_CLASS_MPEG contains all controls +relating to MPEG encoding, etc. + + All controls in the control array must belong to the +specified control class. An error is returned if this is not the +case. + + It is also possible to use an empty control array (count +== 0) to check whether the specified control class is +supported. + + The control array is a &v4l2-ext-control; array. The +v4l2_ext_control structure is very similar to +&v4l2-control;, except for the fact that it also allows for 64-bit +values and pointers to be passed. + + It is important to realize that due to the flexibility of +controls it is necessary to check whether the control you want to set +actually is supported in the driver and what the valid range of values +is. So use the &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls to +check this. Also note that it is possible that some of the menu +indices in a control of type V4L2_CTRL_TYPE_MENU +may not be supported (VIDIOC_QUERYMENU will +return an error). A good example is the list of supported MPEG audio +bitrates. Some drivers only support one or two bitrates, others +support a wider range. +
+ +
+ Enumerating Extended Controls + + The recommended way to enumerate over the extended +controls is by using &VIDIOC-QUERYCTRL; in combination with the +V4L2_CTRL_FLAG_NEXT_CTRL flag: + + + +&v4l2-queryctrl; qctrl; + +qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; +} + + + + The initial control ID is set to 0 ORed with the +V4L2_CTRL_FLAG_NEXT_CTRL flag. The +VIDIOC_QUERYCTRL ioctl will return the first +control with a higher ID than the specified one. When no such controls +are found an error is returned. + + If you want to get all controls within a specific control +class, then you can set the initial +qctrl.id value to the control class and add +an extra check to break out of the loop when a control of another +control class is found: + + + +qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + if (V4L2_CTRL_ID2CLASS (qctrl.id) != V4L2_CTRL_CLASS_MPEG) + break; + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; + } + + + + The 32-bit qctrl.id value is +subdivided into three bit ranges: the top 4 bits are reserved for +flags (⪚ V4L2_CTRL_FLAG_NEXT_CTRL) and are not +actually part of the ID. The remaining 28 bits form the control ID, of +which the most significant 12 bits define the control class and the +least significant 16 bits identify the control within the control +class. It is guaranteed that these last 16 bits are always non-zero +for controls. The range of 0x1000 and up are reserved for +driver-specific controls. The macro +V4L2_CTRL_ID2CLASS(id) returns the control class +ID based on a control ID. + + If the driver does not support extended controls, then +VIDIOC_QUERYCTRL will fail when used in +combination with V4L2_CTRL_FLAG_NEXT_CTRL. In +that case the old method of enumerating control should be used (see +1.8). But if it is supported, then it is guaranteed to enumerate over +all controls, including driver-private controls. +
+ +
+ Creating Control Panels + + It is possible to create control panels for a graphical +user interface where the user can select the various controls. +Basically you will have to iterate over all controls using the method +described above. Each control class starts with a control of type +V4L2_CTRL_TYPE_CTRL_CLASS. +VIDIOC_QUERYCTRL will return the name of this +control class which can be used as the title of a tab page within a +control panel. + + The flags field of &v4l2-queryctrl; also contains hints on +the behavior of the control. See the &VIDIOC-QUERYCTRL; documentation +for more details. +
+ +
+ MPEG Control Reference + + Below all controls within the MPEG control class are +described. First the generic controls, then controls specific for +certain hardware. + +
+ Generic MPEG Controls + + + MPEG Control IDs + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_MPEG_CLASS  + class + The MPEG class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class. This description can be used as the +caption of a Tab page in a GUI, for example. + + + + V4L2_CID_MPEG_STREAM_TYPE  + enum v4l2_mpeg_stream_type + The MPEG-1, -2 or -4 +output stream type. One cannot assume anything here. Each hardware +MPEG encoder tends to support different subsets of the available MPEG +stream types. The currently defined stream types are: + + + + + + V4L2_MPEG_STREAM_TYPE_MPEG2_PS  + MPEG-2 program stream + + + V4L2_MPEG_STREAM_TYPE_MPEG2_TS  + MPEG-2 transport stream + + + V4L2_MPEG_STREAM_TYPE_MPEG1_SS  + MPEG-1 system stream + + + V4L2_MPEG_STREAM_TYPE_MPEG2_DVD  + MPEG-2 DVD-compatible stream + + + V4L2_MPEG_STREAM_TYPE_MPEG1_VCD  + MPEG-1 VCD-compatible stream + + + V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD  + MPEG-2 SVCD-compatible stream + + + + + + + V4L2_CID_MPEG_STREAM_PID_PMT  + integer + Program Map Table +Packet ID for the MPEG transport stream (default 16) + + + + V4L2_CID_MPEG_STREAM_PID_AUDIO  + integer + Audio Packet ID for +the MPEG transport stream (default 256) + + + + V4L2_CID_MPEG_STREAM_PID_VIDEO  + integer + Video Packet ID for +the MPEG transport stream (default 260) + + + + V4L2_CID_MPEG_STREAM_PID_PCR  + integer + Packet ID for the +MPEG transport stream carrying PCR fields (default 259) + + + + V4L2_CID_MPEG_STREAM_PES_ID_AUDIO  + integer + Audio ID for MPEG +PES + + + + V4L2_CID_MPEG_STREAM_PES_ID_VIDEO  + integer + Video ID for MPEG +PES + + + + V4L2_CID_MPEG_STREAM_VBI_FMT  + enum v4l2_mpeg_stream_vbi_fmt + Some cards can embed +VBI data (⪚ Closed Caption, Teletext) into the MPEG stream. This +control selects whether VBI data should be embedded, and if so, what +embedding method should be used. The list of possible VBI formats +depends on the driver. The currently defined VBI format types +are: + + + + + + V4L2_MPEG_STREAM_VBI_FMT_NONE  + No VBI in the MPEG stream + + + V4L2_MPEG_STREAM_VBI_FMT_IVTV  + VBI in private packets, IVTV format (documented +in the kernel sources in the file Documentation/video4linux/cx2341x/README.vbi) + + + + + + + V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ  + enum v4l2_mpeg_audio_sampling_freq + MPEG Audio sampling +frequency. Possible values are: + + + + + + V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100  + 44.1 kHz + + + V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000  + 48 kHz + + + V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000  + 32 kHz + + + + + + + V4L2_CID_MPEG_AUDIO_ENCODING  + enum v4l2_mpeg_audio_encoding + MPEG Audio encoding. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_ENCODING_LAYER_1  + MPEG-1/2 Layer I encoding + + + V4L2_MPEG_AUDIO_ENCODING_LAYER_2  + MPEG-1/2 Layer II encoding + + + V4L2_MPEG_AUDIO_ENCODING_LAYER_3  + MPEG-1/2 Layer III encoding + + + V4L2_MPEG_AUDIO_ENCODING_AAC  + MPEG-2/4 AAC (Advanced Audio Coding) + + + V4L2_MPEG_AUDIO_ENCODING_AC3  + AC-3 aka ATSC A/52 encoding + + + + + + + V4L2_CID_MPEG_AUDIO_L1_BITRATE  + enum v4l2_mpeg_audio_l1_bitrate + MPEG-1/2 Layer I bitrate. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_L1_BITRATE_32K  + 32 kbit/s + + V4L2_MPEG_AUDIO_L1_BITRATE_64K  + 64 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_96K  + 96 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_128K  + 128 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_160K  + 160 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_192K  + 192 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_224K  + 224 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_256K  + 256 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_288K  + 288 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_320K  + 320 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_352K  + 352 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_384K  + 384 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_416K  + 416 kbit/s + + + V4L2_MPEG_AUDIO_L1_BITRATE_448K  + 448 kbit/s + + + + + + + V4L2_CID_MPEG_AUDIO_L2_BITRATE  + enum v4l2_mpeg_audio_l2_bitrate + MPEG-1/2 Layer II bitrate. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_L2_BITRATE_32K  + 32 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_48K  + 48 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_56K  + 56 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_64K  + 64 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_80K  + 80 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_96K  + 96 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_112K  + 112 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_128K  + 128 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_160K  + 160 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_192K  + 192 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_224K  + 224 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_256K  + 256 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_320K  + 320 kbit/s + + + V4L2_MPEG_AUDIO_L2_BITRATE_384K  + 384 kbit/s + + + + + + + V4L2_CID_MPEG_AUDIO_L3_BITRATE  + enum v4l2_mpeg_audio_l3_bitrate + MPEG-1/2 Layer III bitrate. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_L3_BITRATE_32K  + 32 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_40K  + 40 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_48K  + 48 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_56K  + 56 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_64K  + 64 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_80K  + 80 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_96K  + 96 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_112K  + 112 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_128K  + 128 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_160K  + 160 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_192K  + 192 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_224K  + 224 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_256K  + 256 kbit/s + + + V4L2_MPEG_AUDIO_L3_BITRATE_320K  + 320 kbit/s + + + + + + + V4L2_CID_MPEG_AUDIO_AAC_BITRATE  + integer + AAC bitrate in bits per second. + + + + V4L2_CID_MPEG_AUDIO_AC3_BITRATE  + enum v4l2_mpeg_audio_ac3_bitrate + AC-3 bitrate. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_AC3_BITRATE_32K  + 32 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_40K  + 40 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_48K  + 48 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_56K  + 56 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_64K  + 64 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_80K  + 80 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_96K  + 96 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_112K  + 112 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_128K  + 128 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_160K  + 160 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_192K  + 192 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_224K  + 224 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_256K  + 256 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_320K  + 320 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_384K  + 384 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_448K  + 448 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_512K  + 512 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_576K  + 576 kbit/s + + + V4L2_MPEG_AUDIO_AC3_BITRATE_640K  + 640 kbit/s + + + + + + + V4L2_CID_MPEG_AUDIO_MODE  + enum v4l2_mpeg_audio_mode + MPEG Audio mode. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_MODE_STEREO  + Stereo + + + V4L2_MPEG_AUDIO_MODE_JOINT_STEREO  + Joint Stereo + + + V4L2_MPEG_AUDIO_MODE_DUAL  + Bilingual + + + V4L2_MPEG_AUDIO_MODE_MONO  + Mono + + + + + + + V4L2_CID_MPEG_AUDIO_MODE_EXTENSION  + enum v4l2_mpeg_audio_mode_extension + Joint Stereo +audio mode extension. In Layer I and II they indicate which subbands +are in intensity stereo. All other subbands are coded in stereo. Layer +III is not (yet) supported. Possible values +are: + + + + + + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4  + Subbands 4-31 in intensity stereo + + + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8  + Subbands 8-31 in intensity stereo + + + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12  + Subbands 12-31 in intensity stereo + + + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16  + Subbands 16-31 in intensity stereo + + + + + + + V4L2_CID_MPEG_AUDIO_EMPHASIS  + enum v4l2_mpeg_audio_emphasis + Audio Emphasis. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_EMPHASIS_NONE  + None + + + V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS  + 50/15 microsecond emphasis + + + V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17  + CCITT J.17 + + + + + + + V4L2_CID_MPEG_AUDIO_CRC  + enum v4l2_mpeg_audio_crc + CRC method. Possible +values are: + + + + + + V4L2_MPEG_AUDIO_CRC_NONE  + None + + + V4L2_MPEG_AUDIO_CRC_CRC16  + 16 bit parity check + + + + + + + V4L2_CID_MPEG_AUDIO_MUTE  + boolean + Mutes the audio when +capturing. This is not done by muting audio hardware, which can still +produce a slight hiss, but in the encoder itself, guaranteeing a fixed +and reproducible audio bitstream. 0 = unmuted, 1 = muted. + + + + V4L2_CID_MPEG_VIDEO_ENCODING  + enum v4l2_mpeg_video_encoding + MPEG Video encoding +method. Possible values are: + + + + + + V4L2_MPEG_VIDEO_ENCODING_MPEG_1  + MPEG-1 Video encoding + + + V4L2_MPEG_VIDEO_ENCODING_MPEG_2  + MPEG-2 Video encoding + + + V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC  + MPEG-4 AVC (H.264) Video encoding + + + + + + + V4L2_CID_MPEG_VIDEO_ASPECT  + enum v4l2_mpeg_video_aspect + Video aspect. +Possible values are: + + + + + + V4L2_MPEG_VIDEO_ASPECT_1x1  + + + V4L2_MPEG_VIDEO_ASPECT_4x3  + + + V4L2_MPEG_VIDEO_ASPECT_16x9  + + + V4L2_MPEG_VIDEO_ASPECT_221x100  + + + + + + + V4L2_CID_MPEG_VIDEO_B_FRAMES  + integer + Number of B-Frames +(default 2) + + + + V4L2_CID_MPEG_VIDEO_GOP_SIZE  + integer + GOP size (default +12) + + + + V4L2_CID_MPEG_VIDEO_GOP_CLOSURE  + boolean + GOP closure (default +1) + + + + V4L2_CID_MPEG_VIDEO_PULLDOWN  + boolean + Enable 3:2 pulldown +(default 0) + + + + V4L2_CID_MPEG_VIDEO_BITRATE_MODE  + enum v4l2_mpeg_video_bitrate_mode + Video bitrate mode. +Possible values are: + + + + + + V4L2_MPEG_VIDEO_BITRATE_MODE_VBR  + Variable bitrate + + + V4L2_MPEG_VIDEO_BITRATE_MODE_CBR  + Constant bitrate + + + + + + + V4L2_CID_MPEG_VIDEO_BITRATE  + integer + Video bitrate in bits +per second. + + + + V4L2_CID_MPEG_VIDEO_BITRATE_PEAK  + integer + Peak video bitrate in +bits per second. Must be larger or equal to the average video bitrate. +It is ignored if the video bitrate mode is set to constant +bitrate. + + + + V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION  + integer + For every captured +frame, skip this many subsequent frames (default 0). + + + + V4L2_CID_MPEG_VIDEO_MUTE  + boolean + + "Mutes" the video to a +fixed color when capturing. This is useful for testing, to produce a +fixed video bitstream. 0 = unmuted, 1 = muted. + + + + V4L2_CID_MPEG_VIDEO_MUTE_YUV  + integer + Sets the "mute" color +of the video. The supplied 32-bit integer is interpreted as follows (bit +0 = least significant bit): + + + + + + Bit 0:7 + V chrominance information + + + Bit 8:15 + U chrominance information + + + Bit 16:23 + Y luminance information + + + Bit 24:31 + Must be zero. + + + + + + +
+
+ +
+ CX2341x MPEG Controls + + The following MPEG class controls deal with MPEG +encoding settings that are specific to the Conexant CX23415 and +CX23416 MPEG encoding chips. + + + CX2341x Control IDs + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE  + enum v4l2_mpeg_cx2341x_video_spatial_filter_mode + Sets the Spatial +Filter mode (default MANUAL). Possible values +are: + + + + + + V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL  + Choose the filter manually + + + V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO  + Choose the filter automatically + + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER  + integer (0-15) + The setting for the +Spatial Filter. 0 = off, 15 = maximum. (Default is 0.) + + + + V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE  + enum v4l2_mpeg_cx2341x_video_luma_spatial_filter_type + Select the algorithm +to use for the Luma Spatial Filter (default +1D_HOR). Possible values: + + + + + + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF  + No filter + + + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR  + One-dimensional horizontal + + + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT  + One-dimensional vertical + + + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE  + Two-dimensional separable + + + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE  + Two-dimensional symmetrical +non-separable + + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE  + enum v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type + Select the algorithm +for the Chroma Spatial Filter (default 1D_HOR). +Possible values are: + + + + + + V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF  + No filter + + + V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR  + One-dimensional horizontal + + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE  + enum v4l2_mpeg_cx2341x_video_temporal_filter_mode + Sets the Temporal +Filter mode (default MANUAL). Possible values +are: + + + + + + V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL  + Choose the filter manually + + + V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO  + Choose the filter automatically + + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER  + integer (0-31) + The setting for the +Temporal Filter. 0 = off, 31 = maximum. (Default is 8 for full-scale +capturing and 0 for scaled capturing.) + + + + V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE  + enum v4l2_mpeg_cx2341x_video_median_filter_type + Median Filter Type +(default OFF). Possible values are: + + + + + + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF  + No filter + + + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR  + Horizontal filter + + + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT  + Vertical filter + + + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT  + Horizontal and vertical filter + + + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG  + Diagonal filter + + + + + + + V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM  + integer (0-255) + Threshold above which +the luminance median filter is enabled (default 0) + + + + V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP  + integer (0-255) + Threshold below which +the luminance median filter is enabled (default 255) + + + + V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM  + integer (0-255) + Threshold above which +the chroma median filter is enabled (default 0) + + + + V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP  + integer (0-255) + Threshold below which +the chroma median filter is enabled (default 255) + + + + V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS  + boolean + + The CX2341X MPEG encoder +can insert one empty MPEG-2 PES packet into the stream between every +four video frames. The packet size is 2048 bytes, including the +packet_start_code_prefix and stream_id fields. The stream_id is 0xBF +(private stream 2). The payload consists of 0x00 bytes, to be filled +in by the application. 0 = do not insert, 1 = insert packets. + + + +
+
+
+ +
+ Camera Control Reference + + The Camera class includes controls for mechanical (or +equivalent digital) features of a device such as controllable lenses +or sensors. + + + Camera Control IDs + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_CAMERA_CLASS  + class + The Camera class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class. + + + + + V4L2_CID_EXPOSURE_AUTO  + enum v4l2_exposure_auto_type + Enables automatic +adjustments of the exposure time and/or iris aperture. The effect of +manual changes of the exposure time or iris aperture while these +features are enabled is undefined, drivers should ignore such +requests. Possible values are: + + + + + + V4L2_EXPOSURE_AUTO  + Automatic exposure time, automatic iris +aperture. + + + V4L2_EXPOSURE_MANUAL  + Manual exposure time, manual iris. + + + V4L2_EXPOSURE_SHUTTER_PRIORITY  + Manual exposure time, auto iris. + + + V4L2_EXPOSURE_APERTURE_PRIORITY  + Auto exposure time, manual iris. + + + + + + + + V4L2_CID_EXPOSURE_ABSOLUTE  + integer + Determines the exposure +time of the camera sensor. The exposure time is limited by the frame +interval. Drivers should interpret the values as 100 µs units, +where the value 1 stands for 1/10000th of a second, 10000 for 1 second +and 100000 for 10 seconds. + + + + + V4L2_CID_EXPOSURE_AUTO_PRIORITY  + boolean + When +V4L2_CID_EXPOSURE_AUTO is set to +AUTO or APERTURE_PRIORITY, +this control determines if the device may dynamically vary the frame +rate. By default this feature is disabled (0) and the frame rate must +remain constant. + + + + + V4L2_CID_PAN_RELATIVE  + integer + This control turns the +camera horizontally by the specified amount. The unit is undefined. A +positive value moves the camera to the right (clockwise when viewed +from above), a negative value to the left. A value of zero does not +cause motion. This is a write-only control. + + + + + V4L2_CID_TILT_RELATIVE  + integer + This control turns the +camera vertically by the specified amount. The unit is undefined. A +positive value moves the camera up, a negative value down. A value of +zero does not cause motion. This is a write-only control. + + + + + V4L2_CID_PAN_RESET  + button + When this control is set, +the camera moves horizontally to the default position. + + + + + V4L2_CID_TILT_RESET  + button + When this control is set, +the camera moves vertically to the default position. + + + + + V4L2_CID_PAN_ABSOLUTE  + integer + This control +turns the camera horizontally to the specified position. Positive +values move the camera to the right (clockwise when viewed from above), +negative values to the left. Drivers should interpret the values as arc +seconds, with valid values between -180 * 3600 and +180 * 3600 +inclusive. + + + + + V4L2_CID_TILT_ABSOLUTE  + integer + This control +turns the camera vertically to the specified position. Positive values +move the camera up, negative values down. Drivers should interpret the +values as arc seconds, with valid values between -180 * 3600 and +180 +* 3600 inclusive. + + + + + V4L2_CID_FOCUS_ABSOLUTE  + integer + This control sets the +focal point of the camera to the specified position. The unit is +undefined. Positive values set the focus closer to the camera, +negative values towards infinity. + + + + + V4L2_CID_FOCUS_RELATIVE  + integer + This control moves the +focal point of the camera by the specified amount. The unit is +undefined. Positive values move the focus closer to the camera, +negative values towards infinity. This is a write-only control. + + + + + V4L2_CID_FOCUS_AUTO  + boolean + Enables automatic focus +adjustments. The effect of manual focus adjustments while this feature +is enabled is undefined, drivers should ignore such requests. + + + + + V4L2_CID_ZOOM_ABSOLUTE  + integer + Specify the objective lens +focal length as an absolute value. The zoom unit is driver-specific and its +value should be a positive integer. + + + + + V4L2_CID_ZOOM_RELATIVE  + integer + Specify the objective lens +focal length relatively to the current value. Positive values move the zoom +lens group towards the telephoto direction, negative values towards the +wide-angle direction. The zoom unit is driver-specific. This is a write-only control. + + + + + V4L2_CID_ZOOM_CONTINUOUS  + integer + Move the objective lens group +at the specified speed until it reaches physical device limits or until an +explicit request to stop the movement. A positive value moves the zoom lens +group towards the telephoto direction. A value of zero stops the zoom lens +group movement. A negative value moves the zoom lens group towards the +wide-angle direction. The zoom speed unit is driver-specific. + + + + + V4L2_CID_IRIS_ABSOLUTE  + integer + This control sets the +camera's aperture to the specified value. The unit is undefined. +Larger values open the iris wider, smaller values close it. + + + + + V4L2_CID_IRIS_RELATIVE  + integer + This control modifies the +camera's aperture by the specified amount. The unit is undefined. +Positive values open the iris one step further, negative values close +it one step further. This is a write-only control. + + + + + V4L2_CID_PRIVACY  + boolean + Prevent video from being acquired +by the camera. When this control is set to TRUE (1), no +image can be captured by the camera. Common means to enforce privacy are +mechanical obturation of the sensor and firmware image processing, but the +device is not restricted to these methods. Devices that implement the privacy +control must support read access and may support write access. + + + + V4L2_CID_BAND_STOP_FILTER  + integer + Switch the band-stop filter of a +camera sensor on or off, or specify its strength. Such band-stop filters can +be used, for example, to filter out the fluorescent light component. + + + + +
+
+ +
+ FM Transmitter Control Reference + + The FM Transmitter (FM_TX) class includes controls for common features of +FM transmissions capable devices. Currently this class includes parameters for audio +compression, pilot tone generation, audio deviation limiter, RDS transmission and +tuning power features. + + + FM_TX Control IDs + + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_FM_TX_CLASS  + class + The FM_TX class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class. + + + V4L2_CID_RDS_TX_DEVIATION  + integer + + Configures RDS signal frequency deviation level in Hz. +The range and step are driver-specific. + + + V4L2_CID_RDS_TX_PI  + integer + + Sets the RDS Programme Identification field +for transmission. + + + V4L2_CID_RDS_TX_PTY  + integer + + Sets the RDS Programme Type field for transmission. +This encodes up to 31 pre-defined programme types. + + + V4L2_CID_RDS_TX_PS_NAME  + string + + Sets the Programme Service name (PS_NAME) for transmission. +It is intended for static display on a receiver. It is the primary aid to listeners in programme service +identification and selection. In Annex E of , the RDS specification, +there is a full description of the correct character encoding for Programme Service name strings. +Also from RDS specification, PS is usually a single eight character text. However, it is also possible +to find receivers which can scroll strings sized as 8 x N characters. So, this control must be configured +with steps of 8 characters. The result is it must always contain a string with size multiple of 8. + + + V4L2_CID_RDS_TX_RADIO_TEXT  + string + + Sets the Radio Text info for transmission. It is a textual description of +what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names, +programme-related information or any other text. In these cases, RadioText should be used in addition to +V4L2_CID_RDS_TX_PS_NAME. The encoding for Radio Text strings is also fully described +in Annex E of . The length of Radio Text strings depends on which RDS Block is being +used to transmit it, either 32 (2A block) or 64 (2B block). However, it is also possible +to find receivers which can scroll strings sized as 32 x N or 64 x N characters. So, this control must be configured +with steps of 32 or 64 characters. The result is it must always contain a string with size multiple of 32 or 64. + + + V4L2_CID_AUDIO_LIMITER_ENABLED  + boolean + + Enables or disables the audio deviation limiter feature. +The limiter is useful when trying to maximize the audio volume, minimize receiver-generated +distortion and prevent overmodulation. + + + + V4L2_CID_AUDIO_LIMITER_RELEASE_TIME  + integer + + Sets the audio deviation limiter feature release time. +Unit is in useconds. Step and range are driver-specific. + + + V4L2_CID_AUDIO_LIMITER_DEVIATION  + integer + + Configures audio frequency deviation level in Hz. +The range and step are driver-specific. + + + V4L2_CID_AUDIO_COMPRESSION_ENABLED  + boolean + + Enables or disables the audio compression feature. +This feature amplifies signals below the threshold by a fixed gain and compresses audio +signals above the threshold by the ratio of Threshold/(Gain + Threshold). + + + V4L2_CID_AUDIO_COMPRESSION_GAIN  + integer + + Sets the gain for audio compression feature. It is +a dB value. The range and step are driver-specific. + + + V4L2_CID_AUDIO_COMPRESSION_THRESHOLD  + integer + + Sets the threshold level for audio compression freature. +It is a dB value. The range and step are driver-specific. + + + V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME  + integer + + Sets the attack time for audio compression feature. +It is a useconds value. The range and step are driver-specific. + + + V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME  + integer + + Sets the release time for audio compression feature. +It is a useconds value. The range and step are driver-specific. + + + V4L2_CID_PILOT_TONE_ENABLED  + boolean + + Enables or disables the pilot tone generation feature. + + + V4L2_CID_PILOT_TONE_DEVIATION  + integer + + Configures pilot tone frequency deviation level. Unit is +in Hz. The range and step are driver-specific. + + + V4L2_CID_PILOT_TONE_FREQUENCY  + integer + + Configures pilot tone frequency value. Unit is +in Hz. The range and step are driver-specific. + + + V4L2_CID_TUNE_PREEMPHASIS  + integer + + Configures the pre-emphasis value for broadcasting. +A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies. +Depending on the region, a time constant of either 50 or 75 useconds is used. The enum v4l2_preemphasis +defines possible values for pre-emphasis. Here they are: + + + + + V4L2_PREEMPHASIS_DISABLED  + No pre-emphasis is applied. + + + V4L2_PREEMPHASIS_50_uS  + A pre-emphasis of 50 uS is used. + + + V4L2_PREEMPHASIS_75_uS  + A pre-emphasis of 75 uS is used. + + + + + + + V4L2_CID_TUNE_POWER_LEVEL  + integer + + Sets the output power level for signal transmission. +Unit is in dBuV. Range and step are driver-specific. + + + V4L2_CID_TUNE_ANTENNA_CAPACITOR  + integer + + This selects the value of antenna tuning capacitor +manually or automatically if set to zero. Unit, range and step are driver-specific. + + + + +
+ +For more details about RDS specification, refer to + document, from CENELEC. +
+
+ + diff --git a/Documentation/DocBook/media/v4l/crop.gif b/Documentation/DocBook/media/v4l/crop.gif new file mode 100644 index 00000000000..3b9e7d836d4 Binary files /dev/null and b/Documentation/DocBook/media/v4l/crop.gif differ diff --git a/Documentation/DocBook/media/v4l/crop.pdf b/Documentation/DocBook/media/v4l/crop.pdf new file mode 100644 index 00000000000..c9fb81cd32f Binary files /dev/null and b/Documentation/DocBook/media/v4l/crop.pdf differ diff --git a/Documentation/DocBook/media/v4l/dev-capture.xml b/Documentation/DocBook/media/v4l/dev-capture.xml new file mode 100644 index 00000000000..2237c661f26 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-capture.xml @@ -0,0 +1,118 @@ + Video Capture Interface + + Video capture devices sample an analog video signal and store +the digitized images in memory. Today nearly all devices can capture +at full 25 or 30 frames/second. With this interface applications can +control the capture process and move images from the driver into user +space. + + Conventionally V4L2 video capture devices are accessed through +character device special files named /dev/video +and /dev/video0 to +/dev/video63 with major number 81 and minor +numbers 0 to 63. /dev/video is typically a +symbolic link to the preferred video device. Note the same device +files are used for video output devices. + +
+ Querying Capabilities + + Devices supporting the video capture interface set the +V4L2_CAP_VIDEO_CAPTURE or +V4L2_CAP_VIDEO_CAPTURE_MPLANE flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the video overlay +(V4L2_CAP_VIDEO_OVERLAY) and the raw VBI capture +(V4L2_CAP_VBI_CAPTURE) interface. At least one of +the read/write or streaming I/O methods must be supported. Tuners and +audio inputs are optional. +
+ +
+ Supplemental Functions + + Video capture devices shall support audio input, tuner, controls, +cropping and scaling and streaming parameter ioctls as needed. +The video input and video standard ioctls must be supported by +all video capture devices. +
+ +
+ Image Format Negotiation + + The result of a capture operation is determined by +cropping and image format parameters. The former select an area of the +video picture to capture, the latter how images are stored in memory, +&ie; in RGB or YUV format, the number of bits per pixel or width and +height. Together they also define how images are scaled in the +process. + + As usual these parameters are not reset +at &func-open; time to permit Unix tool chains, programming a device +and then reading from it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling. + + Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in . + + To query the current image format applications set the +type field of a &v4l2-format; to +V4L2_BUF_TYPE_VIDEO_CAPTURE or +V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; pix or the +&v4l2-pix-format-mplane; pix_mp member of the +fmt union. + + To request different parameters applications set the +type field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +vbi member of the +fmt union, or better just modify the +results of VIDIOC_G_FMT, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +VIDIOC_G_FMT does. + + Like VIDIOC_S_FMT the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations. + + The contents of &v4l2-pix-format; and &v4l2-pix-format-mplane; +are discussed in . See also the specification of the +VIDIOC_G_FMT, VIDIOC_S_FMT +and VIDIOC_TRY_FMT ioctls for details. Video +capture devices must implement both the +VIDIOC_G_FMT and +VIDIOC_S_FMT ioctl, even if +VIDIOC_S_FMT ignores all requests and always +returns default parameters as VIDIOC_G_FMT does. +VIDIOC_TRY_FMT is optional. +
+ +
+ Reading Images + + A video capture device may support the read() function and/or streaming (memory mapping or user pointer) I/O. See for details. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-codec.xml b/Documentation/DocBook/media/v4l/dev-codec.xml new file mode 100644 index 00000000000..6e156dc45b9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-codec.xml @@ -0,0 +1,26 @@ + Codec Interface + + + Suspended + + This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with codec +device interfaces. + + + A V4L2 codec can compress, decompress, transform, or otherwise +convert video data from one format into another format, in memory. +Applications send data to be converted to the driver through a +&func-write; call, and receive the converted data through a +&func-read; call. For efficiency a driver may also support streaming +I/O. + + [to do] + + diff --git a/Documentation/DocBook/media/v4l/dev-effect.xml b/Documentation/DocBook/media/v4l/dev-effect.xml new file mode 100644 index 00000000000..9c243beba0e --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-effect.xml @@ -0,0 +1,25 @@ + Effect Devices Interface + + + Suspended + + This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with effect +device interfaces. + + + A V4L2 video effect device can do image effects, filtering, or +combine two or more images or image streams. For example video +transitions or wipes. Applications send data to be processed and +receive the result data either with &func-read; and &func-write; +functions, or through the streaming I/O mechanism. + + [to do] + + diff --git a/Documentation/DocBook/media/v4l/dev-event.xml b/Documentation/DocBook/media/v4l/dev-event.xml new file mode 100644 index 00000000000..be5a98fb4fa --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-event.xml @@ -0,0 +1,31 @@ + Event Interface + + The V4L2 event interface provides means for user to get + immediately notified on certain conditions taking place on a device. + This might include start of frame or loss of signal events, for + example. + + + To receive events, the events the user is interested in first must + be subscribed using the &VIDIOC-SUBSCRIBE-EVENT; ioctl. Once an event is + subscribed, the events of subscribed types are dequeueable using the + &VIDIOC-DQEVENT; ioctl. Events may be unsubscribed using + VIDIOC_UNSUBSCRIBE_EVENT ioctl. The special event type V4L2_EVENT_ALL may + be used to unsubscribe all the events the driver supports. + + The event subscriptions and event queues are specific to file + handles. Subscribing an event on one file handle does not affect + other file handles. + + + The information on dequeueable events is obtained by using select or + poll system calls on video devices. The V4L2 events use POLLPRI events on + poll system call and exceptions on select system call. + + diff --git a/Documentation/DocBook/media/v4l/dev-osd.xml b/Documentation/DocBook/media/v4l/dev-osd.xml new file mode 100644 index 00000000000..c9a68a2ccd3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-osd.xml @@ -0,0 +1,164 @@ + Video Output Overlay Interface + Also known as On-Screen Display (OSD) + + + Experimental + + This is an experimental +interface and may change in the future. + + + Some video output devices can overlay a framebuffer image onto +the outgoing video signal. Applications can set up such an overlay +using this interface, which borrows structures and ioctls of the Video Overlay interface. + + The OSD function is accessible through the same character +special file as the Video Output function. +Note the default function of such a /dev/video device +is video capturing or output. The OSD function is only available after +calling the &VIDIOC-S-FMT; ioctl. + +
+ Querying Capabilities + + Devices supporting the Video Output +Overlay interface set the +V4L2_CAP_VIDEO_OUTPUT_OVERLAY flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. +
+ +
+ Framebuffer + + Contrary to the Video Overlay +interface the framebuffer is normally implemented on the TV card and +not the graphics card. On Linux it is accessible as a framebuffer +device (/dev/fbN). Given a V4L2 device, +applications can find the corresponding framebuffer device by calling +the &VIDIOC-G-FBUF; ioctl. It returns, amongst other information, the +physical address of the framebuffer in the +base field of &v4l2-framebuffer;. The +framebuffer device ioctl FBIOGET_FSCREENINFO +returns the same address in the smem_start +field of struct fb_fix_screeninfo. The +FBIOGET_FSCREENINFO ioctl and struct +fb_fix_screeninfo are defined in the +linux/fb.h header file. + + The width and height of the framebuffer depends on the +current video standard. A V4L2 driver may reject attempts to change +the video standard (or any other ioctl which would imply a framebuffer +size change) with an &EBUSY; until all applications closed the +framebuffer device. + + + Finding a framebuffer device for OSD + + +#include <linux/fb.h> + +&v4l2-framebuffer; fbuf; +unsigned int i; +int fb_fd; + +if (-1 == ioctl (fd, VIDIOC_G_FBUF, &fbuf)) { + perror ("VIDIOC_G_FBUF"); + exit (EXIT_FAILURE); +} + +for (i = 0; i > 30; ++i) { + char dev_name[16]; + struct fb_fix_screeninfo si; + + snprintf (dev_name, sizeof (dev_name), "/dev/fb%u", i); + + fb_fd = open (dev_name, O_RDWR); + if (-1 == fb_fd) { + switch (errno) { + case ENOENT: /* no such file */ + case ENXIO: /* no driver */ + continue; + + default: + perror ("open"); + exit (EXIT_FAILURE); + } + } + + if (0 == ioctl (fb_fd, FBIOGET_FSCREENINFO, &si)) { + if (si.smem_start == (unsigned long) fbuf.base) + break; + } else { + /* Apparently not a framebuffer device. */ + } + + close (fb_fd); + fb_fd = -1; +} + +/* fb_fd is the file descriptor of the framebuffer device + for the video output overlay, or -1 if no device was found. */ + + +
+ +
+ Overlay Window and Scaling + + The overlay is controlled by source and target rectangles. +The source rectangle selects a subsection of the framebuffer image to +be overlaid, the target rectangle an area in the outgoing video signal +where the image will appear. Drivers may or may not support scaling, +and arbitrary sizes and positions of these rectangles. Further drivers +may support any (or none) of the clipping/blending methods defined for +the Video Overlay interface. + + A &v4l2-window; defines the size of the source rectangle, +its position in the framebuffer and the clipping/blending method to be +used for the overlay. To get the current parameters applications set +the type field of a &v4l2-format; to +V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY and call the +&VIDIOC-G-FMT; ioctl. The driver fills the +v4l2_window substructure named +win. It is not possible to retrieve a +previously programmed clipping list or bitmap. + + To program the source rectangle applications set the +type field of a &v4l2-format; to +V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY, initialize +the win substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +VIDIOC_G_FMT does. Like +VIDIOC_S_FMT, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike VIDIOC_S_FMT this also works +after the overlay has been enabled. + + A &v4l2-crop; defines the size and position of the target +rectangle. The scaling factor of the overlay is implied by the width +and height given in &v4l2-window; and &v4l2-crop;. The cropping API +applies to Video Output and Video +Output Overlay devices in the same way as to +Video Capture and Video +Overlay devices, merely reversing the direction of the +data flow. For more information see . +
+ +
+ Enabling Overlay + + There is no V4L2 ioctl to enable or disable the overlay, +however the framebuffer interface of the driver may support the +FBIOBLANK ioctl. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-output.xml b/Documentation/DocBook/media/v4l/dev-output.xml new file mode 100644 index 00000000000..919e22c5385 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-output.xml @@ -0,0 +1,114 @@ + Video Output Interface + + Video output devices encode stills or image sequences as +analog video signal. With this interface applications can +control the encoding process and move images from user space to +the driver. + + Conventionally V4L2 video output devices are accessed through +character device special files named /dev/video +and /dev/video0 to +/dev/video63 with major number 81 and minor +numbers 0 to 63. /dev/video is typically a +symbolic link to the preferred video device. Note the same device +files are used for video capture devices. + +
+ Querying Capabilities + + Devices supporting the video output interface set the +V4L2_CAP_VIDEO_OUTPUT or +V4L2_CAP_VIDEO_OUTPUT_MPLANE flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the raw VBI +output (V4L2_CAP_VBI_OUTPUT) interface. At +least one of the read/write or streaming I/O methods must be +supported. Modulators and audio outputs are optional. +
+ +
+ Supplemental Functions + + Video output devices shall support audio output, modulator, controls, +cropping and scaling and streaming parameter ioctls as needed. +The video output and video standard ioctls must be supported by +all video output devices. +
+ +
+ Image Format Negotiation + + The output is determined by cropping and image format +parameters. The former select an area of the video picture where the +image will appear, the latter how images are stored in memory, &ie; in +RGB or YUV format, the number of bits per pixel or width and height. +Together they also define how images are scaled in the process. + + As usual these parameters are not reset +at &func-open; time to permit Unix tool chains, programming a device +and then writing to it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling. + + Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in . + + To query the current image format applications set the +type field of a &v4l2-format; to +V4L2_BUF_TYPE_VIDEO_OUTPUT or +V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; pix or the +&v4l2-pix-format-mplane; pix_mp member of the +fmt union. + + To request different parameters applications set the +type field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +vbi member of the +fmt union, or better just modify the +results of VIDIOC_G_FMT, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +VIDIOC_G_FMT does. + + Like VIDIOC_S_FMT the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations. + + The contents of &v4l2-pix-format; and &v4l2-pix-format-mplane; +are discussed in . See also the specification of the +VIDIOC_G_FMT, VIDIOC_S_FMT +and VIDIOC_TRY_FMT ioctls for details. Video +output devices must implement both the +VIDIOC_G_FMT and +VIDIOC_S_FMT ioctl, even if +VIDIOC_S_FMT ignores all requests and always +returns default parameters as VIDIOC_G_FMT does. +VIDIOC_TRY_FMT is optional. +
+ +
+ Writing Images + + A video output device may support the write() function and/or streaming (memory mapping or user pointer) I/O. See for details. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-overlay.xml b/Documentation/DocBook/media/v4l/dev-overlay.xml new file mode 100644 index 00000000000..92513cf7915 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-overlay.xml @@ -0,0 +1,379 @@ + Video Overlay Interface + Also known as Framebuffer Overlay or Previewing + + Video overlay devices have the ability to genlock (TV-)video +into the (VGA-)video signal of a graphics card, or to store captured +images directly in video memory of a graphics card, typically with +clipping. This can be considerable more efficient than capturing +images and displaying them by other means. In the old days when only +nuclear power plants needed cooling towers this used to be the only +way to put live video into a window. + + Video overlay devices are accessed through the same character +special files as video capture devices. +Note the default function of a /dev/video device +is video capturing. The overlay function is only available after +calling the &VIDIOC-S-FMT; ioctl. + + The driver may support simultaneous overlay and capturing +using the read/write and streaming I/O methods. If so, operation at +the nominal frame rate of the video standard is not guaranteed. Frames +may be directed away from overlay to capture, or one field may be used +for overlay and the other for capture if the capture parameters permit +this. + + Applications should use different file descriptors for +capturing and overlay. This must be supported by all drivers capable +of simultaneous capturing and overlay. Optionally these drivers may +also permit capturing and overlay with a single file descriptor for +compatibility with V4L and earlier versions of V4L2. + A common application of two file descriptors is the +XFree86 Xv/V4L interface driver and +a V4L2 application. While the X server controls video overlay, the +application can take advantage of memory mapping and DMA. + In the opinion of the designers of this API, no driver +writer taking the efforts to support simultaneous capturing and +overlay will restrict this ability by requiring a single file +descriptor, as in V4L and earlier versions of V4L2. Making this +optional means applications depending on two file descriptors need +backup routines to be compatible with all drivers, which is +considerable more work than using two fds in applications which do +not. Also two fd's fit the general concept of one file descriptor for +each logical stream. Hence as a complexity trade-off drivers +must support two file descriptors and +may support single fd operation. + + +
+ Querying Capabilities + + Devices supporting the video overlay interface set the +V4L2_CAP_VIDEO_OVERLAY flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. The overlay I/O method specified +below must be supported. Tuners and audio inputs are optional. +
+ +
+ Supplemental Functions + + Video overlay devices shall support audio input, tuner, controls, +cropping and scaling and streaming parameter ioctls as needed. +The video input and video standard ioctls must be supported by +all video overlay devices. +
+ +
+ Setup + + Before overlay can commence applications must program the +driver with frame buffer parameters, namely the address and size of +the frame buffer and the image format, for example RGB 5:6:5. The +&VIDIOC-G-FBUF; and &VIDIOC-S-FBUF; ioctls are available to get +and set these parameters, respectively. The +VIDIOC_S_FBUF ioctl is privileged because it +allows to set up DMA into physical memory, bypassing the memory +protection mechanisms of the kernel. Only the superuser can change the +frame buffer address and size. Users are not supposed to run TV +applications as root or with SUID bit set. A small helper application +with suitable privileges should query the graphics system and program +the V4L2 driver at the appropriate time. + + Some devices add the video overlay to the output signal +of the graphics card. In this case the frame buffer is not modified by +the video device, and the frame buffer address and pixel format are +not needed by the driver. The VIDIOC_S_FBUF ioctl +is not privileged. An application can check for this type of device by +calling the VIDIOC_G_FBUF ioctl. + + A driver may support any (or none) of five clipping/blending +methods: + + Chroma-keying displays the overlaid image only where +pixels in the primary graphics surface assume a certain color. + + + A bitmap can be specified where each bit corresponds +to a pixel in the overlaid image. When the bit is set, the +corresponding video pixel is displayed, otherwise a pixel of the +graphics surface. + + + A list of clipping rectangles can be specified. In +these regions no video is displayed, so the +graphics surface can be seen here. + + + The framebuffer has an alpha channel that can be used +to clip or blend the framebuffer with the video. + + + A global alpha value can be specified to blend the +framebuffer contents with video images. + + + + When simultaneous capturing and overlay is supported and +the hardware prohibits different image and frame buffer formats, the +format requested first takes precedence. The attempt to capture +(&VIDIOC-S-FMT;) or overlay (&VIDIOC-S-FBUF;) may fail with an +&EBUSY; or return accordingly modified parameters.. +
+ +
+ Overlay Window + + The overlaid image is determined by cropping and overlay +window parameters. The former select an area of the video picture to +capture, the latter how images are overlaid and clipped. Cropping +initialization at minimum requires to reset the parameters to +defaults. An example is given in . + + The overlay window is described by a &v4l2-window;. It +defines the size of the image, its position over the graphics surface +and the clipping to be applied. To get the current parameters +applications set the type field of a +&v4l2-format; to V4L2_BUF_TYPE_VIDEO_OVERLAY and +call the &VIDIOC-G-FMT; ioctl. The driver fills the +v4l2_window substructure named +win. It is not possible to retrieve a +previously programmed clipping list or bitmap. + + To program the overlay window applications set the +type field of a &v4l2-format; to +V4L2_BUF_TYPE_VIDEO_OVERLAY, initialize the +win substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +VIDIOC_G_FMT does. Like +VIDIOC_S_FMT, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike VIDIOC_S_FMT this also works +after the overlay has been enabled. + + The scaling factor of the overlaid image is implied by the +width and height given in &v4l2-window; and the size of the cropping +rectangle. For more information see . + + When simultaneous capturing and overlay is supported and +the hardware prohibits different image and window sizes, the size +requested first takes precedence. The attempt to capture or overlay as +well (&VIDIOC-S-FMT;) may fail with an &EBUSY; or return accordingly +modified parameters. + + + struct <structname>v4l2_window</structname> + + &cs-str; + + + &v4l2-rect; + w + Size and position of the window relative to the +top, left corner of the frame buffer defined with &VIDIOC-S-FBUF;. The +window can extend the frame buffer width and height, the +x and y +coordinates can be negative, and it can lie completely outside the +frame buffer. The driver clips the window accordingly, or if that is +not possible, modifies its size and/or position. + + + &v4l2-field; + field + Applications set this field to determine which +video field shall be overlaid, typically one of +V4L2_FIELD_ANY (0), +V4L2_FIELD_TOP, +V4L2_FIELD_BOTTOM or +V4L2_FIELD_INTERLACED. Drivers may have to choose +a different field order and return the actual setting here. + + + __u32 + chromakey + When chroma-keying has been negotiated with +&VIDIOC-S-FBUF; applications set this field to the desired pixel value +for the chroma key. The format is the same as the pixel format of the +framebuffer (&v4l2-framebuffer; +fmt.pixelformat field), with bytes in host +order. E. g. for V4L2_PIX_FMT_BGR24 +the value should be 0xRRGGBB on a little endian, 0xBBGGRR on a big +endian host. + + + &v4l2-clip; * + clips + When chroma-keying has not +been negotiated and &VIDIOC-G-FBUF; indicated this capability, +applications can set this field to point to an array of +clipping rectangles. + + + + + Like the window coordinates +w, clipping rectangles are defined relative +to the top, left corner of the frame buffer. However clipping +rectangles must not extend the frame buffer width and height, and they +must not overlap. If possible applications should merge adjacent +rectangles. Whether this must create x-y or y-x bands, or the order of +rectangles, is not defined. When clip lists are not supported the +driver ignores this field. Its contents after calling &VIDIOC-S-FMT; +are undefined. + + + __u32 + clipcount + When the application set the +clips field, this field must contain the +number of clipping rectangles in the list. When clip lists are not +supported the driver ignores this field, its contents after calling +VIDIOC_S_FMT are undefined. When clip lists are +supported but no clipping is desired this field must be set to +zero. + + + void * + bitmap + When chroma-keying has +not been negotiated and &VIDIOC-G-FBUF; indicated +this capability, applications can set this field to point to a +clipping bit mask. + + + It must be of the same size +as the window, w.width and +w.height. Each bit corresponds to a pixel +in the overlaid image, which is displayed only when the bit is +set. Pixel coordinates translate to bits like: + +((__u8 *) bitmap)[w.width * y + x / 8] & (1 << (x & 7))where 0 ≤ x < +w.width and 0 ≤ +y <w.height. + Should we require + w.width to be a multiple of + eight? + When a clipping +bit mask is not supported the driver ignores this field, its contents +after calling &VIDIOC-S-FMT; are undefined. When a bit mask is supported +but no clipping is desired this field must be set to +NULL.Applications need not create a +clip list or bit mask. When they pass both, or despite negotiating +chroma-keying, the results are undefined. Regardless of the chosen +method, the clipping abilities of the hardware may be limited in +quantity or quality. The results when these limits are exceeded are +undefined. + When the image is written into frame buffer +memory it will be undesirable if the driver clips out less pixels +than expected, because the application and graphics system are not +aware these regions need to be refreshed. The driver should clip out +more pixels or not write the image at all. + + + + __u8 + global_alpha + The global alpha value used to blend the +framebuffer with video images, if global alpha blending has been +negotiated (V4L2_FBUF_FLAG_GLOBAL_ALPHA, see +&VIDIOC-S-FBUF;, ). + + + + + Note this field was added in Linux 2.6.23, extending the structure. However +the VIDIOC_G/S/TRY_FMT ioctls, +which take a pointer to a v4l2_format parent structure with padding +bytes at the end, are not affected. + + + +
+ + + struct <structname>v4l2_clip</structname><footnote> + <para>The X Window system defines "regions" which are +vectors of struct BoxRec { short x1, y1, x2, y2; } with width = x2 - +x1 and height = y2 - y1, so one cannot pass X11 clip lists +directly.</para> + </footnote> + + &cs-str; + + + &v4l2-rect; + c + Coordinates of the clipping rectangle, relative to +the top, left corner of the frame buffer. Only window pixels +outside all clipping rectangles are +displayed. + + + &v4l2-clip; * + next + Pointer to the next clipping rectangle, NULL when +this is the last rectangle. Drivers ignore this field, it cannot be +used to pass a linked list of clipping rectangles. + + + +
+ + + + + struct <structname>v4l2_rect</structname> + + &cs-str; + + + __s32 + left + Horizontal offset of the top, left corner of the +rectangle, in pixels. + + + __s32 + top + Vertical offset of the top, left corner of the +rectangle, in pixels. Offsets increase to the right and down. + + + __s32 + width + Width of the rectangle, in pixels. + + + __s32 + height + Height of the rectangle, in pixels. Width and +height cannot be negative, the fields are signed for hysterical +reasons. + + + +
+
+ +
+ Enabling Overlay + + To start or stop the frame buffer overlay applications call +the &VIDIOC-OVERLAY; ioctl. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-radio.xml b/Documentation/DocBook/media/v4l/dev-radio.xml new file mode 100644 index 00000000000..73aa90b45b3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-radio.xml @@ -0,0 +1,57 @@ + Radio Interface + + This interface is intended for AM and FM (analog) radio +receivers and transmitters. + + Conventionally V4L2 radio devices are accessed through +character device special files named /dev/radio +and /dev/radio0 to +/dev/radio63 with major number 81 and minor +numbers 64 to 127. + +
+ Querying Capabilities + + Devices supporting the radio interface set the +V4L2_CAP_RADIO and +V4L2_CAP_TUNER or +V4L2_CAP_MODULATOR flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. Other combinations of +capability flags are reserved for future extensions. +
+ +
+ Supplemental Functions + + Radio devices can support controls, and must support the tuner or modulator ioctls. + + They do not support the video input or output, audio input +or output, video standard, cropping and scaling, compression and +streaming parameter, or overlay ioctls. All other ioctls and I/O +methods are reserved for future extensions. +
+ +
+ Programming + + Radio devices may have a couple audio controls (as discussed +in ) such as a volume control, possibly custom +controls. Further all radio devices have one tuner or modulator (these are +discussed in ) with index number zero to select +the radio frequency and to determine if a monaural or FM stereo +program is received/emitted. Drivers switch automatically between AM and FM +depending on the selected frequency. The &VIDIOC-G-TUNER; or +&VIDIOC-G-MODULATOR; ioctl +reports the supported frequency range. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-raw-vbi.xml b/Documentation/DocBook/media/v4l/dev-raw-vbi.xml new file mode 100644 index 00000000000..c5a70bdfaf2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-raw-vbi.xml @@ -0,0 +1,347 @@ + Raw VBI Data Interface + + VBI is an abbreviation of Vertical Blanking Interval, a gap +in the sequence of lines of an analog video signal. During VBI +no picture information is transmitted, allowing some time while the +electron beam of a cathode ray tube TV returns to the top of the +screen. Using an oscilloscope you will find here the vertical +synchronization pulses and short data packages ASK +modulatedASK: Amplitude-Shift Keying. A high signal +level represents a '1' bit, a low level a '0' bit. +onto the video signal. These are transmissions of services such as +Teletext or Closed Caption. + + Subject of this interface type is raw VBI data, as sampled off +a video signal, or to be added to a signal for output. +The data format is similar to uncompressed video images, a number of +lines times a number of samples per line, we call this a VBI image. + + Conventionally V4L2 VBI devices are accessed through character +device special files named /dev/vbi and +/dev/vbi0 to /dev/vbi31 with +major number 81 and minor numbers 224 to 255. +/dev/vbi is typically a symbolic link to the +preferred VBI device. This convention applies to both input and output +devices. + + To address the problems of finding related video and VBI +devices VBI capturing and output is also available as device function +under /dev/video. To capture or output raw VBI +data with these devices applications must call the &VIDIOC-S-FMT; +ioctl. Accessed as /dev/vbi, raw VBI capturing +or output is the default device function. + +
+ Querying Capabilities + + Devices supporting the raw VBI capturing or output API set +the V4L2_CAP_VBI_CAPTURE or +V4L2_CAP_VBI_OUTPUT flags, respectively, in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous I/O methods must be +supported. VBI devices may or may not have a tuner or modulator. +
+ +
+ Supplemental Functions + + VBI devices shall support video +input or output, tuner or +modulator, and controls ioctls +as needed. The video standard ioctls provide +information vital to program a VBI device, therefore must be +supported. +
+ +
+ Raw VBI Format Negotiation + + Raw VBI sampling abilities can vary, in particular the +sampling frequency. To properly interpret the data V4L2 specifies an +ioctl to query the sampling parameters. Moreover, to allow for some +flexibility applications can also suggest different parameters. + + As usual these parameters are not +reset at &func-open; time to permit Unix tool chains, programming a +device and then reading from it as if it was a plain file. Well +written V4L2 applications should always ensure they really get what +they want, requesting reasonable parameters and then checking if the +actual parameters are suitable. + + To query the current raw VBI capture parameters +applications set the type field of a +&v4l2-format; to V4L2_BUF_TYPE_VBI_CAPTURE or +V4L2_BUF_TYPE_VBI_OUTPUT, and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-vbi-format; vbi member of the +fmt union. + + To request different parameters applications set the +type field of a &v4l2-format; as above and +initialize all fields of the &v4l2-vbi-format; +vbi member of the +fmt union, or better just modify the +results of VIDIOC_G_FMT, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers return +an &EINVAL; only when the given parameters are ambiguous, otherwise +they modify the parameters according to the hardware capabilites and +return the actual parameters. When the driver allocates resources at +this point, it may return an &EBUSY; to indicate the returned +parameters are valid but the required resources are currently not +available. That may happen for instance when the video and VBI areas +to capture would overlap, or when the driver supports multiple opens +and another process already requested VBI capturing or output. Anyway, +applications must expect other resource allocation points which may +return EBUSY, at the &VIDIOC-STREAMON; ioctl +and the first read(), write() and select() call. + + VBI devices must implement both the +VIDIOC_G_FMT and +VIDIOC_S_FMT ioctl, even if +VIDIOC_S_FMT ignores all requests and always +returns default parameters as VIDIOC_G_FMT does. +VIDIOC_TRY_FMT is optional. + + + struct <structname>v4l2_vbi_format</structname> + + &cs-str; + + + __u32 + sampling_rate + Samples per second, i. e. unit 1 Hz. + + + __u32 + offset + Horizontal offset of the VBI image, +relative to the leading edge of the line synchronization pulse and +counted in samples: The first sample in the VBI image will be located +offset / +sampling_rate seconds following the leading +edge. See also . + + + __u32 + samples_per_line + + + + __u32 + sample_format + Defines the sample format as in , a four-character-code. + A few devices may be unable to +sample VBI data at all but can extend the video capture window to the +VBI region. + Usually this is +V4L2_PIX_FMT_GREY, i. e. each sample +consists of 8 bits with lower values oriented towards the black level. +Do not assume any other correlation of values with the signal level. +For example, the MSB does not necessarily indicate if the signal is +'high' or 'low' because 128 may not be the mean value of the +signal. Drivers shall not convert the sample format by software. + + + __u32 + start[2] + This is the scanning system line number +associated with the first line of the VBI image, of the first and the +second field respectively. See and + for valid values. VBI input drivers can +return start values 0 if the hardware cannot reliable identify +scanning lines, VBI acquisition may not require this +information. + + + __u32 + count[2] + The number of lines in the first and second +field image, respectively. + + + Drivers should be as +flexibility as possible. For example, it may be possible to extend or +move the VBI capture window down to the picture area, implementing a +'full field mode' to capture data service transmissions embedded in +the picture.An application can set the first or second +count value to zero if no data is required +from the respective field; count[1] if the +scanning system is progressive, &ie; not interlaced. The +corresponding start value shall be ignored by the application and +driver. Anyway, drivers may not support single field capturing and +return both count values non-zero.Both +count values set to zero, or line numbers +outside the bounds depicted in and , or a field image covering +lines of two fields, are invalid and shall not be returned by the +driver.To initialize the start +and count fields, applications must first +determine the current video standard selection. The &v4l2-std-id; or +the framelines field of &v4l2-standard; can +be evaluated for this purpose. + + + __u32 + flags + See below. Currently +only drivers set flags, applications must set this field to +zero. + + + __u32 + reserved[2] + This array is reserved for future extensions. +Drivers and applications must set it to zero. + + + +
+ + + Raw VBI Format Flags + + &cs-def; + + + V4L2_VBI_UNSYNC + 0x0001 + This flag indicates hardware which does not +properly distinguish between fields. Normally the VBI image stores the +first field (lower scanning line numbers) first in memory. This may be +a top or bottom field depending on the video standard. When this flag +is set the first or second field may be stored first, however the +fields are still in correct temporal order with the older field first +in memory. + Most VBI services transmit on both fields, but +some have different semantics depending on the field number. These +cannot be reliable decoded or encoded when +V4L2_VBI_UNSYNC is set. + + + + V4L2_VBI_INTERLACED + 0x0002 + By default the two field images will be passed +sequentially; all lines of the first field followed by all lines of +the second field (compare +V4L2_FIELD_SEQ_TB and +V4L2_FIELD_SEQ_BT, whether the top or bottom +field is first in memory depends on the video standard). When this +flag is set, the two fields are interlaced (cf. +V4L2_FIELD_INTERLACED). The first line of the +first field followed by the first line of the second field, then the +two second lines, and so on. Such a layout may be necessary when the +hardware has been programmed to capture or output interlaced video +images and is unable to separate the fields for VBI capturing at +the same time. For simplicity setting this flag implies that both +count values are equal and non-zero. + + + +
+ +
+ Line synchronization + + + + + + + + + Line synchronization diagram + + +
+ +
+ ITU-R 525 line numbering (M/NTSC and M/PAL) + + + + + + + + + NTSC field synchronization diagram + + + (1) For the purpose of this specification field 2 +starts in line 264 and not 263.5 because half line capturing is not +supported. + + +
+ +
+ ITU-R 625 line numbering + + + + + + + + + PAL/SECAM field synchronization diagram + + + (1) For the purpose of this specification field 2 +starts in line 314 and not 313.5 because half line capturing is not +supported. + + +
+ + Remember the VBI image format depends on the selected +video standard, therefore the application must choose a new standard or +query the current standard first. Attempts to read or write data ahead +of format negotiation, or after switching the video standard which may +invalidate the negotiated VBI parameters, should be refused by the +driver. A format change during active I/O is not permitted. +
+ +
+ Reading and writing VBI images + + To assure synchronization with the field number and easier +implementation, the smallest unit of data passed at a time is one +frame, consisting of two fields of VBI images immediately following in +memory. + + The total size of a frame computes as follows: + + +(count[0] + count[1]) * +samples_per_line * sample size in bytes + + The sample size is most likely always one byte, +applications must check the sample_format +field though, to function properly with other drivers. + + A VBI device may support read/write and/or streaming (memory mapping or user pointer) I/O. The latter bears the +possibility of synchronizing video and +VBI data by using buffer timestamps. + + Remember the &VIDIOC-STREAMON; ioctl and the first read(), +write() and select() call can be resource allocation points returning +an &EBUSY; if the required hardware resources are temporarily +unavailable, for example the device is already in use by another +process. +
+ + diff --git a/Documentation/DocBook/media/v4l/dev-rds.xml b/Documentation/DocBook/media/v4l/dev-rds.xml new file mode 100644 index 00000000000..2427f54397e --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-rds.xml @@ -0,0 +1,204 @@ + RDS Interface + + The Radio Data System transmits supplementary +information in binary format, for example the station name or travel +information, on an inaudible audio subcarrier of a radio program. This +interface is aimed at devices capable of receiving and/or transmitting RDS +information. + + For more information see the core RDS standard +and the RBDS standard . + + Note that the RBDS standard as is used in the USA is almost identical +to the RDS standard. Any RDS decoder/encoder can also handle RBDS. Only some of the +fields have slightly different meanings. See the RBDS standard for more +information. + + The RBDS standard also specifies support for MMBS (Modified Mobile Search). +This is a proprietary format which seems to be discontinued. The RDS interface does not +support this format. Should support for MMBS (or the so-called 'E blocks' in general) +be needed, then please contact the linux-media mailing list: &v4l-ml;. + +
+ Querying Capabilities + + Devices supporting the RDS capturing API set +the V4L2_CAP_RDS_CAPTURE flag in +the capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. Any tuner that supports RDS +will set the V4L2_TUNER_CAP_RDS flag in +the capability field of &v4l2-tuner;. If +the driver only passes RDS blocks without interpreting the data +the V4L2_TUNER_SUB_RDS_BLOCK_IO flag has to be +set, see Reading RDS data. +For future use the +flag V4L2_TUNER_SUB_RDS_CONTROLS has also been +defined. However, a driver for a radio tuner with this capability does +not yet exist, so if you are planning to write such a driver you +should discuss this on the linux-media mailing list: &v4l-ml;. + + Whether an RDS signal is present can be detected by looking +at the rxsubchans field of &v4l2-tuner;: +the V4L2_TUNER_SUB_RDS will be set if RDS data +was detected. + + Devices supporting the RDS output API +set the V4L2_CAP_RDS_OUTPUT flag in +the capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. +Any modulator that supports RDS will set the +V4L2_TUNER_CAP_RDS flag in the capability +field of &v4l2-modulator;. +In order to enable the RDS transmission one must set the V4L2_TUNER_SUB_RDS +bit in the txsubchans field of &v4l2-modulator;. +If the driver only passes RDS blocks without interpreting the data +the V4L2_TUNER_SUB_RDS_BLOCK_IO flag has to be set. If the +tuner is capable of handling RDS entities like program identification codes and radio +text, the flag V4L2_TUNER_SUB_RDS_CONTROLS should be set, +see Writing RDS data and +FM Transmitter Control Reference. +
+ +
+ Reading RDS data + + RDS data can be read from the radio device +with the &func-read; function. The data is packed in groups of three bytes. +
+ +
+ Writing RDS data + + RDS data can be written to the radio device +with the &func-write; function. The data is packed in groups of three bytes, +as follows: +
+ +
+ RDS datastructures + + struct +<structname>v4l2_rds_data</structname> + + + + + + + __u8 + lsb + Least Significant Byte of RDS Block + + + __u8 + msb + Most Significant Byte of RDS Block + + + __u8 + block + Block description + + + +
+ + Block description + + + + + + Bits 0-2 + Block (aka offset) of the received data. + + + Bits 3-5 + Deprecated. Currently identical to bits 0-2. Do not use these bits. + + + Bit 6 + Corrected bit. Indicates that an error was corrected for this data block. + + + Bit 7 + Error bit. Indicates that an uncorrectable error occurred during reception of this block. + + + +
+ + + Block defines + + + + + + + + V4L2_RDS_BLOCK_MSK + + 7 + Mask for bits 0-2 to get the block ID. + + + V4L2_RDS_BLOCK_A + + 0 + Block A. + + + V4L2_RDS_BLOCK_B + + 1 + Block B. + + + V4L2_RDS_BLOCK_C + + 2 + Block C. + + + V4L2_RDS_BLOCK_D + + 3 + Block D. + + + V4L2_RDS_BLOCK_C_ALT + + 4 + Block C'. + + + V4L2_RDS_BLOCK_INVALID + read-only + 7 + An invalid block. + + + V4L2_RDS_BLOCK_CORRECTED + read-only + 0x40 + A bit error was detected but corrected. + + + V4L2_RDS_BLOCK_ERROR + read-only + 0x80 + An uncorrectable error occurred. + + + +
+
+ + diff --git a/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml new file mode 100644 index 00000000000..69e789fa7f7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-sliced-vbi.xml @@ -0,0 +1,708 @@ + Sliced VBI Data Interface + + VBI stands for Vertical Blanking Interval, a gap in the +sequence of lines of an analog video signal. During VBI no picture +information is transmitted, allowing some time while the electron beam +of a cathode ray tube TV returns to the top of the screen. + + Sliced VBI devices use hardware to demodulate data transmitted +in the VBI. V4L2 drivers shall not do this by +software, see also the raw VBI +interface. The data is passed as short packets of fixed size, +covering one scan line each. The number of packets per video frame is +variable. + + Sliced VBI capture and output devices are accessed through the +same character special files as raw VBI devices. When a driver +supports both interfaces, the default function of a +/dev/vbi device is raw VBI +capturing or output, and the sliced VBI function is only available +after calling the &VIDIOC-S-FMT; ioctl as defined below. Likewise a +/dev/video device may support the sliced VBI API, +however the default function here is video capturing or output. +Different file descriptors must be used to pass raw and sliced VBI +data simultaneously, if this is supported by the driver. + +
+ Querying Capabilities + + Devices supporting the sliced VBI capturing or output API +set the V4L2_CAP_SLICED_VBI_CAPTURE or +V4L2_CAP_SLICED_VBI_OUTPUT flag respectively, in +the capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous I/O +methods must be supported. Sliced VBI devices may have a tuner +or modulator. +
+ +
+ Supplemental Functions + + Sliced VBI devices shall support video +input or output and tuner or +modulator ioctls if they have these capabilities, and they may +support control ioctls. The video standard ioctls provide information +vital to program a sliced VBI device, therefore must be +supported. +
+ +
+ Sliced VBI Format Negotiation + + To find out which data services are supported by the +hardware applications can call the &VIDIOC-G-SLICED-VBI-CAP; ioctl. +All drivers implementing the sliced VBI interface must support this +ioctl. The results may differ from those of the &VIDIOC-S-FMT; ioctl +when the number of VBI lines the hardware can capture or output per +frame, or the number of services it can identify on a given line are +limited. For example on PAL line 16 the hardware may be able to look +for a VPS or Teletext signal, but not both at the same time. + + To determine the currently selected services applications +set the type field of &v4l2-format; to + V4L2_BUF_TYPE_SLICED_VBI_CAPTURE or +V4L2_BUF_TYPE_SLICED_VBI_OUTPUT, and the &VIDIOC-G-FMT; +ioctl fills the fmt.sliced member, a +&v4l2-sliced-vbi-format;. + + Applications can request different parameters by +initializing or modifying the fmt.sliced +member and calling the &VIDIOC-S-FMT; ioctl with a pointer to the +v4l2_format structure. + + The sliced VBI API is more complicated than the raw VBI API +because the hardware must be told which VBI service to expect on each +scan line. Not all services may be supported by the hardware on all +lines (this is especially true for VBI output where Teletext is often +unsupported and other services can only be inserted in one specific +line). In many cases, however, it is sufficient to just set the +service_set field to the required services +and let the driver fill the service_lines +array according to hardware capabilities. Only if more precise control +is needed should the programmer set the +service_lines array explicitly. + + The &VIDIOC-S-FMT; ioctl modifies the parameters +according to hardware capabilities. When the driver allocates +resources at this point, it may return an &EBUSY; if the required +resources are temporarily unavailable. Other resource allocation +points which may return EBUSY can be the +&VIDIOC-STREAMON; ioctl and the first &func-read;, &func-write; and +&func-select; call. + + + struct +<structname>v4l2_sliced_vbi_format</structname> + + + + + + + + + + __u32 + service_set + If +service_set is non-zero when passed with +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;, the +service_lines array will be filled by the +driver according to the services specified in this field. For example, +if service_set is initialized with +V4L2_SLICED_TELETEXT_B | V4L2_SLICED_WSS_625, a +driver for the cx25840 video decoder sets lines 7-22 of both +fieldsAccording to ETS 300 706 lines 6-22 of the +first field and lines 5-22 of the second field may carry Teletext +data. to V4L2_SLICED_TELETEXT_B +and line 23 of the first field to +V4L2_SLICED_WSS_625. If +service_set is set to zero, then the values +of service_lines will be used instead. +On return the driver sets this field to the union of all +elements of the returned service_lines +array. It may contain less services than requested, perhaps just one, +if the hardware cannot handle more services simultaneously. It may be +empty (zero) if none of the requested services are supported by the +hardware. + + + __u16 + service_lines[2][24] + Applications initialize this +array with sets of data services the driver shall look for or insert +on the respective scan line. Subject to hardware capabilities drivers +return the requested set, a subset, which may be just a single +service, or an empty set. When the hardware cannot handle multiple +services on the same line the driver shall choose one. No assumptions +can be made on which service the driver chooses.Data +services are defined in . Array indices +map to ITU-R line numbers (see also and ) as follows: + + + + + Element + 525 line systems + 625 line systems + + + + + service_lines[0][1] + 1 + 1 + + + + + service_lines[0][23] + 23 + 23 + + + + + service_lines[1][1] + 264 + 314 + + + + + service_lines[1][23] + 286 + 336 + + + + + + Drivers must set +service_lines[0][0] and +service_lines[1][0] to zero. + + + __u32 + io_size + Maximum number of bytes passed by +one &func-read; or &func-write; call, and the buffer size in bytes for +the &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. Drivers set this field to +the size of &v4l2-sliced-vbi-data; times the number of non-zero +elements in the returned service_lines +array (that is the number of lines potentially carrying data). + + + __u32 + reserved[2] + This array is reserved for future +extensions. Applications and drivers must set it to zero. + + + +
+ + + + Sliced VBI services + + + + + + + + + + Symbol + Value + Reference + Lines, usually + Payload + + + + + V4L2_SLICED_TELETEXT_B +(Teletext System B) + 0x0001 + , + PAL/SECAM line 7-22, 320-335 (second field 7-22) + Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted. + + + V4L2_SLICED_VPS + 0x0400 + + PAL line 16 + Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted. + + + V4L2_SLICED_CAPTION_525 + 0x1000 + + NTSC line 21, 284 (second field 21) + Two bytes in transmission order, including parity +bit, lsb first transmitted. + + + V4L2_SLICED_WSS_625 + 0x4000 + , + PAL/SECAM line 23 + +Byte 0 1 + msb lsb msb lsb + Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 + + + + V4L2_SLICED_VBI_525 + 0x1000 + Set of services applicable to 525 +line systems. + + + V4L2_SLICED_VBI_625 + 0x4401 + Set of services applicable to 625 +line systems. + + + +
+ + Drivers may return an &EINVAL; when applications attempt to +read or write data without prior format negotiation, after switching +the video standard (which may invalidate the negotiated VBI +parameters) and after switching the video input (which may change the +video standard as a side effect). The &VIDIOC-S-FMT; ioctl may return +an &EBUSY; when applications attempt to change the format while i/o is +in progress (between a &VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; call, +and after the first &func-read; or &func-write; call). +
+ +
+ Reading and writing sliced VBI data + + A single &func-read; or &func-write; call must pass all data +belonging to one video frame. That is an array of +v4l2_sliced_vbi_data structures with one or +more elements and a total size not exceeding +io_size bytes. Likewise in streaming I/O +mode one buffer of io_size bytes must +contain data of one video frame. The id of +unused v4l2_sliced_vbi_data elements must be +zero. + + + struct +<structname>v4l2_sliced_vbi_data</structname> + + &cs-def; + + + __u32 + id + A flag from +identifying the type of data in this packet. Only a single bit must be +set. When the id of a captured packet is +zero, the packet is empty and the contents of other fields are +undefined. Applications shall ignore empty packets. When the +id of a packet for output is zero the +contents of the data field are undefined +and the driver must no longer insert data on the requested +field and +line. + + + __u32 + field + The video field number this data has been captured +from, or shall be inserted at. 0 for the first +field, 1 for the second field. + + + __u32 + line + The field (as opposed to frame) line number this +data has been captured from, or shall be inserted at. See and for valid +values. Sliced VBI capture devices can set the line number of all +packets to 0 if the hardware cannot reliably +identify scan lines. The field number must always be valid. + + + __u32 + reserved + This field is reserved for future extensions. +Applications and drivers must set it to zero. + + + __u8 + data[48] + The packet payload. See for the contents and number of +bytes passed for each data type. The contents of padding bytes at the +end of this array are undefined, drivers and applications shall ignore +them. + + + +
+ + Packets are always passed in ascending line number order, +without duplicate line numbers. The &func-write; function and the +&VIDIOC-QBUF; ioctl must return an &EINVAL; when applications violate +this rule. They must also return an &EINVAL; when applications pass an +incorrect field or line number, or a combination of +field, line and +id which has not been negotiated with the +&VIDIOC-G-FMT; or &VIDIOC-S-FMT; ioctl. When the line numbers are +unknown the driver must pass the packets in transmitted order. The +driver can insert empty packets with id set +to zero anywhere in the packet array. + + To assure synchronization and to distinguish from frame +dropping, when a captured frame does not carry any of the requested +data services drivers must pass one or more empty packets. When an +application fails to pass VBI data in time for output, the driver +must output the last VPS and WSS packet again, and disable the output +of Closed Caption and Teletext data, or output data which is ignored +by Closed Caption and Teletext decoders. + + A sliced VBI device may support read/write and/or streaming (memory mapping and/or user +pointer) I/O. The latter bears the possibility of synchronizing +video and VBI data by using buffer timestamps. + +
+ +
+ Sliced VBI Data in MPEG Streams + + If a device can produce an MPEG output stream, it may be +capable of providing negotiated sliced VBI +services as data embedded in the MPEG stream. Users or +applications control this sliced VBI data insertion with the V4L2_CID_MPEG_STREAM_VBI_FMT +control. + + If the driver does not provide the V4L2_CID_MPEG_STREAM_VBI_FMT +control, or only allows that control to be set to +V4L2_MPEG_STREAM_VBI_FMT_NONE, then the device +cannot embed sliced VBI data in the MPEG stream. + + The +V4L2_CID_MPEG_STREAM_VBI_FMT control does not implicitly set +the device driver to capture nor cease capturing sliced VBI data. The +control only indicates to embed sliced VBI data in the MPEG stream, if +an application has negotiated sliced VBI service be captured. + + It may also be the case that a device can embed sliced VBI +data in only certain types of MPEG streams: for example in an MPEG-2 +PS but not an MPEG-2 TS. In this situation, if sliced VBI data +insertion is requested, the sliced VBI data will be embedded in MPEG +stream types when supported, and silently omitted from MPEG stream +types where sliced VBI data insertion is not supported by the device. + + + The following subsections specify the format of the +embedded sliced VBI data. + +
+ MPEG Stream Embedded, Sliced VBI Data Format: NONE + The +V4L2_MPEG_STREAM_VBI_FMT_NONE embedded sliced VBI +format shall be interpreted by drivers as a control to cease +embedding sliced VBI data in MPEG streams. Neither the device nor +driver shall insert "empty" embedded sliced VBI data packets in the +MPEG stream when this format is set. No MPEG stream data structures +are specified for this format. +
+ +
+ MPEG Stream Embedded, Sliced VBI Data Format: IVTV + The +V4L2_MPEG_STREAM_VBI_FMT_IVTV embedded sliced VBI +format, when supported, indicates to the driver to embed up to 36 +lines of sliced VBI data per frame in an MPEG-2 Private +Stream 1 PES packet encapsulated in an MPEG-2 +Program Pack in the MPEG stream. + + Historical context: This format +specification originates from a custom, embedded, sliced VBI data +format used by the ivtv driver. This format +has already been informally specified in the kernel sources in the +file Documentation/video4linux/cx2341x/README.vbi +. The maximum size of the payload and other aspects of this format +are driven by the CX23415 MPEG decoder's capabilities and limitations +with respect to extracting, decoding, and displaying sliced VBI data +embedded within an MPEG stream. + + This format's use is not exclusive to +the ivtv driver nor +exclusive to CX2341x devices, as the sliced VBI data packet insertion +into the MPEG stream is implemented in driver software. At least the +cx18 driver provides sliced VBI data insertion +into an MPEG-2 PS in this format as well. + + The following definitions specify the payload of the +MPEG-2 Private Stream 1 PES packets that contain +sliced VBI data when +V4L2_MPEG_STREAM_VBI_FMT_IVTV is set. +(The MPEG-2 Private Stream 1 PES packet header +and encapsulating MPEG-2 Program Pack header are +not detailed here. Please refer to the MPEG-2 specifications for +details on those packet headers.) + + The payload of the MPEG-2 Private Stream 1 PES + packets that contain sliced VBI data is specified by +&v4l2-mpeg-vbi-fmt-ivtv;. The payload is variable +length, depending on the actual number of lines of sliced VBI data +present in a video frame. The payload may be padded at the end with +unspecified fill bytes to align the end of the payload to a 4-byte +boundary. The payload shall never exceed 1552 bytes (2 fields with +18 lines/field with 43 bytes of data/line and a 4 byte magic number). + + + + struct <structname>v4l2_mpeg_vbi_fmt_ivtv</structname> + + + &cs-ustr; + + + __u8 + magic[4] + + A "magic" constant from that indicates +this is a valid sliced VBI data payload and also indicates which +member of the anonymous union, itv0 or +ITV0, to use for the payload data. + + + union + (anonymous) + + + + struct + v4l2_mpeg_vbi_itv0 + + itv0 + The primary form of the sliced VBI data payload +that contains anywhere from 1 to 35 lines of sliced VBI data. +Line masks are provided in this form of the payload indicating +which VBI lines are provided. + + + + struct + v4l2_mpeg_vbi_ITV0 + + ITV0 + An alternate form of the sliced VBI data payload +used when 36 lines of sliced VBI data are present. No line masks are +provided in this form of the payload; all valid line mask bits are +implcitly set. + + + +
+ + + Magic Constants for &v4l2-mpeg-vbi-fmt-ivtv; + <structfield>magic</structfield> field + + &cs-def; + + + Defined Symbol + Value + Description + + + + + V4L2_MPEG_VBI_IVTV_MAGIC0 + + "itv0" + Indicates the itv0 +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid. + + + V4L2_MPEG_VBI_IVTV_MAGIC1 + + "ITV0" + Indicates the ITV0 +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid and +that 36 lines of sliced VBI data are present. + + + +
+ + + struct <structname>v4l2_mpeg_vbi_itv0</structname> + + + &cs-str; + + + __le32 + linemask[2] + Bitmasks indicating the VBI service lines +present. These linemask values are stored +in little endian byte order in the MPEG stream. Some reference +linemask bit positions with their +corresponding VBI line number and video field are given below. +b0 indicates the least significant bit of a +linemask value: +linemask[0] b0: line 6 first field +linemask[0] b17: line 23 first field +linemask[0] b18: line 6 second field +linemask[0] b31: line 19 second field +linemask[1] b0: line 20 second field +linemask[1] b3: line 23 second field +linemask[1] b4-b31: unused and set to 0 + + + struct + v4l2_mpeg_vbi_itv0_line + + line[35] + This is a variable length array that holds from 1 +to 35 lines of sliced VBI data. The sliced VBI data lines present +correspond to the bits set in the linemask +array, starting from b0 of +linemask[0] up through b31 of +linemask[0], and from b0 + of linemask[1] up through b +3 of linemask[1]. +line[0] corresponds to the first bit +found set in the linemask array, +line[1] corresponds to the second bit +found set in the linemask array, etc. +If no linemask array bits are set, then +line[0] may contain one line of +unspecified data that should be ignored by applications. + + + +
+ + + struct <structname>v4l2_mpeg_vbi_ITV0</structname> + + + &cs-str; + + + struct + v4l2_mpeg_vbi_itv0_line + + line[36] + A fixed length array of 36 lines of sliced VBI +data. line[0] through line +[17] correspond to lines 6 through 23 of the +first field. line[18] through +line[35] corresponds to lines 6 +through 23 of the second field. + + + +
+ + + struct <structname>v4l2_mpeg_vbi_itv0_line</structname> + + + &cs-str; + + + __u8 + id + A line identifier value from + that indicates +the type of sliced VBI data stored on this line. + + + __u8 + data[42] + The sliced VBI data for the line. + + + +
+ + + Line Identifiers for struct <link + linkend="v4l2-mpeg-vbi-itv0-line"><structname> +v4l2_mpeg_vbi_itv0_line</structname></link> <structfield>id +</structfield> field + + &cs-def; + + + Defined Symbol + Value + Description + + + + + V4L2_MPEG_VBI_IVTV_TELETEXT_B + + 1 + Refer to +Sliced VBI services for a description of the line payload. + + + V4L2_MPEG_VBI_IVTV_CAPTION_525 + + 4 + Refer to +Sliced VBI services for a description of the line payload. + + + V4L2_MPEG_VBI_IVTV_WSS_625 + + 5 + Refer to +Sliced VBI services for a description of the line payload. + + + V4L2_MPEG_VBI_IVTV_VPS + + 7 + Refer to +Sliced VBI services for a description of the line payload. + + + +
+ +
+
+ + + diff --git a/Documentation/DocBook/media/v4l/dev-subdev.xml b/Documentation/DocBook/media/v4l/dev-subdev.xml new file mode 100644 index 00000000000..05c8fefcbcb --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-subdev.xml @@ -0,0 +1,313 @@ + Sub-device Interface + + + Experimental + This is an experimental + interface and may change in the future. + + + The complex nature of V4L2 devices, where hardware is often made of + several integrated circuits that need to interact with each other in a + controlled way, leads to complex V4L2 drivers. The drivers usually reflect + the hardware model in software, and model the different hardware components + as software blocks called sub-devices. + + V4L2 sub-devices are usually kernel-only objects. If the V4L2 driver + implements the media device API, they will automatically inherit from media + entities. Applications will be able to enumerate the sub-devices and discover + the hardware topology using the media entities, pads and links enumeration + API. + + In addition to make sub-devices discoverable, drivers can also choose + to make them directly configurable by applications. When both the sub-device + driver and the V4L2 device driver support this, sub-devices will feature a + character device node on which ioctls can be called to + + query, read and write sub-devices controls + subscribe and unsubscribe to events and retrieve them + negotiate image formats on individual pads + + + + Sub-device character device nodes, conventionally named + /dev/v4l-subdev*, use major number 81. + +
+ Controls + Most V4L2 controls are implemented by sub-device hardware. Drivers + usually merge all controls and expose them through video device nodes. + Applications can control all sub-devices through a single interface. + + Complex devices sometimes implement the same control in different + pieces of hardware. This situation is common in embedded platforms, where + both sensors and image processing hardware implement identical functions, + such as contrast adjustment, white balance or faulty pixels correction. As + the V4L2 controls API doesn't support several identical controls in a single + device, all but one of the identical controls are hidden. + + Applications can access those hidden controls through the sub-device + node with the V4L2 control API described in . The + ioctls behave identically as when issued on V4L2 device nodes, with the + exception that they deal only with controls implemented in the sub-device. + + + Depending on the driver, those controls might also be exposed through + one (or several) V4L2 device nodes. +
+ +
+ Events + V4L2 sub-devices can notify applications of events as described in + . The API behaves identically as when used on V4L2 + device nodes, with the exception that it only deals with events generated by + the sub-device. Depending on the driver, those events might also be reported + on one (or several) V4L2 device nodes. +
+ +
+ Pad-level Formats + + Pad-level formats are only applicable to very complex device that + need to expose low-level format configuration to user space. Generic V4L2 + applications do not need to use the API described in + this section. + + For the purpose of this section, the term + format means the combination of media bus data + format, frame width and frame height. + + Image formats are typically negotiated on video capture and output + devices using the cropping and scaling ioctls. + The driver is responsible for configuring every block in the video pipeline + according to the requested format at the pipeline input and/or + output. + + For complex devices, such as often found in embedded systems, + identical image sizes at the output of a pipeline can be achieved using + different hardware configurations. One such example is shown on + , where + image scaling can be performed on both the video sensor and the host image + processing hardware. + +
+ Image Format Negotiation on Pipelines + + + + + + + + + High quality and high speed pipeline configuration + + +
+ + The sensor scaler is usually of less quality than the host scaler, but + scaling on the sensor is required to achieve higher frame rates. Depending + on the use case (quality vs. speed), the pipeline must be configured + differently. Applications need to configure the formats at every point in + the pipeline explicitly. + + Drivers that implement the media + API can expose pad-level image format configuration to applications. + When they do, applications can use the &VIDIOC-SUBDEV-G-FMT; and + &VIDIOC-SUBDEV-S-FMT; ioctls. to negotiate formats on a per-pad basis. + + Applications are responsible for configuring coherent parameters on + the whole pipeline and making sure that connected pads have compatible + formats. The pipeline is checked for formats mismatch at &VIDIOC-STREAMON; + time, and an &EPIPE; is then returned if the configuration is + invalid. + + Pad-level image format configuration support can be tested by calling + the &VIDIOC-SUBDEV-G-FMT; ioctl on pad 0. If the driver returns an &EINVAL; + pad-level format configuration is not supported by the sub-device. + +
+ Format Negotiation + + Acceptable formats on pads can (and usually do) depend on a number + of external parameters, such as formats on other pads, active links, or + even controls. Finding a combination of formats on all pads in a video + pipeline, acceptable to both application and driver, can't rely on formats + enumeration only. A format negotiation mechanism is required. + + Central to the format negotiation mechanism are the get/set format + operations. When called with the which argument + set to V4L2_SUBDEV_FORMAT_TRY, the + &VIDIOC-SUBDEV-G-FMT; and &VIDIOC-SUBDEV-S-FMT; ioctls operate on a set of + formats parameters that are not connected to the hardware configuration. + Modifying those 'try' formats leaves the device state untouched (this + applies to both the software state stored in the driver and the hardware + state stored in the device itself). + + While not kept as part of the device state, try formats are stored + in the sub-device file handles. A &VIDIOC-SUBDEV-G-FMT; call will return + the last try format set on the same sub-device file + handle. Several applications querying the same sub-device at + the same time will thus not interact with each other. + + To find out whether a particular format is supported by the device, + applications use the &VIDIOC-SUBDEV-S-FMT; ioctl. Drivers verify and, if + needed, change the requested format based on + device requirements and return the possibly modified value. Applications + can then choose to try a different format or accept the returned value and + continue. + + Formats returned by the driver during a negotiation iteration are + guaranteed to be supported by the device. In particular, drivers guarantee + that a returned format will not be further changed if passed to an + &VIDIOC-SUBDEV-S-FMT; call as-is (as long as external parameters, such as + formats on other pads or links' configuration are not changed). + + Drivers automatically propagate formats inside sub-devices. When a + try or active format is set on a pad, corresponding formats on other pads + of the same sub-device can be modified by the driver. Drivers are free to + modify formats as required by the device. However, they should comply with + the following rules when possible: + + Formats should be propagated from sink pads to source pads. + Modifying a format on a source pad should not modify the format on any + sink pad. + Sub-devices that scale frames using variable scaling factors + should reset the scale factors to default values when sink pads formats + are modified. If the 1:1 scaling ratio is supported, this means that + source pads formats should be reset to the sink pads formats. + + + + Formats are not propagated across links, as that would involve + propagating them from one sub-device file handle to another. Applications + must then take care to configure both ends of every link explicitly with + compatible formats. Identical formats on the two ends of a link are + guaranteed to be compatible. Drivers are free to accept different formats + matching device requirements as being compatible. + + + shows a sample configuration sequence for the pipeline described in + (table + columns list entity names and pad numbers). + + + Sample Pipeline Configuration + + + + + + + + + + + Sensor/0 + Frontend/0 + Frontend/1 + Scaler/0 + Scaler/1 + + + + + Initial state + 2048x1536 + - + - + - + - + + + Configure frontend input + 2048x1536 + 2048x1536 + 2046x1534 + - + - + + + Configure scaler input + 2048x1536 + 2048x1536 + 2046x1534 + 2046x1534 + 2046x1534 + + + Configure scaler output + 2048x1536 + 2048x1536 + 2046x1534 + 2046x1534 + 1280x960 + + + +
+ + + + Initial state. The sensor output is set to its native 3MP + resolution. Resolutions on the host frontend and scaler input and output + pads are undefined. + The application configures the frontend input pad resolution to + 2048x1536. The driver propagates the format to the frontend output pad. + Note that the propagated output format can be different, as in this case, + than the input format, as the hardware might need to crop pixels (for + instance when converting a Bayer filter pattern to RGB or YUV). + The application configures the scaler input pad resolution to + 2046x1534 to match the frontend output resolution. The driver propagates + the format to the scaler output pad. + The application configures the scaler output pad resolution to + 1280x960. + + + + When satisfied with the try results, applications can set the active + formats by setting the which argument to + V4L2_SUBDEV_FORMAT_TRY. Active formats are changed + exactly as try formats by drivers. To avoid modifying the hardware state + during format negotiation, applications should negotiate try formats first + and then modify the active settings using the try formats returned during + the last negotiation iteration. This guarantees that the active format + will be applied as-is by the driver without being modified. + +
+ +
+ Cropping and scaling + + Many sub-devices support cropping frames on their input or output + pads (or possible even on both). Cropping is used to select the area of + interest in an image, typically on a video sensor or video decoder. It can + also be used as part of digital zoom implementations to select the area of + the image that will be scaled up. + + Crop settings are defined by a crop rectangle and represented in a + &v4l2-rect; by the coordinates of the top left corner and the rectangle + size. Both the coordinates and sizes are expressed in pixels. + + The crop rectangle is retrieved and set using the + &VIDIOC-SUBDEV-G-CROP; and &VIDIOC-SUBDEV-S-CROP; ioctls. Like for pad + formats, drivers store try and active crop rectangles. The format + negotiation mechanism applies to crop settings as well. + + On input pads, cropping is applied relatively to the current pad + format. The pad format represents the image size as received by the + sub-device from the previous block in the pipeline, and the crop rectangle + represents the sub-image that will be transmitted further inside the + sub-device for processing. The crop rectangle be entirely containted + inside the input image size. + + Input crop rectangle are reset to their default value when the input + image format is modified. Drivers should use the input image size as the + crop rectangle default value, but hardware requirements may prevent this. + + + Cropping behaviour on output pads is not defined. + +
+
+ + &sub-subdev-formats; diff --git a/Documentation/DocBook/media/v4l/dev-teletext.xml b/Documentation/DocBook/media/v4l/dev-teletext.xml new file mode 100644 index 00000000000..414b1cfff9f --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-teletext.xml @@ -0,0 +1,37 @@ + Teletext Interface + + This interface was aimed at devices receiving and demodulating +Teletext data [, ], evaluating the +Teletext packages and storing formatted pages in cache memory. Such +devices are usually implemented as microcontrollers with serial +interface (I2C) and could be found on old +TV cards, dedicated Teletext decoding cards and home-brew devices +connected to the PC parallel port. + + The Teletext API was designed by Martin Buck. It was defined in +the kernel header file linux/videotext.h, the +specification is available from +ftp://ftp.gwdg.de/pub/linux/misc/videotext/. (Videotext is the name of +the German public television Teletext service.) + + Eventually the Teletext API was integrated into the V4L API +with character device file names /dev/vtx0 to +/dev/vtx31, device major number 81, minor numbers +192 to 223. + + However, teletext decoders were quickly replaced by more +generic VBI demodulators and those dedicated teletext decoders no longer exist. +For many years the vtx devices were still around, even though nobody used +them. So the decision was made to finally remove support for the Teletext API in +kernel 2.6.37. + + Modern devices all use the raw or +sliced VBI API. + + diff --git a/Documentation/DocBook/media/v4l/driver.xml b/Documentation/DocBook/media/v4l/driver.xml new file mode 100644 index 00000000000..1f7eea5c4ec --- /dev/null +++ b/Documentation/DocBook/media/v4l/driver.xml @@ -0,0 +1,208 @@ + V4L2 Driver Programming + + + + to do + + + diff --git a/Documentation/DocBook/media/v4l/fdl-appendix.xml b/Documentation/DocBook/media/v4l/fdl-appendix.xml new file mode 100644 index 00000000000..ae22394ba99 --- /dev/null +++ b/Documentation/DocBook/media/v4l/fdl-appendix.xml @@ -0,0 +1,671 @@ + + + + + + Version 1.1, March 2000 + + + 2000Free Software Foundation, Inc. + + + +
Free Software Foundation, Inc. 59 Temple Place, + Suite 330, Boston, MA + 02111-1307 USA
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If you have no + Front-Cover Texts, write + no Front-Cover Texts instead of + Front-Cover Texts being LIST; likewise for Back-Cover Texts. + + + + If your document contains nontrivial examples of program code, + we recommend releasing these examples in parallel under your + choice of free software license, such as the GNU General Public + License, to permit their use in free software. + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/fieldseq_bt.gif b/Documentation/DocBook/media/v4l/fieldseq_bt.gif new file mode 100644 index 00000000000..60e8569a76c Binary files /dev/null and b/Documentation/DocBook/media/v4l/fieldseq_bt.gif differ diff --git a/Documentation/DocBook/media/v4l/fieldseq_bt.pdf b/Documentation/DocBook/media/v4l/fieldseq_bt.pdf new file mode 100644 index 00000000000..26598b23f80 Binary files /dev/null and b/Documentation/DocBook/media/v4l/fieldseq_bt.pdf differ diff --git a/Documentation/DocBook/media/v4l/fieldseq_tb.gif b/Documentation/DocBook/media/v4l/fieldseq_tb.gif new file mode 100644 index 00000000000..718492f1cfc Binary files /dev/null and b/Documentation/DocBook/media/v4l/fieldseq_tb.gif differ diff --git a/Documentation/DocBook/media/v4l/fieldseq_tb.pdf b/Documentation/DocBook/media/v4l/fieldseq_tb.pdf new file mode 100644 index 00000000000..4965b22ddb3 Binary files /dev/null and b/Documentation/DocBook/media/v4l/fieldseq_tb.pdf differ diff --git a/Documentation/DocBook/media/v4l/func-close.xml b/Documentation/DocBook/media/v4l/func-close.xml new file mode 100644 index 00000000000..dfb41cbbbec --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-close.xml @@ -0,0 +1,70 @@ + + + V4L2 close() + &manvol; + + + + v4l2-close + Close a V4L2 device + + + + + #include <unistd.h> + + int close + int fd + + + + + + Arguments + + + + fd + + &fd; + + + + + + + Description + + Closes the device. Any I/O in progress is terminated and +resources associated with the file descriptor are freed. However data +format parameters, current input or output, control values or other +properties remain unchanged. + + + + Return Value + + The function returns 0 on +success, -1 on failure and the +errno is set appropriately. Possible error +codes: + + + + EBADF + + fd is not a valid open file +descriptor. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-ioctl.xml b/Documentation/DocBook/media/v4l/func-ioctl.xml new file mode 100644 index 00000000000..b60fd37a629 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-ioctl.xml @@ -0,0 +1,145 @@ + + + V4L2 ioctl() + &manvol; + + + + v4l2-ioctl + Program a V4L2 device + + + + + #include <sys/ioctl.h> + + int ioctl + int fd + int request + void *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + V4L2 ioctl request code as defined in the videodev2.h header file, for example +VIDIOC_QUERYCAP. + + + + argp + + Pointer to a function parameter, usually a structure. + + + + + + + Description + + The ioctl() function is used to program +V4L2 devices. The argument fd must be an open +file descriptor. An ioctl request has encoded +in it whether the argument is an input, output or read/write +parameter, and the size of the argument argp in +bytes. Macros and defines specifying V4L2 ioctl requests are located +in the videodev2.h header file. +Applications should use their own copy, not include the version in the +kernel sources on the system they compile on. All V4L2 ioctl requests, +their respective function and parameters are specified in . + + + + Return Value + + On success the ioctl() function returns +0 and does not reset the +errno variable. On failure +-1 is returned, when the ioctl takes an +output or read/write parameter it remains unmodified, and the +errno variable is set appropriately. See below for +possible error codes. Generic errors like EBADF +or EFAULT are not listed in the sections +discussing individual ioctl requests. + Note ioctls may return undefined error codes. Since errors +may have side effects such as a driver reset applications should +abort on unexpected errors. + + + + EBADF + + fd is not a valid open file +descriptor. + + + + EBUSY + + The property cannot be changed right now. Typically +this error code is returned when I/O is in progress or the driver +supports multiple opens and another process locked the property. + + + + EFAULT + + argp references an inaccessible +memory area. + + + + ENOTTY + + fd is not associated with a +character special device. + + + + EINVAL + + The request or the data pointed +to by argp is not valid. This is a very common +error code, see the individual ioctl requests listed in for actual causes. + + + + ENOMEM + + Not enough physical or virtual memory was available to +complete the request. + + + + ERANGE + + The application attempted to set a control with the +&VIDIOC-S-CTRL; ioctl to a value which is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-mmap.xml b/Documentation/DocBook/media/v4l/func-mmap.xml new file mode 100644 index 00000000000..786732b64bb --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-mmap.xml @@ -0,0 +1,191 @@ + + + V4L2 mmap() + &manvol; + + + + v4l2-mmap + Map device memory into application address space + + + + + +#include <unistd.h> +#include <sys/mman.h> + + void *mmap + void *start + size_t length + int prot + int flags + int fd + off_t offset + + + + + + Arguments + + + start + + Map the buffer to this address in the +application's address space. When the MAP_FIXED +flag is specified, start must be a multiple of the +pagesize and mmap will fail when the specified address +cannot be used. Use of this option is discouraged; applications should +just specify a NULL pointer here. + + + + length + + Length of the memory area to map. This must be the +same value as returned by the driver in the &v4l2-buffer; +length field for the +single-planar API, and the same value as returned by the driver +in the &v4l2-plane; length field for the +multi-planar API. + + + + prot + + The prot argument describes the +desired memory protection. Regardless of the device type and the +direction of data exchange it should be set to +PROT_READ | PROT_WRITE, +permitting read and write access to image buffers. Drivers should +support at least this combination of flags. Note the Linux +video-buf kernel module, which is used by the +bttv, saa7134, saa7146, cx88 and vivi driver supports only +PROT_READ | PROT_WRITE. When +the driver does not support the desired protection the +mmap() function fails. + Note device memory accesses (⪚ the memory on a +graphics card with video capturing hardware) may incur a performance +penalty compared to main memory accesses, or reads may be +significantly slower than writes or vice versa. Other I/O methods may +be more efficient in this case. + + + + flags + + The flags parameter +specifies the type of the mapped object, mapping options and whether +modifications made to the mapped copy of the page are private to the +process or are to be shared with other references. + MAP_FIXED requests that the +driver selects no other address than the one specified. If the +specified address cannot be used, mmap() will fail. If +MAP_FIXED is specified, +start must be a multiple of the pagesize. Use +of this option is discouraged. + One of the MAP_SHARED or +MAP_PRIVATE flags must be set. +MAP_SHARED allows applications to share the +mapped memory with other (⪚ child-) processes. Note the Linux +video-buf module which is used by the bttv, +saa7134, saa7146, cx88 and vivi driver supports only +MAP_SHARED. MAP_PRIVATE +requests copy-on-write semantics. V4L2 applications should not set the +MAP_PRIVATE, MAP_DENYWRITE, +MAP_EXECUTABLE or MAP_ANON +flag. + + + + fd + + &fd; + + + + offset + + Offset of the buffer in device memory. This must be the +same value as returned by the driver in the &v4l2-buffer; +m union offset field for +the single-planar API, and the same value as returned by the driver +in the &v4l2-plane; m union +mem_offset field for the multi-planar API. + + + + + + + Description + + The mmap() function asks to map +length bytes starting at +offset in the memory of the device specified by +fd into the application address space, +preferably at address start. This latter +address is a hint only, and is usually specified as 0. + + Suitable length and offset parameters are queried with the +&VIDIOC-QUERYBUF; ioctl. Buffers must be allocated with the +&VIDIOC-REQBUFS; ioctl before they can be queried. + + To unmap buffers the &func-munmap; function is used. + + + + Return Value + + On success mmap() returns a pointer to +the mapped buffer. On error MAP_FAILED (-1) is +returned, and the errno variable is set +appropriately. Possible error codes are: + + + + EBADF + + fd is not a valid file +descriptor. + + + + EACCES + + fd is +not open for reading and writing. + + + + EINVAL + + The start or +length or offset are not +suitable. (E. g. they are too large, or not aligned on a +PAGESIZE boundary.) + The flags or +prot value is not supported. + No buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl. + + + + ENOMEM + + Not enough physical or virtual memory was available to +complete the request. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-munmap.xml b/Documentation/DocBook/media/v4l/func-munmap.xml new file mode 100644 index 00000000000..e2c4190f9bb --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-munmap.xml @@ -0,0 +1,84 @@ + + + V4L2 munmap() + &manvol; + + + + v4l2-munmap + Unmap device memory + + + + + +#include <unistd.h> +#include <sys/mman.h> + + int munmap + void *start + size_t length + + + + + Arguments + + + start + + Address of the mapped buffer as returned by the +&func-mmap; function. + + + + length + + Length of the mapped buffer. This must be the same +value as given to mmap() and returned by the +driver in the &v4l2-buffer; length +field for the single-planar API and in the &v4l2-plane; +length field for the multi-planar API. + + + + + + + Description + + Unmaps a previously with the &func-mmap; function mapped +buffer and frees it, if possible. + + + + Return Value + + On success munmap() returns 0, on +failure -1 and the errno variable is set +appropriately: + + + + EINVAL + + The start or +length is incorrect, or no buffers have been +mapped yet. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-open.xml b/Documentation/DocBook/media/v4l/func-open.xml new file mode 100644 index 00000000000..7595d07a8c7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-open.xml @@ -0,0 +1,121 @@ + + + V4L2 open() + &manvol; + + + + v4l2-open + Open a V4L2 device + + + + + #include <fcntl.h> + + int open + const char *device_name + int flags + + + + + + Arguments + + + + device_name + + Device to be opened. + + + + flags + + Open flags. Access mode must be +O_RDWR. This is just a technicality, input devices +still support only reading and output devices only writing. + When the O_NONBLOCK flag is +given, the read() function and the &VIDIOC-DQBUF; ioctl will return +the &EAGAIN; when no data is available or no buffer is in the driver +outgoing queue, otherwise these functions block until data becomes +available. All V4L2 drivers exchanging data with applications must +support the O_NONBLOCK flag. + Other flags have no effect. + + + + + + Description + + To open a V4L2 device applications call +open() with the desired device name. This +function has no side effects; all data format parameters, current +input or output, control values or other properties remain unchanged. +At the first open() call after loading the driver +they will be reset to default values, drivers are never in an +undefined state. + + + Return Value + + On success open returns the new file +descriptor. On error -1 is returned, and the errno +variable is set appropriately. Possible error codes are: + + + + EACCES + + The caller has no permission to access the +device. + + + + EBUSY + + The driver does not support multiple opens and the +device is already in use. + + + + ENXIO + + No device corresponding to this device special file +exists. + + + + ENOMEM + + Not enough kernel memory was available to complete the +request. + + + + EMFILE + + The process already has the maximum number of +files open. + + + + ENFILE + + The limit on the total number of files open on the +system has been reached. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-poll.xml b/Documentation/DocBook/media/v4l/func-poll.xml new file mode 100644 index 00000000000..ec3c718f596 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-poll.xml @@ -0,0 +1,127 @@ + + + V4L2 poll() + &manvol; + + + + v4l2-poll + Wait for some event on a file descriptor + + + + + #include <sys/poll.h> + + int poll + struct pollfd *ufds + unsigned int nfds + int timeout + + + + + + Description + + With the poll() function applications +can suspend execution until the driver has captured data or is ready +to accept data for output. + + When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately. + + On success poll() returns the number of +file descriptors that have been selected (that is, file descriptors +for which the revents field of the +respective pollfd structure is non-zero). +Capture devices set the POLLIN and +POLLRDNORM flags in the +revents field, output devices the +POLLOUT and POLLWRNORM +flags. When the function timed out it returns a value of zero, on +failure it returns -1 and the +errno variable is set appropriately. When the +application did not call &VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +poll() function succeeds, but sets the +POLLERR flag in the +revents field. + + When use of the read() function has +been negotiated and the driver does not capture yet, the +poll function starts capturing. When that fails +it returns a POLLERR as above. Otherwise it waits +until data has been captured and can be read. When the driver captures +continuously (as opposed to, for example, still images) the function +may return immediately. + + When use of the write() function has +been negotiated the poll function just waits +until the driver is ready for a non-blocking +write() call. + + All drivers implementing the read() or +write() function or streaming I/O must also +support the poll() function. + + For more details see the +poll() manual page. + + + + Return Value + + On success, poll() returns the number +structures which have non-zero revents +fields, or zero if the call timed out. On error +-1 is returned, and the +errno variable is set appropriately: + + + + EBADF + + One or more of the ufds members +specify an invalid file descriptor. + + + + EBUSY + + The driver does not support multiple read or write +streams and the device is already in use. + + + + EFAULT + + ufds references an inaccessible +memory area. + + + + EINTR + + The call was interrupted by a signal. + + + + EINVAL + + The nfds argument is greater +than OPEN_MAX. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-read.xml b/Documentation/DocBook/media/v4l/func-read.xml new file mode 100644 index 00000000000..a5089bf8873 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-read.xml @@ -0,0 +1,189 @@ + + + V4L2 read() + &manvol; + + + + v4l2-read + Read from a V4L2 device + + + + + #include <unistd.h> + + ssize_t read + int fd + void *buf + size_t count + + + + + + Arguments + + + + fd + + &fd; + + + + buf + + + + + + count + + + + + + + + + Description + + read() attempts to read up to +count bytes from file descriptor +fd into the buffer starting at +buf. The layout of the data in the buffer is +discussed in the respective device interface section, see ##. If count is zero, +read() returns zero and has no other results. If +count is greater than +SSIZE_MAX, the result is unspecified. Regardless +of the count value each +read() call will provide at most one frame (two +fields) worth of data. + + By default read() blocks until data +becomes available. When the O_NONBLOCK flag was +given to the &func-open; function it +returns immediately with an &EAGAIN; when no data is available. The +&func-select; or &func-poll; functions +can always be used to suspend execution until data becomes available. All +drivers supporting the read() function must also +support select() and +poll(). + + Drivers can implement read functionality in different +ways, using a single or multiple buffers and discarding the oldest or +newest frames once the internal buffers are filled. + + read() never returns a "snapshot" of a +buffer being filled. Using a single buffer the driver will stop +capturing when the application starts reading the buffer until the +read is finished. Thus only the period of the vertical blanking +interval is available for reading, or the capture rate must fall below +the nominal frame rate of the video standard. + +The behavior of +read() when called during the active picture +period or the vertical blanking separating the top and bottom field +depends on the discarding policy. A driver discarding the oldest +frames keeps capturing into an internal buffer, continuously +overwriting the previously, not read frame, and returns the frame +being received at the time of the read() call as +soon as it is complete. + + A driver discarding the newest frames stops capturing until +the next read() call. The frame being received at +read() time is discarded, returning the following +frame instead. Again this implies a reduction of the capture rate to +one half or less of the nominal frame rate. An example of this model +is the video read mode of the bttv driver, initiating a DMA to user +memory when read() is called and returning when +the DMA finished. + + In the multiple buffer model drivers maintain a ring of +internal buffers, automatically advancing to the next free buffer. +This allows continuous capturing when the application can empty the +buffers fast enough. Again, the behavior when the driver runs out of +free buffers depends on the discarding policy. + + Applications can get and set the number of buffers used +internally by the driver with the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; +ioctls. They are optional, however. The discarding policy is not +reported and cannot be changed. For minimum requirements see . + + + + Return Value + + On success, the number of bytes read is returned. It is not +an error if this number is smaller than the number of bytes requested, +or the amount of data required for one frame. This may happen for +example because read() was interrupted by a +signal. On error, -1 is returned, and the errno +variable is set appropriately. In this case the next read will start +at the beginning of a new frame. Possible error codes are: + + + + EAGAIN + + Non-blocking I/O has been selected using +O_NONBLOCK and no data was immediately available for reading. + + + + EBADF + + fd is not a valid file +descriptor or is not open for reading, or the process already has the +maximum number of files open. + + + + EBUSY + + The driver does not support multiple read streams and the +device is already in use. + + + + EFAULT + + buf references an inaccessible +memory area. + + + + EINTR + + The call was interrupted by a signal before any +data was read. + + + + EIO + + I/O error. This indicates some hardware problem or a +failure to communicate with a remote device (USB camera etc.). + + + + EINVAL + + The read() function is not +supported by this driver, not on this device, or generally not on this +type of device. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-select.xml b/Documentation/DocBook/media/v4l/func-select.xml new file mode 100644 index 00000000000..b6713623181 --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-select.xml @@ -0,0 +1,138 @@ + + + V4L2 select() + &manvol; + + + + v4l2-select + Synchronous I/O multiplexing + + + + + +#include <sys/time.h> +#include <sys/types.h> +#include <unistd.h> + + int select + int nfds + fd_set *readfds + fd_set *writefds + fd_set *exceptfds + struct timeval *timeout + + + + + + Description + + With the select() function applications +can suspend execution until the driver has captured data or is ready +to accept data for output. + + When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately. + + On success select() returns the total +number of bits set in the fd_sets. When the +function timed out it returns a value of zero. On failure it returns +-1 and the errno +variable is set appropriately. When the application did not call +&VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +select() function succeeds, setting the bit of +the file descriptor in readfds or +writefds, but subsequent &VIDIOC-DQBUF; calls +will fail.The Linux kernel implements +select() like the &func-poll; function, but +select() cannot return a +POLLERR. + + + When use of the read() function has +been negotiated and the driver does not capture yet, the +select() function starts capturing. When that +fails, select() returns successful and a +subsequent read() call, which also attempts to +start capturing, will return an appropriate error code. When the +driver captures continuously (as opposed to, for example, still +images) and data is already available the +select() function returns immediately. + + When use of the write() function has +been negotiated the select() function just waits +until the driver is ready for a non-blocking +write() call. + + All drivers implementing the read() or +write() function or streaming I/O must also +support the select() function. + + For more details see the select() +manual page. + + + + + Return Value + + On success, select() returns the number +of descriptors contained in the three returned descriptor sets, which +will be zero if the timeout expired. On error +-1 is returned, and the +errno variable is set appropriately; the sets and +timeout are undefined. Possible error codes +are: + + + + EBADF + + One or more of the file descriptor sets specified a +file descriptor that is not open. + + + + EBUSY + + The driver does not support multiple read or write +streams and the device is already in use. + + + + EFAULT + + The readfds, +writefds, exceptfds or +timeout pointer references an inaccessible memory +area. + + + + EINTR + + The call was interrupted by a signal. + + + + EINVAL + + The nfds argument is less than +zero or greater than FD_SETSIZE. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/func-write.xml b/Documentation/DocBook/media/v4l/func-write.xml new file mode 100644 index 00000000000..2c09c09371c --- /dev/null +++ b/Documentation/DocBook/media/v4l/func-write.xml @@ -0,0 +1,136 @@ + + + V4L2 write() + &manvol; + + + + v4l2-write + Write to a V4L2 device + + + + + #include <unistd.h> + + ssize_t write + int fd + void *buf + size_t count + + + + + + Arguments + + + + fd + + &fd; + + + + buf + + + + + + count + + + + + + + + + Description + + write() writes up to +count bytes to the device referenced by the +file descriptor fd from the buffer starting at +buf. When the hardware outputs are not active +yet, this function enables them. When count is +zero, write() returns +0 without any other effect. + + When the application does not provide more data in time, the +previous video frame, raw VBI image, sliced VPS or WSS data is +displayed again. Sliced Teletext or Closed Caption data is not +repeated, the driver inserts a blank line instead. + + + + Return Value + + On success, the number of bytes written are returned. Zero +indicates nothing was written. On error, -1 +is returned, and the errno variable is set +appropriately. In this case the next write will start at the beginning +of a new frame. Possible error codes are: + + + + EAGAIN + + Non-blocking I/O has been selected using the O_NONBLOCK flag and no +buffer space was available to write the data immediately. + + + + EBADF + + fd is not a valid file +descriptor or is not open for writing. + + + + EBUSY + + The driver does not support multiple write streams and the +device is already in use. + + + + EFAULT + + buf references an inaccessible +memory area. + + + + EINTR + + The call was interrupted by a signal before any +data was written. + + + + EIO + + I/O error. This indicates some hardware problem. + + + + EINVAL + + The write() function is not +supported by this driver, not on this device, or generally not on this +type of device. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml new file mode 100644 index 00000000000..227e7ac45a0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/io.xml @@ -0,0 +1,1265 @@ + Input/Output + + The V4L2 API defines several different methods to read from or +write to a device. All drivers exchanging data with applications must +support at least one of them. + + The classic I/O method using the read() +and write() function is automatically selected +after opening a V4L2 device. When the driver does not support this +method attempts to read or write will fail at any time. + + Other methods must be negotiated. To select the streaming I/O +method with memory mapped or user buffers applications call the +&VIDIOC-REQBUFS; ioctl. The asynchronous I/O method is not defined +yet. + + Video overlay can be considered another I/O method, although +the application does not directly receive the image data. It is +selected by initiating video overlay with the &VIDIOC-S-FMT; ioctl. +For more information see . + + Generally exactly one I/O method, including overlay, is +associated with each file descriptor. The only exceptions are +applications not exchanging data with a driver ("panel applications", +see ) and drivers permitting simultaneous video capturing +and overlay using the same file descriptor, for compatibility with V4L +and earlier versions of V4L2. + + VIDIOC_S_FMT and +VIDIOC_REQBUFS would permit this to some degree, +but for simplicity drivers need not support switching the I/O method +(after first switching away from read/write) other than by closing +and reopening the device. + + The following sections describe the various I/O methods in +more detail. + +
+ Read/Write + + Input and output devices support the +read() and write() function, +respectively, when the V4L2_CAP_READWRITE flag in +the capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. + + Drivers may need the CPU to copy the data, but they may also +support DMA to or from user memory, so this I/O method is not +necessarily less efficient than other methods merely exchanging buffer +pointers. It is considered inferior though because no meta-information +like frame counters or timestamps are passed. This information is +necessary to recognize frame dropping and to synchronize with other +data streams. However this is also the simplest I/O method, requiring +little or no setup to exchange data. It permits command line stunts +like this (the vidctrl tool is +fictitious): + + + +> vidctrl /dev/video --input=0 --format=YUYV --size=352x288 +> dd if=/dev/video of=myimage.422 bs=202752 count=1 + + + + To read from the device applications use the +&func-read; function, to write the &func-write; function. +Drivers must implement one I/O method if they +exchange data with applications, but it need not be this. + It would be desirable if applications could depend on +drivers supporting all I/O interfaces, but as much as the complex +memory mapping I/O can be inadequate for some devices we have no +reason to require this interface, which is most useful for simple +applications capturing still images. + When reading or writing is supported, the driver +must also support the &func-select; and &func-poll; +function. + At the driver level select() and +poll() are the same, and +select() is too important to be optional. + +
+ +
+ Streaming I/O (Memory Mapping) + + Input and output devices support this I/O method when the +V4L2_CAP_STREAMING flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. There are two +streaming methods, to determine if the memory mapping flavor is +supported applications must call the &VIDIOC-REQBUFS; ioctl. + + Streaming is an I/O method where only pointers to buffers +are exchanged between application and driver, the data itself is not +copied. Memory mapping is primarily intended to map buffers in device +memory into the application's address space. Device memory can be for +example the video memory on a graphics card with a video capture +add-on. However, being the most efficient I/O method available for a +long time, many other drivers support streaming as well, allocating +buffers in DMA-able main memory. + + A driver can support many sets of buffers. Each set is +identified by a unique buffer type value. The sets are independent and +each set can hold a different type of data. To access different sets +at the same time different file descriptors must be used. + One could use one file descriptor and set the buffer +type field accordingly when calling &VIDIOC-QBUF; etc., but it makes +the select() function ambiguous. We also like the +clean approach of one file descriptor per logical stream. Video +overlay for example is also a logical stream, although the CPU is not +needed for continuous operation. + + + To allocate device buffers applications call the +&VIDIOC-REQBUFS; ioctl with the desired number of buffers and buffer +type, for example V4L2_BUF_TYPE_VIDEO_CAPTURE. +This ioctl can also be used to change the number of buffers or to free +the allocated memory, provided none of the buffers are still +mapped. + + Before applications can access the buffers they must map +them into their address space with the &func-mmap; function. The +location of the buffers in device memory can be determined with the +&VIDIOC-QUERYBUF; ioctl. In the single-planar API case, the +m.offset and length +returned in a &v4l2-buffer; are passed as sixth and second parameter to the +mmap() function. When using the multi-planar API, +struct &v4l2-buffer; contains an array of &v4l2-plane; structures, each +containing its own m.offset and +length. When using the multi-planar API, every +plane of every buffer has to be mapped separately, so the number of +calls to &func-mmap; should be equal to number of buffers times number of +planes in each buffer. The offset and length values must not be modified. +Remember, the buffers are allocated in physical memory, as opposed to virtual +memory, which can be swapped out to disk. Applications should free the buffers +as soon as possible with the &func-munmap; function. + + + Mapping buffers in the single-planar API + +&v4l2-requestbuffers; reqbuf; +struct { + void *start; + size_t length; +} *buffers; +unsigned int i; + +memset(&reqbuf, 0, sizeof(reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_MMAP; +reqbuf.count = 20; + +if (-1 == ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf)) { + if (errno == EINVAL) + printf("Video capturing or mmap-streaming is not supported\n"); + else + perror("VIDIOC_REQBUFS"); + + exit(EXIT_FAILURE); +} + +/* We want at least five buffers. */ + +if (reqbuf.count < 5) { + /* You may need to free the buffers here. */ + printf("Not enough buffer memory\n"); + exit(EXIT_FAILURE); +} + +buffers = calloc(reqbuf.count, sizeof(*buffers)); +assert(buffers != NULL); + +for (i = 0; i < reqbuf.count; i++) { + &v4l2-buffer; buffer; + + memset(&buffer, 0, sizeof(buffer)); + buffer.type = reqbuf.type; + buffer.memory = V4L2_MEMORY_MMAP; + buffer.index = i; + + if (-1 == ioctl (fd, &VIDIOC-QUERYBUF;, &buffer)) { + perror("VIDIOC_QUERYBUF"); + exit(EXIT_FAILURE); + } + + buffers[i].length = buffer.length; /* remember for munmap() */ + + buffers[i].start = mmap(NULL, buffer.length, + PROT_READ | PROT_WRITE, /* recommended */ + MAP_SHARED, /* recommended */ + fd, buffer.m.offset); + + if (MAP_FAILED == buffers[i].start) { + /* If you do not exit here you should unmap() and free() + the buffers mapped so far. */ + perror("mmap"); + exit(EXIT_FAILURE); + } +} + +/* Cleanup. */ + +for (i = 0; i < reqbuf.count; i++) + munmap(buffers[i].start, buffers[i].length); + + + + + Mapping buffers in the multi-planar API + +&v4l2-requestbuffers; reqbuf; +/* Our current format uses 3 planes per buffer */ +#define FMT_NUM_PLANES = 3; + +struct { + void *start[FMT_NUM_PLANES]; + size_t length[FMT_NUM_PLANES]; +} *buffers; +unsigned int i, j; + +memset(&reqbuf, 0, sizeof(reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE; +reqbuf.memory = V4L2_MEMORY_MMAP; +reqbuf.count = 20; + +if (ioctl(fd, &VIDIOC-REQBUFS;, &reqbuf) < 0) { + if (errno == EINVAL) + printf("Video capturing or mmap-streaming is not supported\n"); + else + perror("VIDIOC_REQBUFS"); + + exit(EXIT_FAILURE); +} + +/* We want at least five buffers. */ + +if (reqbuf.count < 5) { + /* You may need to free the buffers here. */ + printf("Not enough buffer memory\n"); + exit(EXIT_FAILURE); +} + +buffers = calloc(reqbuf.count, sizeof(*buffers)); +assert(buffers != NULL); + +for (i = 0; i < reqbuf.count; i++) { + &v4l2-buffer; buffer; + &v4l2-plane; planes[FMT_NUM_PLANES]; + + memset(&buffer, 0, sizeof(buffer)); + buffer.type = reqbuf.type; + buffer.memory = V4L2_MEMORY_MMAP; + buffer.index = i; + /* length in struct v4l2_buffer in multi-planar API stores the size + * of planes array. */ + buffer.length = FMT_NUM_PLANES; + buffer.m.planes = planes; + + if (ioctl(fd, &VIDIOC-QUERYBUF;, &buffer) < 0) { + perror("VIDIOC_QUERYBUF"); + exit(EXIT_FAILURE); + } + + /* Every plane has to be mapped separately */ + for (j = 0; j < FMT_NUM_PLANES; j++) { + buffers[i].length[j] = buffer.m.planes[j].length; /* remember for munmap() */ + + buffers[i].start[j] = mmap(NULL, buffer.m.planes[j].length, + PROT_READ | PROT_WRITE, /* recommended */ + MAP_SHARED, /* recommended */ + fd, buffer.m.planes[j].m.offset); + + if (MAP_FAILED == buffers[i].start[j]) { + /* If you do not exit here you should unmap() and free() + the buffers and planes mapped so far. */ + perror("mmap"); + exit(EXIT_FAILURE); + } + } +} + +/* Cleanup. */ + +for (i = 0; i < reqbuf.count; i++) + for (j = 0; j < FMT_NUM_PLANES; j++) + munmap(buffers[i].start[j], buffers[i].length[j]); + + + + Conceptually streaming drivers maintain two buffer queues, an incoming +and an outgoing queue. They separate the synchronous capture or output +operation locked to a video clock from the application which is +subject to random disk or network delays and preemption by +other processes, thereby reducing the probability of data loss. +The queues are organized as FIFOs, buffers will be +output in the order enqueued in the incoming FIFO, and were +captured in the order dequeued from the outgoing FIFO. + + The driver may require a minimum number of buffers enqueued +at all times to function, apart of this no limit exists on the number +of buffers applications can enqueue in advance, or dequeue and +process. They can also enqueue in a different order than buffers have +been dequeued, and the driver can fill enqueued +empty buffers in any order. + Random enqueue order permits applications processing +images out of order (such as video codecs) to return buffers earlier, +reducing the probability of data loss. Random fill order allows +drivers to reuse buffers on a LIFO-basis, taking advantage of caches +holding scatter-gather lists and the like. + The index number of a buffer (&v4l2-buffer; +index) plays no role here, it only +identifies the buffer. + + Initially all mapped buffers are in dequeued state, +inaccessible by the driver. For capturing applications it is customary +to first enqueue all mapped buffers, then to start capturing and enter +the read loop. Here the application waits until a filled buffer can be +dequeued, and re-enqueues the buffer when the data is no longer +needed. Output applications fill and enqueue buffers, when enough +buffers are stacked up the output is started with +VIDIOC_STREAMON. In the write loop, when +the application runs out of free buffers, it must wait until an empty +buffer can be dequeued and reused. + + To enqueue and dequeue a buffer applications use the +&VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. The status of a buffer being +mapped, enqueued, full or empty can be determined at any time using the +&VIDIOC-QUERYBUF; ioctl. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +VIDIOC_DQBUF blocks when no buffer is in the +outgoing queue. When the O_NONBLOCK flag was +given to the &func-open; function, VIDIOC_DQBUF +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available. + + To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +VIDIOC_STREAMOFF removes all buffers from both +queues as a side effect. Since there is no notion of doing anything +"now" on a multitasking system, if an application needs to synchronize +with another event it should examine the &v4l2-buffer; +timestamp of captured buffers, or set the +field before enqueuing buffers for output. + + Drivers implementing memory mapping I/O must +support the VIDIOC_REQBUFS, +VIDIOC_QUERYBUF, +VIDIOC_QBUF, VIDIOC_DQBUF, +VIDIOC_STREAMON and +VIDIOC_STREAMOFF ioctl, the +mmap(), munmap(), +select() and poll() +function. + At the driver level select() and +poll() are the same, and +select() is too important to be optional. The +rest should be evident. + + + [capture example] + +
+ +
+ Streaming I/O (User Pointers) + + Input and output devices support this I/O method when the +V4L2_CAP_STREAMING flag in the +capabilities field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. If the particular user +pointer method (not only memory mapping) is supported must be +determined by calling the &VIDIOC-REQBUFS; ioctl. + + This I/O method combines advantages of the read/write and +memory mapping methods. Buffers (planes) are allocated by the application +itself, and can reside for example in virtual or shared memory. Only +pointers to data are exchanged, these pointers and meta-information +are passed in &v4l2-buffer; (or in &v4l2-plane; in the multi-planar API case). +The driver must be switched into user pointer I/O mode by calling the +&VIDIOC-REQBUFS; with the desired buffer type. No buffers (planes) are allocated +beforehand, consequently they are not indexed and cannot be queried like mapped +buffers with the VIDIOC_QUERYBUF ioctl. + + + Initiating streaming I/O with user pointers + + +&v4l2-requestbuffers; reqbuf; + +memset (&reqbuf, 0, sizeof (reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_USERPTR; + +if (ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf) == -1) { + if (errno == EINVAL) + printf ("Video capturing or user pointer streaming is not supported\n"); + else + perror ("VIDIOC_REQBUFS"); + + exit (EXIT_FAILURE); +} + + + + Buffer (plane) addresses and sizes are passed on the fly with the +&VIDIOC-QBUF; ioctl. Although buffers are commonly cycled, +applications can pass different addresses and sizes at each +VIDIOC_QBUF call. If required by the hardware the +driver swaps memory pages within physical memory to create a +continuous area of memory. This happens transparently to the +application in the virtual memory subsystem of the kernel. When buffer +pages have been swapped out to disk they are brought back and finally +locked in physical memory for DMA. + We expect that frequently used buffers are typically not +swapped out. Anyway, the process of swapping, locking or generating +scatter-gather lists may be time consuming. The delay can be masked by +the depth of the incoming buffer queue, and perhaps by maintaining +caches assuming a buffer will be soon enqueued again. On the other +hand, to optimize memory usage drivers can limit the number of buffers +locked in advance and recycle the most recently used buffers first. Of +course, the pages of empty buffers in the incoming queue need not be +saved to disk. Output buffers must be saved on the incoming and +outgoing queue because an application may share them with other +processes. + + + Filled or displayed buffers are dequeued with the +&VIDIOC-DQBUF; ioctl. The driver can unlock the memory pages at any +time between the completion of the DMA and this ioctl. The memory is +also unlocked when &VIDIOC-STREAMOFF; is called, &VIDIOC-REQBUFS;, or +when the device is closed. Applications must take care not to free +buffers without dequeuing. For once, the buffers remain locked until +further, wasting physical memory. Second the driver will not be +notified when the memory is returned to the application's free list +and subsequently reused for other purposes, possibly completing the +requested DMA and overwriting valuable data. + + For capturing applications it is customary to enqueue a +number of empty buffers, to start capturing and enter the read loop. +Here the application waits until a filled buffer can be dequeued, and +re-enqueues the buffer when the data is no longer needed. Output +applications fill and enqueue buffers, when enough buffers are stacked +up output is started. In the write loop, when the application +runs out of free buffers it must wait until an empty buffer can be +dequeued and reused. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +VIDIOC_DQBUF blocks when no buffer is in the +outgoing queue. When the O_NONBLOCK flag was +given to the &func-open; function, VIDIOC_DQBUF +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available. + + To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +VIDIOC_STREAMOFF removes all buffers from both +queues and unlocks all buffers as a side effect. Since there is no +notion of doing anything "now" on a multitasking system, if an +application needs to synchronize with another event it should examine +the &v4l2-buffer; timestamp of captured +buffers, or set the field before enqueuing buffers for output. + + Drivers implementing user pointer I/O must +support the VIDIOC_REQBUFS, +VIDIOC_QBUF, VIDIOC_DQBUF, +VIDIOC_STREAMON and +VIDIOC_STREAMOFF ioctl, the +select() and poll() function. + At the driver level select() and +poll() are the same, and +select() is too important to be optional. The +rest should be evident. + +
+ +
+ Asynchronous I/O + + This method is not defined yet. +
+ +
+ Buffers + + A buffer contains data exchanged by application and +driver using one of the Streaming I/O methods. In the multi-planar API, the +data is held in planes, while the buffer structure acts as a container +for the planes. Only pointers to buffers (planes) are exchanged, the data +itself is not copied. These pointers, together with meta-information like +timestamps or field parity, are stored in a struct +v4l2_buffer, argument to +the &VIDIOC-QUERYBUF;, &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. +In the multi-planar API, some plane-specific members of struct +v4l2_buffer, such as pointers and sizes for each +plane, are stored in struct v4l2_plane instead. +In that case, struct v4l2_buffer contains an array of +plane structures. + + Nominally timestamps refer to the first data byte transmitted. +In practice however the wide range of hardware covered by the V4L2 API +limits timestamp accuracy. Often an interrupt routine will +sample the system clock shortly after the field or frame was stored +completely in memory. So applications must expect a constant +difference up to one field or frame period plus a small (few scan +lines) random error. The delay and error can be much +larger due to compression or transmission over an external bus when +the frames are not properly stamped by the sender. This is frequently +the case with USB cameras. Here timestamps refer to the instant the +field or frame was received by the driver, not the capture time. These +devices identify by not enumerating any video standards, see . + + Similar limitations apply to output timestamps. Typically +the video hardware locks to a clock controlling the video timing, the +horizontal and vertical synchronization pulses. At some point in the +line sequence, possibly the vertical blanking, an interrupt routine +samples the system clock, compares against the timestamp and programs +the hardware to repeat the previous field or frame, or to display the +buffer contents. + + Apart of limitations of the video device and natural +inaccuracies of all clocks, it should be noted system time itself is +not perfectly stable. It can be affected by power saving cycles, +warped to insert leap seconds, or even turned back or forth by the +system administrator affecting long term measurements. + Since no other Linux multimedia +API supports unadjusted time it would be foolish to introduce here. We +must use a universally supported clock to synchronize different media, +hence time of day. + + + + struct <structname>v4l2_buffer</structname> + + &cs-ustr; + + + __u32 + index + + Number of the buffer, set by the application. This +field is only used for memory mapping I/O +and can range from zero to the number of buffers allocated +with the &VIDIOC-REQBUFS; ioctl (&v4l2-requestbuffers; count) minus one. + + + &v4l2-buf-type; + type + + Type of the buffer, same as &v4l2-format; +type or &v4l2-requestbuffers; +type, set by the application. + + + __u32 + bytesused + + The number of bytes occupied by the data in the +buffer. It depends on the negotiated data format and may change with +each buffer for compressed variable size data like JPEG images. +Drivers must set this field when type +refers to an input stream, applications when an output stream. + + + __u32 + flags + + Flags set by the application or driver, see . + + + &v4l2-field; + field + + Indicates the field order of the image in the +buffer, see . This field is not used when +the buffer contains VBI data. Drivers must set it when +type refers to an input stream, +applications when an output stream. + + + struct timeval + timestamp + + For input streams this is the +system time (as returned by the gettimeofday() +function) when the first data byte was captured. For output streams +the data will not be displayed before this time, secondary to the +nominal frame rate determined by the current video standard in +enqueued order. Applications can for example zero this field to +display frames as soon as possible. The driver stores the time at +which the first data byte was actually sent out in the +timestamp field. This permits +applications to monitor the drift between the video and system +clock. + + + &v4l2-timecode; + timecode + + When type is +V4L2_BUF_TYPE_VIDEO_CAPTURE and the +V4L2_BUF_FLAG_TIMECODE flag is set in +flags, this structure contains a frame +timecode. In V4L2_FIELD_ALTERNATE +mode the top and bottom field contain the same timecode. +Timecodes are intended to help video editing and are typically recorded on +video tapes, but also embedded in compressed formats like MPEG. This +field is independent of the timestamp and +sequence fields. + + + __u32 + sequence + + Set by the driver, counting the frames in the +sequence. + + + In V4L2_FIELD_ALTERNATE mode the top and +bottom field have the same sequence number. The count starts at zero +and includes dropped or repeated frames. A dropped frame was received +by an input device but could not be stored due to lack of free buffer +space. A repeated frame was displayed again by an output device +because the application did not pass new data in +time.Note this may count the frames received +e.g. over USB, without taking into account the frames dropped by the +remote hardware due to limited compression throughput or bus +bandwidth. These devices identify by not enumerating any video +standards, see . + + + &v4l2-memory; + memory + + This field must be set by applications and/or drivers +in accordance with the selected I/O method. + + + union + m + + + + __u32 + offset + For the single-planar API and when +memory is V4L2_MEMORY_MMAP this +is the offset of the buffer from the start of the device memory. The value is +returned by the driver and apart of serving as parameter to the &func-mmap; +function not useful for applications. See for details + + + + + unsigned long + userptr + For the single-planar API and when +memory is V4L2_MEMORY_USERPTR +this is a pointer to the buffer (casted to unsigned long type) in virtual +memory, set by the application. See for details. + + + + + struct v4l2_plane + *planes + When using the multi-planar API, contains a userspace pointer + to an array of &v4l2-plane;. The size of the array should be put + in the length field of this + v4l2_buffer structure. + + + __u32 + length + + Size of the buffer (not the payload) in bytes for the + single-planar API. For the multi-planar API should contain the + number of elements in the planes array. + + + + __u32 + input + + Some video capture drivers support rapid and +synchronous video input changes, a function useful for example in +video surveillance applications. For this purpose applications set the +V4L2_BUF_FLAG_INPUT flag, and this field to the +number of a video input as in &v4l2-input; field +index. + + + __u32 + reserved + + A place holder for future extensions and custom +(driver defined) buffer types +V4L2_BUF_TYPE_PRIVATE and higher. Applications +should set this to 0. + + + +
+ + + struct <structname>v4l2_plane</structname> + + &cs-ustr; + + + __u32 + bytesused + + The number of bytes occupied by data in the plane + (its payload). + + + __u32 + length + + Size in bytes of the plane (not its payload). + + + union + m + + + + + + __u32 + mem_offset + When the memory type in the containing &v4l2-buffer; is + V4L2_MEMORY_MMAP, this is the value that + should be passed to &func-mmap;, similar to the + offset field in &v4l2-buffer;. + + + + __unsigned long + userptr + When the memory type in the containing &v4l2-buffer; is + V4L2_MEMORY_USERPTR, this is a userspace + pointer to the memory allocated for this plane by an application. + + + + __u32 + data_offset + + Offset in bytes to video data in the plane, if applicable. + + + + __u32 + reserved[11] + + Reserved for future use. Should be zeroed by an + application. + + + +
+ + + enum v4l2_buf_type + + &cs-def; + + + V4L2_BUF_TYPE_VIDEO_CAPTURE + 1 + Buffer of a single-planar video capture stream, see . + + + V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE + + 9 + Buffer of a multi-planar video capture stream, see . + + + V4L2_BUF_TYPE_VIDEO_OUTPUT + 2 + Buffer of a single-planar video output stream, see . + + + V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE + + 10 + Buffer of a multi-planar video output stream, see . + + + V4L2_BUF_TYPE_VIDEO_OVERLAY + 3 + Buffer for video overlay, see . + + + V4L2_BUF_TYPE_VBI_CAPTURE + 4 + Buffer of a raw VBI capture stream, see . + + + V4L2_BUF_TYPE_VBI_OUTPUT + 5 + Buffer of a raw VBI output stream, see . + + + V4L2_BUF_TYPE_SLICED_VBI_CAPTURE + 6 + Buffer of a sliced VBI capture stream, see . + + + V4L2_BUF_TYPE_SLICED_VBI_OUTPUT + 7 + Buffer of a sliced VBI output stream, see . + + + V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY + 8 + Buffer for video output overlay (OSD), see . Status: Experimental. + + + V4L2_BUF_TYPE_PRIVATE + 0x80 + This and higher values are reserved for custom +(driver defined) buffer types. + + + +
+ + + Buffer Flags + + &cs-def; + + + V4L2_BUF_FLAG_MAPPED + 0x0001 + The buffer resides in device memory and has been mapped +into the application's address space, see for details. +Drivers set or clear this flag when the +VIDIOC_QUERYBUF, VIDIOC_QBUF or VIDIOC_DQBUF ioctl is called. Set by the driver. + + + V4L2_BUF_FLAG_QUEUED + 0x0002 + Internally drivers maintain two buffer queues, an +incoming and outgoing queue. When this flag is set, the buffer is +currently on the incoming queue. It automatically moves to the +outgoing queue after the buffer has been filled (capture devices) or +displayed (output devices). Drivers set or clear this flag when the +VIDIOC_QUERYBUF ioctl is called. After +(successful) calling the VIDIOC_QBUF ioctl it is +always set and after VIDIOC_DQBUF always +cleared. + + + V4L2_BUF_FLAG_DONE + 0x0004 + When this flag is set, the buffer is currently on +the outgoing queue, ready to be dequeued from the driver. Drivers set +or clear this flag when the VIDIOC_QUERYBUF ioctl +is called. After calling the VIDIOC_QBUF or +VIDIOC_DQBUF it is always cleared. Of course a +buffer cannot be on both queues at the same time, the +V4L2_BUF_FLAG_QUEUED and +V4L2_BUF_FLAG_DONE flag are mutually exclusive. +They can be both cleared however, then the buffer is in "dequeued" +state, in the application domain to say so. + + + V4L2_BUF_FLAG_ERROR + 0x0040 + When this flag is set, the buffer has been dequeued + successfully, although the data might have been corrupted. + This is recoverable, streaming may continue as normal and + the buffer may be reused normally. + Drivers set this flag when the VIDIOC_DQBUF + ioctl is called. + + + V4L2_BUF_FLAG_KEYFRAME + 0x0008 + Drivers set or clear this flag when calling the +VIDIOC_DQBUF ioctl. It may be set by video +capture devices when the buffer contains a compressed image which is a +key frame (or field), &ie; can be decompressed on its own. + + + V4L2_BUF_FLAG_PFRAME + 0x0010 + Similar to V4L2_BUF_FLAG_KEYFRAME +this flags predicted frames or fields which contain only differences to a +previous key frame. + + + V4L2_BUF_FLAG_BFRAME + 0x0020 + Similar to V4L2_BUF_FLAG_PFRAME + this is a bidirectional predicted frame or field. [ooc tbd] + + + V4L2_BUF_FLAG_TIMECODE + 0x0100 + The timecode field is valid. +Drivers set or clear this flag when the VIDIOC_DQBUF +ioctl is called. + + + V4L2_BUF_FLAG_INPUT + 0x0200 + The input field is valid. +Applications set or clear this flag before calling the +VIDIOC_QBUF ioctl. + + + +
+ + + enum v4l2_memory + + &cs-def; + + + V4L2_MEMORY_MMAP + 1 + The buffer is used for memory +mapping I/O. + + + V4L2_MEMORY_USERPTR + 2 + The buffer is used for user +pointer I/O. + + + V4L2_MEMORY_OVERLAY + 3 + [to do] + + + +
+ +
+ Timecodes + + The v4l2_timecode structure is +designed to hold a or similar timecode. +(struct timeval timestamps are stored in +&v4l2-buffer; field timestamp.) + + + struct <structname>v4l2_timecode</structname> + + &cs-str; + + + __u32 + type + Frame rate the timecodes are based on, see . + + + __u32 + flags + Timecode flags, see . + + + __u8 + frames + Frame count, 0 ... 23/24/29/49/59, depending on the + type of timecode. + + + __u8 + seconds + Seconds count, 0 ... 59. This is a binary, not BCD number. + + + __u8 + minutes + Minutes count, 0 ... 59. This is a binary, not BCD number. + + + __u8 + hours + Hours count, 0 ... 29. This is a binary, not BCD number. + + + __u8 + userbits[4] + The "user group" bits from the timecode. + + + +
+ + + Timecode Types + + &cs-def; + + + V4L2_TC_TYPE_24FPS + 1 + 24 frames per second, i. e. film. + + + V4L2_TC_TYPE_25FPS + 2 + 25 frames per second, &ie; PAL or SECAM video. + + + V4L2_TC_TYPE_30FPS + 3 + 30 frames per second, &ie; NTSC video. + + + V4L2_TC_TYPE_50FPS + 4 + + + + V4L2_TC_TYPE_60FPS + 5 + + + + +
+ + + Timecode Flags + + &cs-def; + + + V4L2_TC_FLAG_DROPFRAME + 0x0001 + Indicates "drop frame" semantics for counting frames +in 29.97 fps material. When set, frame numbers 0 and 1 at the start of +each minute, except minutes 0, 10, 20, 30, 40, 50 are omitted from the +count. + + + V4L2_TC_FLAG_COLORFRAME + 0x0002 + The "color frame" flag. + + + V4L2_TC_USERBITS_field + 0x000C + Field mask for the "binary group flags". + + + V4L2_TC_USERBITS_USERDEFINED + 0x0000 + Unspecified format. + + + V4L2_TC_USERBITS_8BITCHARS + 0x0008 + 8-bit ISO characters. + + + +
+
+
+ +
+ Field Order + + We have to distinguish between progressive and interlaced +video. Progressive video transmits all lines of a video image +sequentially. Interlaced video divides an image into two fields, +containing only the odd and even lines of the image, respectively. +Alternating the so called odd and even field are transmitted, and due +to a small delay between fields a cathode ray TV displays the lines +interleaved, yielding the original frame. This curious technique was +invented because at refresh rates similar to film the image would +fade out too quickly. Transmitting fields reduces the flicker without +the necessity of doubling the frame rate and with it the bandwidth +required for each channel. + + It is important to understand a video camera does not expose +one frame at a time, merely transmitting the frames separated into +fields. The fields are in fact captured at two different instances in +time. An object on screen may well move between one field and the +next. For applications analysing motion it is of paramount importance +to recognize which field of a frame is older, the temporal +order. + + When the driver provides or accepts images field by field +rather than interleaved, it is also important applications understand +how the fields combine to frames. We distinguish between top (aka odd) and +bottom (aka even) fields, the spatial order: The first line +of the top field is the first line of an interlaced frame, the first +line of the bottom field is the second line of that frame. + + However because fields were captured one after the other, +arguing whether a frame commences with the top or bottom field is +pointless. Any two successive top and bottom, or bottom and top fields +yield a valid frame. Only when the source was progressive to begin +with, ⪚ when transferring film to video, two fields may come from +the same frame, creating a natural order. + + Counter to intuition the top field is not necessarily the +older field. Whether the older field contains the top or bottom lines +is a convention determined by the video standard. Hence the +distinction between temporal and spatial order of fields. The diagrams +below should make this clearer. + + All video capture and output devices must report the current +field order. Some drivers may permit the selection of a different +order, to this end applications initialize the +field field of &v4l2-pix-format; before +calling the &VIDIOC-S-FMT; ioctl. If this is not desired it should +have the value V4L2_FIELD_ANY (0). + + + enum v4l2_field + + &cs-def; + + + V4L2_FIELD_ANY + 0 + Applications request this field order when any +one of the V4L2_FIELD_NONE, +V4L2_FIELD_TOP, +V4L2_FIELD_BOTTOM, or +V4L2_FIELD_INTERLACED formats is acceptable. +Drivers choose depending on hardware capabilities or e. g. the +requested image size, and return the actual field order. &v4l2-buffer; +field can never be +V4L2_FIELD_ANY. + + + V4L2_FIELD_NONE + 1 + Images are in progressive format, not interlaced. +The driver may also indicate this order when it cannot distinguish +between V4L2_FIELD_TOP and +V4L2_FIELD_BOTTOM. + + + V4L2_FIELD_TOP + 2 + Images consist of the top (aka odd) field only. + + + V4L2_FIELD_BOTTOM + 3 + Images consist of the bottom (aka even) field only. +Applications may wish to prevent a device from capturing interlaced +images because they will have "comb" or "feathering" artefacts around +moving objects. + + + V4L2_FIELD_INTERLACED + 4 + Images contain both fields, interleaved line by +line. The temporal order of the fields (whether the top or bottom +field is first transmitted) depends on the current video standard. +M/NTSC transmits the bottom field first, all other standards the top +field first. + + + V4L2_FIELD_SEQ_TB + 5 + Images contain both fields, the top field lines +are stored first in memory, immediately followed by the bottom field +lines. Fields are always stored in temporal order, the older one first +in memory. Image sizes refer to the frame, not fields. + + + V4L2_FIELD_SEQ_BT + 6 + Images contain both fields, the bottom field +lines are stored first in memory, immediately followed by the top +field lines. Fields are always stored in temporal order, the older one +first in memory. Image sizes refer to the frame, not fields. + + + V4L2_FIELD_ALTERNATE + 7 + The two fields of a frame are passed in separate +buffers, in temporal order, &ie; the older one first. To indicate the field +parity (whether the current field is a top or bottom field) the driver +or application, depending on data direction, must set &v4l2-buffer; +field to +V4L2_FIELD_TOP or +V4L2_FIELD_BOTTOM. Any two successive fields pair +to build a frame. If fields are successive, without any dropped fields +between them (fields can drop individually), can be determined from +the &v4l2-buffer; sequence field. Image +sizes refer to the frame, not fields. This format cannot be selected +when using the read/write I/O method. + + + V4L2_FIELD_INTERLACED_TB + 8 + Images contain both fields, interleaved line by +line, top field first. The top field is transmitted first. + + + V4L2_FIELD_INTERLACED_BT + 9 + Images contain both fields, interleaved line by +line, top field first. The bottom field is transmitted first. + + + +
+ +
+ Field Order, Top Field First Transmitted + + + + + + + + +
+ +
+ Field Order, Bottom Field First Transmitted + + + + + + + + +
+
+ + diff --git a/Documentation/DocBook/media/v4l/keytable.c.xml b/Documentation/DocBook/media/v4l/keytable.c.xml new file mode 100644 index 00000000000..d53254a3be1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/keytable.c.xml @@ -0,0 +1,172 @@ + +/* keytable.c - This program allows checking/replacing keys at IR + + Copyright (C) 2006-2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/input.h> +#include <sys/ioctl.h> + +#include "parse.h" + +void prtcode (int *codes) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (p->value == (unsigned)codes[1]) { + printf("scancode 0x%04x = %s (0x%02x)\n", codes[0], p->name, codes[1]); + return; + } + } + + if (isprint (codes[1])) + printf("scancode %d = '%c' (0x%02x)\n", codes[0], codes[1], codes[1]); + else + printf("scancode %d = 0x%02x\n", codes[0], codes[1]); +} + +int parse_code(char *string) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (!strcasecmp(p->name, string)) { + return p->value; + } + } + return -1; +} + +int main (int argc, char *argv[]) +{ + int fd; + unsigned int i, j; + int codes[2]; + + if (argc<2 || argc>4) { + printf ("usage: %s <device> to get table; or\n" + " %s <device> <scancode> <keycode>\n" + " %s <device> <keycode_file>\n",*argv,*argv,*argv); + return -1; + } + + if ((fd = open(argv[1], O_RDONLY)) < 0) { + perror("Couldn't open input device"); + return(-1); + } + + if (argc==4) { + int value; + + value=parse_code(argv[3]); + + if (value==-1) { + value = strtol(argv[3], NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(argv[2], NULL, 0); + codes [1] = (unsigned) value; + + if(ioctl(fd, EVIOCSKEYCODE, codes)) + perror ("EVIOCSKEYCODE"); + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + return 0; + } + + if (argc==3) { + FILE *fin; + int value; + char *scancode, *keycode, s[2048]; + + fin=fopen(argv[2],"r"); + if (fin==NULL) { + perror ("opening keycode file"); + return -1; + } + + /* Clears old table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + codes[1] = KEY_RESERVED; + ioctl(fd, EVIOCSKEYCODE, codes); + } + } + + while (fgets(s,sizeof(s),fin)) { + scancode=strtok(s,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + if (!strcasecmp(scancode, "scancode")) { + scancode = strtok(NULL,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + } + + keycode=strtok(NULL,"\n\t =:("); + if (!keycode) { + perror ("parsing input file keycode"); + return -1; + } + + // printf ("parsing %s=%s:", scancode, keycode); + value=parse_code(keycode); + // printf ("\tvalue=%d\n",value); + + if (value==-1) { + value = strtol(keycode, NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(scancode, NULL, 0); + codes [1] = (unsigned) value; + + // printf("\t%04x=%04x\n",codes[0], codes[1]); + if(ioctl(fd, EVIOCSKEYCODE, codes)) { + fprintf(stderr, "Setting scancode 0x%04x with 0x%04x via ",codes[0], codes[1]); + perror ("EVIOCSKEYCODE"); + } + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + } + return 0; + } + + /* Get scancode table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + if (!ioctl(fd, EVIOCGKEYCODE, codes) && codes[1] != KEY_RESERVED) + prtcode(codes); + } + } + return 0; +} + + diff --git a/Documentation/DocBook/media/v4l/libv4l.xml b/Documentation/DocBook/media/v4l/libv4l.xml new file mode 100644 index 00000000000..3cb10ec5192 --- /dev/null +++ b/Documentation/DocBook/media/v4l/libv4l.xml @@ -0,0 +1,167 @@ +Libv4l Userspace Library +
+ Introduction + + libv4l is a collection of libraries which adds a thin abstraction +layer on top of video4linux2 devices. The purpose of this (thin) layer +is to make it easy for application writers to support a wide variety of +devices without having to write separate code for different devices in the +same class. +An example of using libv4l is provided by +v4l2grab. + + + libv4l consists of 3 different libraries: +
+ libv4lconvert + + libv4lconvert is a library that converts several +different pixelformats found in V4L2 drivers into a few common RGB and +YUY formats. + It currently accepts the following V4L2 driver formats: +V4L2_PIX_FMT_BGR24, +V4L2_PIX_FMT_HM12, +V4L2_PIX_FMT_JPEG, +V4L2_PIX_FMT_MJPEG, +V4L2_PIX_FMT_MR97310A, +V4L2_PIX_FMT_OV511, +V4L2_PIX_FMT_OV518, +V4L2_PIX_FMT_PAC207, +V4L2_PIX_FMT_PJPG, +V4L2_PIX_FMT_RGB24, +V4L2_PIX_FMT_SBGGR8, +V4L2_PIX_FMT_SGBRG8, +V4L2_PIX_FMT_SGRBG8, +V4L2_PIX_FMT_SN9C10X, +V4L2_PIX_FMT_SN9C20X_I420, +V4L2_PIX_FMT_SPCA501, +V4L2_PIX_FMT_SPCA505, +V4L2_PIX_FMT_SPCA508, +V4L2_PIX_FMT_SPCA561, +V4L2_PIX_FMT_SQ905C, +V4L2_PIX_FMT_SRGGB8, +V4L2_PIX_FMT_UYVY, +V4L2_PIX_FMT_YUV420, +V4L2_PIX_FMT_YUYV, +V4L2_PIX_FMT_YVU420, +and V4L2_PIX_FMT_YVYU. + + Later on libv4lconvert was expanded to also be able to do +various video processing functions to improve webcam video quality. +The video processing is split in to 2 parts: libv4lconvert/control and +libv4lconvert/processing. + + The control part is used to offer video controls which can +be used to control the video processing functions made available by + libv4lconvert/processing. These controls are stored application wide +(until reboot) by using a persistent shared memory object. + + libv4lconvert/processing offers the actual video +processing functionality. +
+
+ libv4l1 + This library offers functions that can be used to quickly +make v4l1 applications work with v4l2 devices. These functions work exactly +like the normal open/close/etc, except that libv4l1 does full emulation of +the v4l1 api on top of v4l2 drivers, in case of v4l1 drivers it +will just pass calls through. + Since those functions are emulations of the old V4L1 API, +it shouldn't be used for new applications. +
+
+ libv4l2 + This library should be used for all modern V4L2 +applications. + It provides handles to call V4L2 open/ioctl/close/poll +methods. Instead of just providing the raw output of the device, it enhances +the calls in the sense that it will use libv4lconvert to provide more video +formats and to enhance the image quality. + In most cases, libv4l2 just passes the calls directly +through to the v4l2 driver, intercepting the calls to +VIDIOC_TRY_FMT, +VIDIOC_G_FMT +VIDIOC_S_FMT +VIDIOC_ENUM_FRAMESIZES +and VIDIOC_ENUM_FRAMEINTERVALS +in order to emulate the formats +V4L2_PIX_FMT_BGR24, +V4L2_PIX_FMT_RGB24, +V4L2_PIX_FMT_YUV420, +and V4L2_PIX_FMT_YVU420, +if they aren't available in the driver. +VIDIOC_ENUM_FMT +keeps enumerating the hardware supported formats, plus the emulated formats +offered by libv4l at the end. + +
+ Libv4l device control functions + The common file operation methods are provided by +libv4l. + Those functions operate just like glibc +open/close/dup/ioctl/read/mmap/munmap: + + int v4l2_open(const char *file, int oflag, +...) - +operates like the standard open() function. + + int v4l2_close(int fd) - +operates like the standard close() function. + + int v4l2_dup(int fd) - +operates like the standard dup() function, duplicating a file handler. + + int v4l2_ioctl (int fd, unsigned long int request, ...) - +operates like the standard ioctl() function. + + int v4l2_read (int fd, void* buffer, size_t n) - +operates like the standard read() function. + + void v4l2_mmap(void *start, size_t length, int prot, int flags, int fd, int64_t offset); - +operates like the standard mmap() function. + + int v4l2_munmap(void *_start, size_t length); - +operates like the standard munmap() function. + + + Those functions provide additional control: + + int v4l2_fd_open(int fd, int v4l2_flags) - +opens an already opened fd for further use through v4l2lib and possibly +modify libv4l2's default behavior through the v4l2_flags argument. +Currently, v4l2_flags can be V4L2_DISABLE_CONVERSION, +to disable format conversion. + + int v4l2_set_control(int fd, int cid, int value) - +This function takes a value of 0 - 65535, and then scales that range to +the actual range of the given v4l control id, and then if the cid exists +and is not locked sets the cid to the scaled value. + + int v4l2_get_control(int fd, int cid) - +This function returns a value of 0 - 65535, scaled to from the actual range +of the given v4l control id. when the cid does not exist, could not be +accessed for some reason, or some error occurred 0 is returned. + + +
+
+
+ + v4l1compat.so wrapper library + + This library intercepts calls to +open/close/ioctl/mmap/mmunmap operations and redirects them to the libv4l +counterparts, by using LD_PRELOAD=/usr/lib/v4l1compat.so. It also +emulates V4L1 calls via V4L2 API. + It allows usage of binary legacy applications that +still don't use libv4l. +
+ +
+ diff --git a/Documentation/DocBook/media/v4l/lirc_device_interface.xml b/Documentation/DocBook/media/v4l/lirc_device_interface.xml new file mode 100644 index 00000000000..0e0453f39e7 --- /dev/null +++ b/Documentation/DocBook/media/v4l/lirc_device_interface.xml @@ -0,0 +1,251 @@ +
+LIRC Device Interface + + +
+Introduction + +The LIRC device interface is a bi-directional interface for +transporting raw IR data between userspace and kernelspace. Fundamentally, +it is just a chardev (/dev/lircX, for X = 0, 1, 2, ...), with a number +of standard struct file_operations defined on it. With respect to +transporting raw IR data to and fro, the essential fops are read, write +and ioctl. + +Example dmesg output upon a driver registering w/LIRC: +
+ $ dmesg |grep lirc_dev + lirc_dev: IR Remote Control driver registered, major 248 + rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0 +
+ +What you should see for a chardev: +
+ $ ls -l /dev/lirc* + crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0 +
+
+ +
+LIRC read fop + +The lircd userspace daemon reads raw IR data from the LIRC chardev. The +exact format of the data depends on what modes a driver supports, and what +mode has been selected. lircd obtains supported modes and sets the active mode +via the ioctl interface, detailed at . The generally +preferred mode is LIRC_MODE_MODE2, in which packets containing an int value +describing an IR signal are read from the chardev. + +See also http://www.lirc.org/html/technical.html for more info. +
+ +
+LIRC write fop + +The data written to the chardev is a pulse/space sequence of integer +values. Pulses and spaces are only marked implicitly by their position. The +data must start and end with a pulse, therefore, the data must always include +an uneven number of samples. The write function must block until the data has +been transmitted by the hardware. +
+ +
+LIRC ioctl fop + +The LIRC device's ioctl definition is bound by the ioctl function +definition of struct file_operations, leaving us with an unsigned int +for the ioctl command and an unsigned long for the arg. For the purposes +of ioctl portability across 32-bit and 64-bit, these values are capped +to their 32-bit sizes. + +The following ioctls can be used to change specific hardware settings. +In general each driver should have a default set of settings. The driver +implementation is expected to re-apply the default settings when the device +is closed by user-space, so that every application opening the device can rely +on working with the default settings initially. + + + + LIRC_GET_FEATURES + + Obviously, get the underlying hardware device's features. If a driver + does not announce support of certain features, calling of the corresponding + ioctls is undefined. + + + + LIRC_GET_SEND_MODE + + Get supported transmit mode. Only LIRC_MODE_PULSE is supported by lircd. + + + + LIRC_GET_REC_MODE + + Get supported receive modes. Only LIRC_MODE_MODE2 and LIRC_MODE_LIRCCODE + are supported by lircd. + + + + LIRC_GET_SEND_CARRIER + + Get carrier frequency (in Hz) currently used for transmit. + + + + LIRC_GET_REC_CARRIER + + Get carrier frequency (in Hz) currently used for IR reception. + + + + LIRC_{G,S}ET_{SEND,REC}_DUTY_CYCLE + + Get/set the duty cycle (from 0 to 100) of the carrier signal. Currently, + no special meaning is defined for 0 or 100, but this could be used to switch + off carrier generation in the future, so these values should be reserved. + + + + LIRC_GET_REC_RESOLUTION + + Some receiver have maximum resolution which is defined by internal + sample rate or data format limitations. E.g. it's common that signals can + only be reported in 50 microsecond steps. This integer value is used by + lircd to automatically adjust the aeps tolerance value in the lircd + config file. + + + + LIRC_GET_M{IN,AX}_TIMEOUT + + Some devices have internal timers that can be used to detect when + there's no IR activity for a long time. This can help lircd in detecting + that a IR signal is finished and can speed up the decoding process. + Returns an integer value with the minimum/maximum timeout that can be + set. Some devices have a fixed timeout, in that case both ioctls will + return the same value even though the timeout cannot be changed. + + + + LIRC_GET_M{IN,AX}_FILTER_{PULSE,SPACE} + + Some devices are able to filter out spikes in the incoming signal + using given filter rules. These ioctls return the hardware capabilities + that describe the bounds of the possible filters. Filter settings depend + on the IR protocols that are expected. lircd derives the settings from + all protocols definitions found in its config file. + + + + LIRC_GET_LENGTH + + Retrieves the code length in bits (only for LIRC_MODE_LIRCCODE). + Reads on the device must be done in blocks matching the bit count. + The bit could should be rounded up so that it matches full bytes. + + + + LIRC_SET_{SEND,REC}_MODE + + Set send/receive mode. Largely obsolete for send, as only + LIRC_MODE_PULSE is supported. + + + + LIRC_SET_{SEND,REC}_CARRIER + + Set send/receive carrier (in Hz). + + + + LIRC_SET_TRANSMITTER_MASK + + This enables the given set of transmitters. The first transmitter + is encoded by the least significant bit, etc. When an invalid bit mask + is given, i.e. a bit is set, even though the device does not have so many + transitters, then this ioctl returns the number of available transitters + and does nothing otherwise. + + + + LIRC_SET_REC_TIMEOUT + + Sets the integer value for IR inactivity timeout (cf. + LIRC_GET_MIN_TIMEOUT and LIRC_GET_MAX_TIMEOUT). A value of 0 (if + supported by the hardware) disables all hardware timeouts and data should + be reported as soon as possible. If the exact value cannot be set, then + the next possible value _greater_ than the given value should be set. + + + + LIRC_SET_REC_TIMEOUT_REPORTS + + Enable (1) or disable (0) timeout reports in LIRC_MODE_MODE2. By + default, timeout reports should be turned off. + + + + LIRC_SET_REC_FILTER_{,PULSE,SPACE} + + Pulses/spaces shorter than this are filtered out by hardware. If + filters cannot be set independently for pulse/space, the corresponding + ioctls must return an error and LIRC_SET_REC_FILTER shall be used instead. + + + + LIRC_SET_MEASURE_CARRIER_MODE + + Enable (1)/disable (0) measure mode. If enabled, from the next key + press on, the driver will send LIRC_MODE2_FREQUENCY packets. By default + this should be turned off. + + + + LIRC_SET_REC_{DUTY_CYCLE,CARRIER}_RANGE + + To set a range use LIRC_SET_REC_DUTY_CYCLE_RANGE/LIRC_SET_REC_CARRIER_RANGE + with the lower bound first and later LIRC_SET_REC_DUTY_CYCLE/LIRC_SET_REC_CARRIER + with the upper bound. + + + + LIRC_NOTIFY_DECODE + + This ioctl is called by lircd whenever a successful decoding of an + incoming IR signal could be done. This can be used by supporting hardware + to give visual feedback to the user e.g. by flashing a LED. + + + + LIRC_SETUP_{START,END} + + Setting of several driver parameters can be optimized by encapsulating + the according ioctl calls with LIRC_SETUP_START/LIRC_SETUP_END. When a + driver receives a LIRC_SETUP_START ioctl it can choose to not commit + further setting changes to the hardware until a LIRC_SETUP_END is received. + But this is open to the driver implementation and every driver must also + handle parameter changes which are not encapsulated by LIRC_SETUP_START + and LIRC_SETUP_END. Drivers can also choose to ignore these ioctls. + + + + LIRC_SET_WIDEBAND_RECEIVER + + Some receivers are equipped with special wide band receiver which is intended + to be used to learn output of existing remote. + Calling that ioctl with (1) will enable it, and with (0) disable it. + This might be useful of receivers that have otherwise narrow band receiver + that prevents them to be used with some remotes. + Wide band receiver might also be more precise + On the other hand its disadvantage it usually reduced range of reception. + Note: wide band receiver might be implictly enabled if you enable + carrier reports. In that case it will be disabled as soon as you disable + carrier reports. Trying to disable wide band receiver while carrier + reports are active will do nothing. + + + + +
+
diff --git a/Documentation/DocBook/media/v4l/media-controller.xml b/Documentation/DocBook/media/v4l/media-controller.xml new file mode 100644 index 00000000000..873ac3a621f --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-controller.xml @@ -0,0 +1,89 @@ + + + + Laurent + Pinchart +
laurent.pinchart@ideasonboard.com
 + Initial version. + + + + 2010 + Laurent Pinchart + + + + + + 1.0.0 + 2010-11-10 + lp + Initial revision + + + + +Media Controller API + + + Media Controller + +
+ Introduction + Media devices increasingly handle multiple related functions. Many USB + cameras include microphones, video capture hardware can also output video, + or SoC camera interfaces also perform memory-to-memory operations similar to + video codecs. + Independent functions, even when implemented in the same hardware, can + be modelled as separate devices. A USB camera with a microphone will be + presented to userspace applications as V4L2 and ALSA capture devices. The + devices' relationships (when using a webcam, end-users shouldn't have to + manually select the associated USB microphone), while not made available + directly to applications by the drivers, can usually be retrieved from + sysfs. + With more and more advanced SoC devices being introduced, the current + approach will not scale. Device topologies are getting increasingly complex + and can't always be represented by a tree structure. Hardware blocks are + shared between different functions, creating dependencies between seemingly + unrelated devices. + Kernel abstraction APIs such as V4L2 and ALSA provide means for + applications to access hardware parameters. As newer hardware expose an + increasingly high number of those parameters, drivers need to guess what + applications really require based on limited information, thereby + implementing policies that belong to userspace. + The media controller API aims at solving those problems. +
+ +
+ Media device model + Discovering a device internal topology, and configuring it at runtime, + is one of the goals of the media controller API. To achieve this, hardware + devices are modelled as an oriented graph of building blocks called entities + connected through pads. + An entity is a basic media hardware or software building block. It can + correspond to a large variety of logical blocks such as physical hardware + devices (CMOS sensor for instance), logical hardware devices (a building + block in a System-on-Chip image processing pipeline), DMA channels or + physical connectors. + A pad is a connection endpoint through which an entity can interact + with other entities. Data (not restricted to video) produced by an entity + flows from the entity's output to one or more entity inputs. Pads should not + be confused with physical pins at chip boundaries. + A link is a point-to-point oriented connection between two pads, + either on the same entity or on different entities. Data flows from a source + pad to a sink pad. +
+ + + + Function Reference + + &sub-media-func-open; + &sub-media-func-close; + &sub-media-func-ioctl; + + &sub-media-ioc-device-info; + &sub-media-ioc-enum-entities; + &sub-media-ioc-enum-links; + &sub-media-ioc-setup-link; + diff --git a/Documentation/DocBook/media/v4l/media-func-close.xml b/Documentation/DocBook/media/v4l/media-func-close.xml new file mode 100644 index 00000000000..be149c802ae --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-close.xml @@ -0,0 +1,59 @@ + + + media close() + &manvol; + + + + media-close + Close a media device + + + + + #include <unistd.h> + + int close + int fd + + + + + + Arguments + + + + fd + + &fd; + + + + + + + Description + + Closes the media device. Resources associated with the file descriptor + are freed. The device configuration remain unchanged. + + + + Return Value + + close returns 0 on success. On error, -1 is + returned, and errno is set appropriately. Possible error + codes are: + + + + EBADF + + fd is not a valid open file descriptor. + + + + + + diff --git a/Documentation/DocBook/media/v4l/media-func-ioctl.xml b/Documentation/DocBook/media/v4l/media-func-ioctl.xml new file mode 100644 index 00000000000..bda8604de15 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-ioctl.xml @@ -0,0 +1,116 @@ + + + media ioctl() + &manvol; + + + + media-ioctl + Control a media device + + + + + #include <sys/ioctl.h> + + int ioctl + int fd + int request + void *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + Media ioctl request code as defined in the media.h header file, + for example MEDIA_IOC_SETUP_LINK. + + + + argp + + Pointer to a request-specific structure. + + + + + + + Description + The ioctl() function manipulates media device + parameters. The argument fd must be an open file + descriptor. + The ioctl request code specifies the media + function to be called. It has encoded in it whether the argument is an + input, output or read/write parameter, and the size of the argument + argp in bytes. + Macros and structures definitions specifying media ioctl requests and + their parameters are located in the media.h header file. All media ioctl + requests, their respective function and parameters are specified in + . + + + + Return Value + + ioctl() returns 0 on + success. On failure, -1 is returned, and the + errno variable is set appropriately. Generic error codes + are listed below, and request-specific error codes are listed in the + individual requests descriptions. + When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified. + + + + EBADF + + fd is not a valid open file descriptor. + + + + + EFAULT + + argp references an inaccessible memory + area. + + + + EINVAL + + The request or the data pointed to by + argp is not valid. This is a very common error + code, see the individual ioctl requests listed in + for actual causes. + + + + ENOMEM + + Insufficient kernel memory was available to complete the + request. + + + + ENOTTY + + fd is not associated with a character + special device. + + + + + diff --git a/Documentation/DocBook/media/v4l/media-func-open.xml b/Documentation/DocBook/media/v4l/media-func-open.xml new file mode 100644 index 00000000000..f7df034dc9e --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-func-open.xml @@ -0,0 +1,94 @@ + + + media open() + &manvol; + + + + media-open + Open a media device + + + + + #include <fcntl.h> + + int open + const char *device_name + int flags + + + + + + Arguments + + + + device_name + + Device to be opened. + + + + flags + + Open flags. Access mode must be either O_RDONLY + or O_RDWR. Other flags have no effect. + + + + + + Description + To open a media device applications call open() + with the desired device name. The function has no side effects; the device + configuration remain unchanged. + When the device is opened in read-only mode, attemps to modify its + configuration will result in an error, and errno will be + set to EBADF. + + + Return Value + + open returns the new file descriptor on success. + On error, -1 is returned, and errno is set appropriately. + Possible error codes are: + + + + EACCES + + The requested access to the file is not allowed. + + + + EMFILE + + The process already has the maximum number of files open. + + + + + ENFILE + + The system limit on the total number of open files has been + reached. + + + + ENOMEM + + Insufficient kernel memory was available. + + + + ENXIO + + No device corresponding to this device special file exists. + + + + + + diff --git a/Documentation/DocBook/media/v4l/media-ioc-device-info.xml b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml new file mode 100644 index 00000000000..1f3237351bb --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml @@ -0,0 +1,133 @@ + + + ioctl MEDIA_IOC_DEVICE_INFO + &manvol; + + + + MEDIA_IOC_DEVICE_INFO + Query device information + + + + + + int ioctl + int fd + int request + struct media_device_info *argp + + + + + + Arguments + + + + fd + + File descriptor returned by + open(). + + + + request + + MEDIA_IOC_DEVICE_INFO + + + + argp + + + + + + + + + Description + + All media devices must support the MEDIA_IOC_DEVICE_INFO + ioctl. To query device information, applications call the ioctl with a + pointer to a &media-device-info;. The driver fills the structure and returns + the information to the application. + The ioctl never fails. + + + struct <structname>media_device_info</structname> + + &cs-str; + + + char + driver[16] + Name of the driver implementing the media API as a + NUL-terminated ASCII string. The driver version is stored in the + driver_version field. + Driver specific applications can use this information to + verify the driver identity. It is also useful to work around + known bugs, or to identify drivers in error reports. + + + char + model[32] + Device model name as a NUL-terminated UTF-8 string. The + device version is stored in the device_version + field and is not be appended to the model name. + + + char + serial[40] + Serial number as a NUL-terminated ASCII string. + + + char + bus_info[32] + Location of the device in the system as a NUL-terminated + ASCII string. This includes the bus type name (PCI, USB, ...) and a + bus-specific identifier. + + + __u32 + media_version + Media API version, formatted with the + KERNEL_VERSION() macro. + + + __u32 + hw_revision + Hardware device revision in a driver-specific format. + + + __u32 + media_version + Media device driver version, formatted with the + KERNEL_VERSION() macro. Together with the + driver field this identifies a particular + driver. + + + __u32 + reserved[31] + Reserved for future extensions. Drivers and applications must + set this array to zero. + + + +
+ The serial and bus_info + fields can be used to distinguish between multiple instances of otherwise + identical hardware. The serial number takes precedence when provided and can + be assumed to be unique. If the serial number is an empty string, the + bus_info field can be used instead. The + bus_info field is guaranteed to be unique, but + can vary across reboots or device unplug/replug. + + + + Return value + This function doesn't return specific error codes. + + diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml new file mode 100644 index 00000000000..576b68b33f2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-entities.xml @@ -0,0 +1,308 @@ + + + ioctl MEDIA_IOC_ENUM_ENTITIES + &manvol; + + + + MEDIA_IOC_ENUM_ENTITIES + Enumerate entities and their properties + + + + + + int ioctl + int fd + int request + struct media_entity_desc *argp + + + + + + Arguments + + + + fd + + File descriptor returned by + open(). + + + + request + + MEDIA_IOC_ENUM_ENTITIES + + + + argp + + + + + + + + + Description + To query the attributes of an entity, applications set the id field + of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES + ioctl with a pointer to this structure. The driver fills the rest of the + structure or returns an &EINVAL; when the id is invalid. + Entities can be enumerated by or'ing the id with the + MEDIA_ENT_ID_FLAG_NEXT flag. The driver will return + information about the entity with the smallest id strictly larger than the + requested one ('next entity'), or the &EINVAL; if there is none. + Entity IDs can be non-contiguous. Applications must + not try to enumerate entities by calling + MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error. + Two or more entities that share a common non-zero + group_id value are considered as logically + grouped. Groups are used to report + + ALSA, VBI and video nodes that carry the same media + stream + lens and flash controllers associated with a sensor + + + + + struct <structname>media_entity_desc</structname> + + + + + + + + + __u32 + id + + + Entity id, set by the application. When the id is or'ed with + MEDIA_ENT_ID_FLAG_NEXT, the driver clears the + flag and returns the first entity with a larger id. + + + char + name[32] + + + Entity name as an UTF-8 NULL-terminated string. + + + __u32 + type + + + Entity type, see for details. + + + __u32 + revision + + + Entity revision in a driver/hardware specific format. + + + __u32 + flags + + + Entity flags, see for details. + + + __u32 + group_id + + + Entity group ID + + + __u16 + pads + + + Number of pads + + + __u16 + links + + + Total number of outbound links. Inbound links are not counted + in this field. + + + union + + + + struct + v4l + + Valid for V4L sub-devices and nodes only. + + + + + __u32 + major + V4L device node major number. For V4L sub-devices with no + device node, set by the driver to 0. + + + + + __u32 + minor + V4L device node minor number. For V4L sub-devices with no + device node, set by the driver to 0. + + + + struct + fb + + Valid for frame buffer nodes only. + + + + + __u32 + major + Frame buffer device node major number. + + + + + __u32 + minor + Frame buffer device node minor number. + + + + struct + alsa + + Valid for ALSA devices only. + + + + + __u32 + card + ALSA card number + + + + + __u32 + device + ALSA device number + + + + + __u32 + subdevice + ALSA sub-device number + + + + int + dvb + + DVB card number + + + + __u8 + raw[180] + + + + + +
+ + + Media entity types + + + + + + MEDIA_ENT_T_DEVNODE + Unknown device node + + + MEDIA_ENT_T_DEVNODE_V4L + V4L video, radio or vbi device node + + + MEDIA_ENT_T_DEVNODE_FB + Frame buffer device node + + + MEDIA_ENT_T_DEVNODE_ALSA + ALSA card + + + MEDIA_ENT_T_DEVNODE_DVB + DVB card + + + MEDIA_ENT_T_V4L2_SUBDEV + Unknown V4L sub-device + + + MEDIA_ENT_T_V4L2_SUBDEV_SENSOR + Video sensor + + + MEDIA_ENT_T_V4L2_SUBDEV_FLASH + Flash controller + + + MEDIA_ENT_T_V4L2_SUBDEV_LENS + Lens controller + + + +
+ + + Media entity flags + + + + + + MEDIA_ENT_FL_DEFAULT + Default entity for its type. Used to discover the default + audio, VBI and video devices, the default camera sensor, ... + + + +
+ + + + &return-value; + + + + EINVAL + + The &media-entity-desc; id references + a non-existing entity. + + + + + diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml new file mode 100644 index 00000000000..d2fc73ef8d5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml @@ -0,0 +1,207 @@ + + + ioctl MEDIA_IOC_ENUM_LINKS + &manvol; + + + + MEDIA_IOC_ENUM_LINKS + Enumerate all pads and links for a given entity + + + + + + int ioctl + int fd + int request + struct media_links_enum *argp + + + + + + Arguments + + + + fd + + File descriptor returned by + open(). + + + + request + + MEDIA_IOC_ENUM_LINKS + + + + argp + + + + + + + + + Description + + To enumerate pads and/or links for a given entity, applications set + the entity field of a &media-links-enum; structure and initialize the + &media-pad-desc; and &media-link-desc; structure arrays pointed by the + pads and links fields. + They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this + structure. + If the pads field is not NULL, the driver + fills the pads array with information about the + entity's pads. The array must have enough room to store all the entity's + pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES; + ioctl. + If the links field is not NULL, the driver + fills the links array with information about the + entity's outbound links. The array must have enough room to store all the + entity's outbound links. The number of outbound links can be retrieved with + the &MEDIA-IOC-ENUM-ENTITIES; ioctl. + Only forward links that originate at one of the entity's source pads + are returned during the enumeration process. + + + struct <structname>media_links_enum</structname> + + &cs-str; + + + __u32 + entity + Entity id, set by the application. + + + struct &media-pad-desc; + *pads + Pointer to a pads array allocated by the application. Ignored + if NULL. + + + struct &media-link-desc; + *links + Pointer to a links array allocated by the application. Ignored + if NULL. + + + + + + + struct <structname>media_pad_desc</structname> + + &cs-str; + + + __u32 + entity + ID of the entity this pad belongs to. + + + __u16 + index + 0-based pad index. + + + __u32 + flags + Pad flags, see for more details. + + + +
+ + + Media pad flags + + + + + + MEDIA_PAD_FL_SINK + Input pad, relative to the entity. Input pads sink data and + are targets of links. + + + MEDIA_PAD_FL_SOURCE + Output pad, relative to the entity. Output pads source data + and are origins of links. + + + +
+ + + struct <structname>media_links_desc</structname> + + &cs-str; + + + struct &media-pad-desc; + source + Pad at the origin of this link. + + + struct &media-pad-desc; + sink + Pad at the target of this link. + + + __u32 + flags + Link flags, see for more details. + + + + + + + Media link flags + + + + + + MEDIA_LNK_FL_ENABLED + The link is enabled and can be used to transfer media data. + When two or more links target a sink pad, only one of them can be + enabled at a time. + + + MEDIA_LNK_FL_IMMUTABLE + The link enabled state can't be modified at runtime. An + immutable link is always enabled. + + + MEDIA_LNK_FL_DYNAMIC + The link enabled state can be modified during streaming. This + flag is set by drivers and is read-only for applications. + + + + + One and only one of MEDIA_PAD_FL_SINK and + MEDIA_PAD_FL_SOURCE must be set for every pad. + + + + &return-value; + + + + EINVAL + + The &media-links-enum; id references + a non-existing entity. + + + + + diff --git a/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml new file mode 100644 index 00000000000..cec97af4dab --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml @@ -0,0 +1,93 @@ + + + ioctl MEDIA_IOC_SETUP_LINK + &manvol; + + + + MEDIA_IOC_SETUP_LINK + Modify the properties of a link + + + + + + int ioctl + int fd + int request + struct media_link_desc *argp + + + + + + Arguments + + + + fd + + File descriptor returned by + open(). + + + + request + + MEDIA_IOC_SETUP_LINK + + + + argp + + + + + + + + + Description + + To change link properties applications fill a &media-link-desc; with + link identification information (source and sink pad) and the new requested + link flags. They then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to + that structure. + The only configurable property is the ENABLED + link flag to enable/disable a link. Links marked with the + IMMUTABLE link flag can not be enabled or disabled. + + Link configuration has no side effect on other links. If an enabled + link at the sink pad prevents the link from being enabled, the driver + returns with an &EBUSY;. + Only links marked with the DYNAMIC link flag can + be enabled/disabled while streaming media data. Attempting to enable or + disable a streaming non-dynamic link will return an &EBUSY;. + If the specified link can't be found the driver returns with an + &EINVAL;. + + + + &return-value; + + + + EBUSY + + The link properties can't be changed because the link is + currently busy. This can be caused, for instance, by an active media + stream (audio or video) on the link. The ioctl shouldn't be retried if + no other action is performed before to fix the problem. + + + + EINVAL + + The &media-link-desc; references a non-existing link, or the + link is immutable and an attempt to modify its configuration was made. + + + + + + diff --git a/Documentation/DocBook/media/v4l/nv12mt.gif b/Documentation/DocBook/media/v4l/nv12mt.gif new file mode 100644 index 00000000000..ef2d4cf8367 Binary files /dev/null and b/Documentation/DocBook/media/v4l/nv12mt.gif differ diff --git a/Documentation/DocBook/media/v4l/nv12mt_example.gif b/Documentation/DocBook/media/v4l/nv12mt_example.gif new file mode 100644 index 00000000000..df81d68108e Binary files /dev/null and b/Documentation/DocBook/media/v4l/nv12mt_example.gif differ diff --git a/Documentation/DocBook/media/v4l/pipeline.pdf b/Documentation/DocBook/media/v4l/pipeline.pdf new file mode 100644 index 00000000000..ee3e37f04b6 Binary files /dev/null and b/Documentation/DocBook/media/v4l/pipeline.pdf differ diff --git a/Documentation/DocBook/media/v4l/pipeline.png b/Documentation/DocBook/media/v4l/pipeline.png new file mode 100644 index 00000000000..f19b86c2c24 Binary files /dev/null and b/Documentation/DocBook/media/v4l/pipeline.png differ diff --git a/Documentation/DocBook/media/v4l/pixfmt-grey.xml b/Documentation/DocBook/media/v4l/pixfmt-grey.xml new file mode 100644 index 00000000000..3b72bc6b2de --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-grey.xml @@ -0,0 +1,70 @@ + + + V4L2_PIX_FMT_GREY ('GREY') + &manvol; + + + V4L2_PIX_FMT_GREY + Grey-scale image + + + Description + + This is a grey-scale image. It is really a degenerate +Y'CbCr format which simply contains no Cb or Cr data. + + + <constant>V4L2_PIX_FMT_GREY</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-m420.xml b/Documentation/DocBook/media/v4l/pixfmt-m420.xml new file mode 100644 index 00000000000..ce4bc019e5c --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-m420.xml @@ -0,0 +1,147 @@ + + + V4L2_PIX_FMT_M420 ('M420') + &manvol; + + + V4L2_PIX_FMT_M420 + Format with ½ horizontal and vertical chroma + resolution, also known as YUV 4:2:0. Hybrid plane line-interleaved + layout. + + + Description + + M420 is a YUV format with ½ horizontal and vertical chroma + subsampling (YUV 4:2:0). Pixels are organized as interleaved luma and + chroma planes. Two lines of luma data are followed by one line of chroma + data. + The luma plane has one byte per pixel. The chroma plane contains + interleaved CbCr pixels subsampled by ½ in the horizontal and + vertical directions. Each CbCr pair belongs to four pixels. For example, +Cb0/Cr0 belongs to +Y'00, Y'01, +Y'10, Y'11. + + All line lengths are identical: if the Y lines include pad bytes + so do the CbCr lines. + + + <constant>V4L2_PIX_FMT_M420</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Cb00 + Cr00 + Cb01 + Cr01 + + + start + 16: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 20: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 24: + Cb10 + Cr10 + Cb11 + Cr11 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml new file mode 100644 index 00000000000..873f6703518 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml @@ -0,0 +1,151 @@ + + + V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21') + &manvol; + + + V4L2_PIX_FMT_NV12 + V4L2_PIX_FMT_NV21 + Formats with ½ horizontal and vertical +chroma resolution, also known as YUV 4:2:0. One luminance and one +chrominance plane with alternating chroma samples as opposed to +V4L2_PIX_FMT_YVU420 + + + Description + + These are two-plane versions of the YUV 4:2:0 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +V4L2_PIX_FMT_NV12, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width, in bytes, as the Y plane (and of the image), but is half as +tall in pixels. Each CbCr pair belongs to four pixels. For example, +Cb0/Cr0 belongs to +Y'00, Y'01, +Y'10, Y'11. +V4L2_PIX_FMT_NV21 is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte. + + If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows. + + + <constant>V4L2_PIX_FMT_NV12</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cb00 + Cr00 + Cb01 + Cr01 + + + start + 20: + Cb10 + Cr10 + Cb11 + Cr11 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml new file mode 100644 index 00000000000..c9e166d9ded --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12m.xml @@ -0,0 +1,154 @@ + + + V4L2_PIX_FMT_NV12M ('NV12M') + &manvol; + + + V4L2_PIX_FMT_NV12M + Variation of V4L2_PIX_FMT_NV12 with planes + non contiguous in memory. + + + Description + + This is a multi-planar, two-plane version of the YUV 4:2:0 format. +The three components are separated into two sub-images or planes. +V4L2_PIX_FMT_NV12M differs from V4L2_PIX_FMT_NV12 + in that the two planes are non-contiguous in memory, i.e. the chroma +plane do not necessarily immediately follows the luma plane. +The luminance data occupies the first plane. The Y plane has one byte per pixel. +In the second plane there is a chrominance data with alternating chroma samples. +The CbCr plane is the same width, in bytes, as the Y plane (and of the image), +but is half as tall in pixels. Each CbCr pair belongs to four pixels. For example, +Cb0/Cr0 belongs to +Y'00, Y'01, +Y'10, Y'11. + + V4L2_PIX_FMT_NV12M is intended to be +used only in drivers and applications that support the multi-planar API, +described in . + + If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows. + + + <constant>V4L2_PIX_FMT_NV12M</constant> 4 × 4 pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start0 + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start0 + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start0 + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start0 + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + + + + start1 + 0: + Cb00 + Cr00 + Cb01 + Cr01 + + + start1 + 4: + Cb10 + Cr10 + Cb11 + Cr11 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml new file mode 100644 index 00000000000..7a2855a526c --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv12mt.xml @@ -0,0 +1,74 @@ + + + V4L2_PIX_FMT_NV12MT ('TM12') + &manvol; + + + V4L2_PIX_FMT_NV12MT + + Formats with ½ horizontal and vertical +chroma resolution. This format has two planes - one for luminance and one for +chrominance. Chroma samples are interleaved. The difference to +V4L2_PIX_FMT_NV12 is the memory layout. Pixels are +grouped in macroblocks of 64x32 size. The order of macroblocks in memory is +also not standard. + + + + Description + + This is the two-plane versions of the YUV 4:2:0 format where data +is grouped into 64x32 macroblocks. The three components are separated into two +sub-images or planes. The Y plane has one byte per pixel and pixels are grouped +into 64x32 macroblocks. The CbCr plane has the same width, in bytes, as the Y +plane (and the image), but is half as tall in pixels. The chroma plane is also +grouped into 64x32 macroblocks. + Width of the buffer has to be aligned to the multiple of 128, and +height alignment is 32. Every four adjactent buffers - two horizontally and two +vertically are grouped together and are located in memory in Z or flipped Z +order. + Layout of macroblocks in memory is presented in the following +figure. +
+ <constant>V4L2_PIX_FMT_NV12MT</constant> macroblock Z shape +memory layout + + + + + +
+ The requirement that width is multiple of 128 is implemented because, +the Z shape cannot be cut in half horizontally. In case the vertical resolution +of macroblocks is odd then the last row of macroblocks is arranged in a linear +order. + In case of chroma the layout is identical. Cb and Cr samples are +interleaved. Height of the buffer is aligned to 32. + + + Memory layout of macroblocks in <constant>V4L2_PIX_FMT_NV12 +</constant> format pixel image - extreme case + +
+ Example <constant>V4L2_PIX_FMT_NV12MT</constant> memory +layout of macroblocks + + + + + +
+ Memory layout of macroblocks of V4L2_PIX_FMT_NV12MT + format in most extreme case. + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv16.xml b/Documentation/DocBook/media/v4l/pixfmt-nv16.xml new file mode 100644 index 00000000000..26094035fc0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-nv16.xml @@ -0,0 +1,174 @@ + + + V4L2_PIX_FMT_NV16 ('NV16'), V4L2_PIX_FMT_NV61 ('NV61') + &manvol; + + + V4L2_PIX_FMT_NV16 + V4L2_PIX_FMT_NV61 + Formats with ½ horizontal +chroma resolution, also known as YUV 4:2:2. One luminance and one +chrominance plane with alternating chroma samples as opposed to +V4L2_PIX_FMT_YVU420 + + + Description + + These are two-plane versions of the YUV 4:2:2 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +V4L2_PIX_FMT_NV16, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width and height, in bytes, as the Y plane (and of the image). +Each CbCr pair belongs to two pixels. For example, +Cb0/Cr0 belongs to +Y'00, Y'01. +V4L2_PIX_FMT_NV61 is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte. + + If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows. + + + <constant>V4L2_PIX_FMT_NV16</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cb00 + Cr00 + Cb01 + Cr01 + + + start + 20: + Cb10 + Cr10 + Cb11 + Cr11 + + + start + 24: + Cb20 + Cr20 + Cb21 + Cr21 + + + start + 28: + Cb30 + Cr30 + Cb31 + Cr31 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + C + C + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + C + C + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml new file mode 100644 index 00000000000..4db272b8a0d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml @@ -0,0 +1,940 @@ + + + Packed RGB formats + &manvol; + + + Packed RGB formats + Packed RGB formats + + + Description + + These formats are designed to match the pixel formats of +typical PC graphics frame buffers. They occupy 8, 16, 24 or 32 bits +per pixel. These are all packed-pixel formats, meaning all the data +for a pixel lie next to each other in memory. + + When one of these formats is used, drivers shall report the +colorspace V4L2_COLORSPACE_SRGB. + + + Packed RGB Image Formats + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Identifier + Code +   + Byte 0 in memory + Byte 1 + Byte 2 + Byte 3 + + +   +   + Bit + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_PIX_FMT_RGB332 + 'RGB1' + + b1 + b0 + g2 + g1 + g0 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB444 + 'R444' + + g3 + g2 + g1 + g0 + b3 + b2 + b1 + b0 + + a3 + a2 + a1 + a0 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB555 + 'RGBO' + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + a + b4 + b3 + b2 + b1 + b0 + g4 + g3 + + + V4L2_PIX_FMT_RGB565 + 'RGBP' + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + b4 + b3 + b2 + b1 + b0 + g5 + g4 + g3 + + + V4L2_PIX_FMT_RGB555X + 'RGBQ' + + a + b4 + b3 + b2 + b1 + b0 + g4 + g3 + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB565X + 'RGBR' + + b4 + b3 + b2 + b1 + b0 + g5 + g4 + g3 + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_BGR666 + 'BGRH' + + b5 + b4 + b3 + b2 + b1 + b0 + g5 + g4 + + g3 + g2 + g1 + g0 + r5 + r4 + r3 + r2 + + r1 + r0 + + + + + + + + + + + + + + + + + V4L2_PIX_FMT_BGR24 + 'BGR3' + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB24 + 'RGB3' + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_PIX_FMT_BGR32 + 'BGR4' + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + a7 + a6 + a5 + a4 + a3 + a2 + a1 + a0 + + + V4L2_PIX_FMT_RGB32 + 'RGB4' + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + a7 + a6 + a5 + a4 + a3 + a2 + a1 + a0 + + + +
+ + Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +Video Overlay or Video Output Overlay. + + + <constant>V4L2_PIX_FMT_BGR24</constant> 4 × 4 pixel +image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + B00 + G00 + R00 + B01 + G01 + R01 + B02 + G02 + R02 + B03 + G03 + R03 + + + start + 12: + B10 + G10 + R10 + B11 + G11 + R11 + B12 + G12 + R12 + B13 + G13 + R13 + + + start + 24: + B20 + G20 + R20 + B21 + G21 + R21 + B22 + G22 + R22 + B23 + G23 + R23 + + + start + 36: + B30 + G30 + R30 + B31 + G31 + R31 + B32 + G32 + R32 + B33 + G33 + R33 + + + + + + + + + + Drivers may interpret these formats differently. + + + Some RGB formats above are uncommon and were probably +defined in error. Drivers may interpret them as in . + + + Packed RGB Image Formats (corrected) + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Identifier + Code +   + Byte 0 in memory + Byte 1 + Byte 2 + Byte 3 + + +   +   + Bit + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_PIX_FMT_RGB332 + 'RGB1' + + r2 + r1 + r0 + g2 + g1 + g0 + b1 + b0 + + + V4L2_PIX_FMT_RGB444 + 'R444' + + g3 + g2 + g1 + g0 + b3 + b2 + b1 + b0 + + a3 + a2 + a1 + a0 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB555 + 'RGBO' + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + a + r4 + r3 + r2 + r1 + r0 + g4 + g3 + + + V4L2_PIX_FMT_RGB565 + 'RGBP' + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + r4 + r3 + r2 + r1 + r0 + g5 + g4 + g3 + + + V4L2_PIX_FMT_RGB555X + 'RGBQ' + + a + r4 + r3 + r2 + r1 + r0 + g4 + g3 + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + V4L2_PIX_FMT_RGB565X + 'RGBR' + + r4 + r3 + r2 + r1 + r0 + g5 + g4 + g3 + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + V4L2_PIX_FMT_BGR666 + 'BGRH' + + b5 + b4 + b3 + b2 + b1 + b0 + g5 + g4 + + g3 + g2 + g1 + g0 + r5 + r4 + r3 + r2 + + r1 + r0 + + + + + + + + + + + + + + + + + V4L2_PIX_FMT_BGR24 + 'BGR3' + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + V4L2_PIX_FMT_RGB24 + 'RGB3' + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_PIX_FMT_BGR32 + 'BGR4' + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + a7 + a6 + a5 + a4 + a3 + a2 + a1 + a0 + + + V4L2_PIX_FMT_RGB32 + 'RGB4' + + a7 + a6 + a5 + a4 + a3 + a2 + a1 + a0 + + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + +
+ + A test utility to determine which RGB formats a driver +actually supports is available from the LinuxTV v4l-dvb repository. +See &v4l-dvb; for access instructions. + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml b/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml new file mode 100644 index 00000000000..3cab5d0ca75 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-yuv.xml @@ -0,0 +1,244 @@ + + + Packed YUV formats + &manvol; + + + Packed YUV formats + Packed YUV formats + + + Description + + Similar to the packed RGB formats these formats store +the Y, Cb and Cr component of each pixel in one 16 or 32 bit +word. + + + Packed YUV Image Formats + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Identifier + Code +   + Byte 0 in memory + Byte 1 + Byte 2 + Byte 3 + + +   +   + Bit + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 +   + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_PIX_FMT_YUV444 + 'Y444' + + Cb3 + Cb2 + Cb1 + Cb0 + Cr3 + Cr2 + Cr1 + Cr0 + + a3 + a2 + a1 + a0 + Y'3 + Y'2 + Y'1 + Y'0 + + + + V4L2_PIX_FMT_YUV555 + 'YUVO' + + Cb2 + Cb1 + Cb0 + Cr4 + Cr3 + Cr2 + Cr1 + Cr0 + + a + Y'4 + Y'3 + Y'2 + Y'1 + Y'0 + Cb4 + Cb3 + + + + V4L2_PIX_FMT_YUV565 + 'YUVP' + + Cb2 + Cb1 + Cb0 + Cr4 + Cr3 + Cr2 + Cr1 + Cr0 + + Y'4 + Y'3 + Y'2 + Y'1 + Y'0 + Cb5 + Cb4 + Cb3 + + + + V4L2_PIX_FMT_YUV32 + 'YUV4' + + a7 + a6 + a5 + a4 + a3 + a2 + a1 + a0 + + Y'7 + Y'6 + Y'5 + Y'4 + Y'3 + Y'2 + Y'1 + Y'0 + + Cb7 + Cb6 + Cb5 + Cb4 + Cb3 + Cb2 + Cb1 + Cb0 + + Cr7 + Cr6 + Cr5 + Cr4 + Cr3 + Cr2 + Cr1 + Cr0 + + + +
+ + Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +Video Overlay or Video Output Overlay. + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml b/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml new file mode 100644 index 00000000000..519a9efbac1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sbggr16.xml @@ -0,0 +1,91 @@ + + + V4L2_PIX_FMT_SBGGR16 ('BYR2') + &manvol; + + + V4L2_PIX_FMT_SBGGR16 + Bayer RGB format + + + Description + + This format is similar to +V4L2_PIX_FMT_SBGGR8, except each pixel has +a depth of 16 bits. The least significant byte is stored at lower +memory addresses (little-endian). Note the actual sampling precision +may be lower than 16 bits, for example 10 bits per pixel with values +in range 0 to 1023. + + + <constant>V4L2_PIX_FMT_SBGGR16</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + B00low + B00high + G01low + G01high + B02low + B02high + G03low + G03high + + + start + 8: + G10low + G10high + R11low + R11high + G12low + G12high + R13low + R13high + + + start + 16: + B20low + B20high + G21low + G21high + B22low + B22high + G23low + G23high + + + start + 24: + G30low + G30high + R31low + R31high + G32low + G32high + R33low + R33high + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml b/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml new file mode 100644 index 00000000000..5fe84ecc2eb --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sbggr8.xml @@ -0,0 +1,75 @@ + + + V4L2_PIX_FMT_SBGGR8 ('BA81') + &manvol; + + + V4L2_PIX_FMT_SBGGR8 + Bayer RGB format + + + Description + + This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a blue and green value, the second row of a green and +red value. This scheme repeats to the right and down for every two +columns and rows. + + + <constant>V4L2_PIX_FMT_SBGGR8</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + B00 + G01 + B02 + G03 + + + start + 4: + G10 + R11 + G12 + R13 + + + start + 8: + B20 + G21 + B22 + G23 + + + start + 12: + G30 + R31 + G32 + R33 + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml b/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml new file mode 100644 index 00000000000..d67a472b088 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sgbrg8.xml @@ -0,0 +1,75 @@ + + + V4L2_PIX_FMT_SGBRG8 ('GBRG') + &manvol; + + + V4L2_PIX_FMT_SGBRG8 + Bayer RGB format + + + Description + + This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows. + + + <constant>V4L2_PIX_FMT_SGBRG8</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + G00 + B01 + G02 + B03 + + + start + 4: + R10 + G11 + R12 + G13 + + + start + 8: + G20 + B21 + G22 + B23 + + + start + 12: + R30 + G31 + R32 + G33 + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml b/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml new file mode 100644 index 00000000000..0cdf13b8ac1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml @@ -0,0 +1,75 @@ + + + V4L2_PIX_FMT_SGRBG8 ('GRBG') + &manvol; + + + V4L2_PIX_FMT_SGRBG8 + Bayer RGB format + + + Description + + This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows. + + + <constant>V4L2_PIX_FMT_SGRBG8</constant> 4 × +4 pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + G00 + R01 + G02 + R03 + + + start + 4: + R10 + B11 + R12 + B13 + + + start + 8: + G20 + R21 + G22 + R23 + + + start + 12: + R30 + B31 + R32 + B33 + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml new file mode 100644 index 00000000000..7b274092e60 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb10.xml @@ -0,0 +1,90 @@ + + + V4L2_PIX_FMT_SRGGB10 ('RG10'), + V4L2_PIX_FMT_SGRBG10 ('BA10'), + V4L2_PIX_FMT_SGBRG10 ('GB10'), + V4L2_PIX_FMT_SBGGR10 ('BG10'), + + &manvol; + + + V4L2_PIX_FMT_SRGGB10 + V4L2_PIX_FMT_SGRBG10 + V4L2_PIX_FMT_SGBRG10 + V4L2_PIX_FMT_SBGGR10 + 10-bit Bayer formats expanded to 16 bits + + + Description + + The following four pixel formats are raw sRGB / Bayer formats with +10 bits per colour. Each colour component is stored in a 16-bit word, with 6 +unused high bits filled with zeros. Each n-pixel row contains n/2 green samples +and n/2 blue or red samples, with alternating red and blue rows. Bytes are +stored in memory in little endian order. They are conventionally described +as GRGR... BGBG..., RGRG... GBGB..., etc. Below is an example of one of these +formats + + + <constant>V4L2_PIX_FMT_SBGGR10</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte, high 6 bits in high bytes are 0. + + + + + + start + 0: + B00low + B00high + G01low + G01high + B02low + B02high + G03low + G03high + + + start + 8: + G10low + G10high + R11low + R11high + G12low + G12high + R13low + R13high + + + start + 16: + B20low + B20high + G21low + G21high + B22low + B22high + G23low + G23high + + + start + 24: + G30low + G30high + R31low + R31high + G32low + G32high + R33low + R33high + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml new file mode 100644 index 00000000000..9ba4fb690bc --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb12.xml @@ -0,0 +1,90 @@ + + + V4L2_PIX_FMT_SRGGB12 ('RG12'), + V4L2_PIX_FMT_SGRBG12 ('BA12'), + V4L2_PIX_FMT_SGBRG12 ('GB12'), + V4L2_PIX_FMT_SBGGR12 ('BG12'), + + &manvol; + + + V4L2_PIX_FMT_SRGGB12 + V4L2_PIX_FMT_SGRBG12 + V4L2_PIX_FMT_SGBRG12 + V4L2_PIX_FMT_SBGGR12 + 12-bit Bayer formats expanded to 16 bits + + + Description + + The following four pixel formats are raw sRGB / Bayer formats with +12 bits per colour. Each colour component is stored in a 16-bit word, with 6 +unused high bits filled with zeros. Each n-pixel row contains n/2 green samples +and n/2 blue or red samples, with alternating red and blue rows. Bytes are +stored in memory in little endian order. They are conventionally described +as GRGR... BGBG..., RGRG... GBGB..., etc. Below is an example of one of these +formats + + + <constant>V4L2_PIX_FMT_SBGGR12</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte, high 6 bits in high bytes are 0. + + + + + + start + 0: + B00low + B00high + G01low + G01high + B02low + B02high + G03low + G03high + + + start + 8: + G10low + G10high + R11low + R11high + G12low + G12high + R13low + R13high + + + start + 16: + B20low + B20high + G21low + G21high + B22low + B22high + G23low + G23high + + + start + 24: + G30low + G30high + R31low + R31high + G32low + G32high + R33low + R33high + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml b/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml new file mode 100644 index 00000000000..2570e3be3cf --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-srggb8.xml @@ -0,0 +1,67 @@ + + + V4L2_PIX_FMT_SRGGB8 ('RGGB') + &manvol; + + + V4L2_PIX_FMT_SRGGB8 + Bayer RGB format + + + Description + + This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a red and green value, the second row of a green and +blue value. This scheme repeats to the right and down for every two +columns and rows. + + + <constant>V4L2_PIX_FMT_SRGGB8</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + R00 + G01 + R02 + G03 + + + start + 4: + G10 + B11 + G12 + B13 + + + start + 8: + R20 + G21 + R22 + G23 + + + start + 12: + G30 + B31 + G32 + B33 + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml b/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml new file mode 100644 index 00000000000..816c8d467c1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-uyvy.xml @@ -0,0 +1,128 @@ + + + V4L2_PIX_FMT_UYVY ('UYVY') + &manvol; + + + V4L2_PIX_FMT_UYVY + Variation of +V4L2_PIX_FMT_YUYV with different order of samples +in memory + + + Description + + In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component. + + + <constant>V4L2_PIX_FMT_UYVY</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Cb00 + Y'00 + Cr00 + Y'01 + Cb01 + Y'02 + Cr01 + Y'03 + + + start + 8: + Cb10 + Y'10 + Cr10 + Y'11 + Cb11 + Y'12 + Cr11 + Y'13 + + + start + 16: + Cb20 + Y'20 + Cr20 + Y'21 + Cb21 + Y'22 + Cr21 + Y'23 + + + start + 24: + Cb30 + Y'30 + Cr30 + Y'31 + Cb31 + Y'32 + Cr31 + Y'33 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YCY + YCY + + + 1 + YCY + YCY + + + 2 + YCY + YCY + + + 3 + YCY + YCY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml b/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml new file mode 100644 index 00000000000..61f12a5e68d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-vyuy.xml @@ -0,0 +1,128 @@ + + + V4L2_PIX_FMT_VYUY ('VYUY') + &manvol; + + + V4L2_PIX_FMT_VYUY + Variation of +V4L2_PIX_FMT_YUYV with different order of samples +in memory + + + Description + + In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component. + + + <constant>V4L2_PIX_FMT_VYUY</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Cr00 + Y'00 + Cb00 + Y'01 + Cr01 + Y'02 + Cb01 + Y'03 + + + start + 8: + Cr10 + Y'10 + Cb10 + Y'11 + Cr11 + Y'12 + Cb11 + Y'13 + + + start + 16: + Cr20 + Y'20 + Cb20 + Y'21 + Cr21 + Y'22 + Cb21 + Y'23 + + + start + 24: + Cr30 + Y'30 + Cb30 + Y'31 + Cr31 + Y'32 + Cb31 + Y'33 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YCY + YCY + + + 1 + YCY + YCY + + + 2 + YCY + YCY + + + 3 + YCY + YCY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-y10.xml b/Documentation/DocBook/media/v4l/pixfmt-y10.xml new file mode 100644 index 00000000000..d065043db8d --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y10.xml @@ -0,0 +1,79 @@ + + + V4L2_PIX_FMT_Y10 ('Y10 ') + &manvol; + + + V4L2_PIX_FMT_Y10 + Grey-scale image + + + Description + + This is a grey-scale image with a depth of 10 bits per pixel. Pixels +are stored in 16-bit words with unused high bits padded with 0. The least +significant byte is stored at lower memory addresses (little-endian). + + + <constant>V4L2_PIX_FMT_Y10</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00low + Y'00high + Y'01low + Y'01high + Y'02low + Y'02high + Y'03low + Y'03high + + + start + 8: + Y'10low + Y'10high + Y'11low + Y'11high + Y'12low + Y'12high + Y'13low + Y'13high + + + start + 16: + Y'20low + Y'20high + Y'21low + Y'21high + Y'22low + Y'22high + Y'23low + Y'23high + + + start + 24: + Y'30low + Y'30high + Y'31low + Y'31high + Y'32low + Y'32high + Y'33low + Y'33high + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-y10b.xml b/Documentation/DocBook/media/v4l/pixfmt-y10b.xml new file mode 100644 index 00000000000..adb0ad808c9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y10b.xml @@ -0,0 +1,43 @@ + + + V4L2_PIX_FMT_Y10BPACK ('Y10B') + &manvol; + + + V4L2_PIX_FMT_Y10BPACK + Grey-scale image as a bit-packed array + + + Description + + This is a packed grey-scale image format with a depth of 10 bits per + pixel. Pixels are stored in a bit-packed array of 10bit bits per pixel, + with no padding between them and with the most significant bits coming + first from the left. + + + <constant>V4L2_PIX_FMT_Y10BPACK</constant> 4 pixel data stream taking 5 bytes + + + Bit-packed representation + pixels cross the byte boundary and have a ratio of 5 bytes for each 4 + pixels. + + + + + + Y'00[9:2] + Y'00[1:0]Y'01[9:4] + Y'01[3:0]Y'02[9:6] + Y'02[5:0]Y'03[9:8] + Y'03[7:0] + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-y12.xml b/Documentation/DocBook/media/v4l/pixfmt-y12.xml new file mode 100644 index 00000000000..ff417b858cc --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y12.xml @@ -0,0 +1,79 @@ + + + V4L2_PIX_FMT_Y12 ('Y12 ') + &manvol; + + + V4L2_PIX_FMT_Y12 + Grey-scale image + + + Description + + This is a grey-scale image with a depth of 12 bits per pixel. Pixels +are stored in 16-bit words with unused high bits padded with 0. The least +significant byte is stored at lower memory addresses (little-endian). + + + <constant>V4L2_PIX_FMT_Y12</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00low + Y'00high + Y'01low + Y'01high + Y'02low + Y'02high + Y'03low + Y'03high + + + start + 8: + Y'10low + Y'10high + Y'11low + Y'11high + Y'12low + Y'12high + Y'13low + Y'13high + + + start + 16: + Y'20low + Y'20high + Y'21low + Y'21high + Y'22low + Y'22high + Y'23low + Y'23high + + + start + 24: + Y'30low + Y'30high + Y'31low + Y'31high + Y'32low + Y'32high + Y'33low + Y'33high + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-y16.xml b/Documentation/DocBook/media/v4l/pixfmt-y16.xml new file mode 100644 index 00000000000..d5840401507 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y16.xml @@ -0,0 +1,89 @@ + + + V4L2_PIX_FMT_Y16 ('Y16 ') + &manvol; + + + V4L2_PIX_FMT_Y16 + Grey-scale image + + + Description + + This is a grey-scale image with a depth of 16 bits per +pixel. The least significant byte is stored at lower memory addresses +(little-endian). Note the actual sampling precision may be lower than +16 bits, for example 10 bits per pixel with values in range 0 to +1023. + + + <constant>V4L2_PIX_FMT_Y16</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00low + Y'00high + Y'01low + Y'01high + Y'02low + Y'02high + Y'03low + Y'03high + + + start + 8: + Y'10low + Y'10high + Y'11low + Y'11high + Y'12low + Y'12high + Y'13low + Y'13high + + + start + 16: + Y'20low + Y'20high + Y'21low + Y'21high + Y'22low + Y'22high + Y'23low + Y'23high + + + start + 24: + Y'30low + Y'30high + Y'31low + Y'31high + Y'32low + Y'32high + Y'33low + Y'33high + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-y41p.xml b/Documentation/DocBook/media/v4l/pixfmt-y41p.xml new file mode 100644 index 00000000000..73c8536efb0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-y41p.xml @@ -0,0 +1,157 @@ + + + V4L2_PIX_FMT_Y41P ('Y41P') + &manvol; + + + V4L2_PIX_FMT_Y41P + Format with ¼ horizontal chroma +resolution, also known as YUV 4:1:1 + + + Description + + In this format each 12 bytes is eight pixels. In the +twelve bytes are two CbCr pairs and eight Y's. The first CbCr pair +goes with the first four Y's, and the second CbCr pair goes with the +other four Y's. The Cb and Cr components have one fourth the +horizontal resolution of the Y component. + + Do not confuse this format with V4L2_PIX_FMT_YUV411P. +Y41P is derived from "YUV 4:1:1 packed", while +YUV411P stands for "YUV 4:1:1 planar". + + + <constant>V4L2_PIX_FMT_Y41P</constant> 8 × 4 +pixel image + + + Byte Order + Each cell is one byte. + + + + + + start + 0: + Cb00 + Y'00 + Cr00 + Y'01 + Cb01 + Y'02 + Cr01 + Y'03 + Y'04 + Y'05 + Y'06 + Y'07 + + + start + 12: + Cb10 + Y'10 + Cr10 + Y'11 + Cb11 + Y'12 + Cr11 + Y'13 + Y'14 + Y'15 + Y'16 + Y'17 + + + start + 24: + Cb20 + Y'20 + Cr20 + Y'21 + Cb21 + Y'22 + Cr21 + Y'23 + Y'24 + Y'25 + Y'26 + Y'27 + + + start + 36: + Cb30 + Y'30 + Cr30 + Y'31 + Cb31 + Y'32 + Cr31 + Y'33 + Y'34 + Y'35 + Y'36 + Y'37 + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + 45 + 67 + + + 0 + YYC + YY + YYC + YY + + + 1 + YYC + YY + YYC + YY + + + 2 + YYC + YY + YYC + YY + + + 3 + YYC + YY + YYC + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml new file mode 100644 index 00000000000..8eb4a193d77 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv410.xml @@ -0,0 +1,141 @@ + + + V4L2_PIX_FMT_YVU410 ('YVU9'), V4L2_PIX_FMT_YUV410 ('YUV9') + &manvol; + + + V4L2_PIX_FMT_YVU410 + V4L2_PIX_FMT_YUV410 + Planar formats with ¼ horizontal and +vertical chroma resolution, also known as YUV 4:1:0 + + + Description + + These are planar formats, as opposed to a packed format. +The three components are separated into three sub-images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +V4L2_PIX_FMT_YVU410, the Cr plane immediately +follows the Y plane in memory. The Cr plane is ¼ the width and +¼ the height of the Y plane (and of the image). Each Cr belongs +to 16 pixels, a four-by-four square of the image. Following the Cr +plane is the Cb plane, just like the Cr plane. +V4L2_PIX_FMT_YUV410 is the same, except the Cb +plane comes first, then the Cr plane. + + If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four Cx rows (including padding) are exactly as long as +one Y row (including padding). + + + <constant>V4L2_PIX_FMT_YVU410</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cr00 + + + start + 17: + Cb00 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + + + 1 + YY + YY + + + + C + + + + 2 + YY + YY + + + + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml new file mode 100644 index 00000000000..00e0960a986 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml @@ -0,0 +1,155 @@ + + + V4L2_PIX_FMT_YUV411P ('411P') + &manvol; + + + V4L2_PIX_FMT_YUV411P + Format with ¼ horizontal chroma resolution, +also known as YUV 4:1:1. Planar layout as opposed to +V4L2_PIX_FMT_Y41P + + + Description + + This format is not commonly used. This is a planar +format similar to the 4:2:2 planar format except with half as many +chroma. The three components are separated into three sub-images or +planes. The Y plane is first. The Y plane has one byte per pixel. The +Cb plane immediately follows the Y plane in memory. The Cb plane is +¼ the width of the Y plane (and of the image). Each Cb belongs +to 4 pixels all on the same row. For example, +Cb0 belongs to Y'00, +Y'01, Y'02 and +Y'03. Following the Cb plane is the Cr plane, +just like the Cb plane. + + If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four C x rows (including padding) is exactly as long as +one Y row (including padding). + + + <constant>V4L2_PIX_FMT_YUV411P</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cb00 + + + start + 17: + Cb10 + + + start + 18: + Cb20 + + + start + 19: + Cb30 + + + start + 20: + Cr00 + + + start + 21: + Cr10 + + + start + 22: + Cr20 + + + start + 23: + Cr30 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YYC + YY + + + 1 + YYC + YY + + + 2 + YYC + YY + + + 3 + YYC + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml new file mode 100644 index 00000000000..42d7de5e456 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv420.xml @@ -0,0 +1,157 @@ + + + V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12') + &manvol; + + + V4L2_PIX_FMT_YVU420 + V4L2_PIX_FMT_YUV420 + Planar formats with ½ horizontal and +vertical chroma resolution, also known as YUV 4:2:0 + + + Description + + These are planar formats, as opposed to a packed format. +The three components are separated into three sub- images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +V4L2_PIX_FMT_YVU420, the Cr plane immediately +follows the Y plane in memory. The Cr plane is half the width and half +the height of the Y plane (and of the image). Each Cr belongs to four +pixels, a two-by-two square of the image. For example, +Cr0 belongs to Y'00, +Y'01, Y'10, and +Y'11. Following the Cr plane is the Cb plane, +just like the Cr plane. V4L2_PIX_FMT_YUV420 is +the same except the Cb plane comes first, then the Cr plane. + + If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding). + + + <constant>V4L2_PIX_FMT_YVU420</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cr00 + Cr01 + + + start + 18: + Cr10 + Cr11 + + + start + 20: + Cb00 + Cb01 + + + start + 22: + Cb10 + Cb11 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml new file mode 100644 index 00000000000..f5d8f57495c --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml @@ -0,0 +1,162 @@ + + + V4L2_PIX_FMT_YUV420M ('YU12M') + &manvol; + + + V4L2_PIX_FMT_YUV420M + Variation of V4L2_PIX_FMT_YUV420 + with planes non contiguous in memory. + + + + Description + + This is a multi-planar format, as opposed to a packed format. +The three components are separated into three sub- images or planes. + +The Y plane is first. The Y plane has one byte per pixel. The Cb data +constitutes the second plane which is half the width and half +the height of the Y plane (and of the image). Each Cb belongs to four +pixels, a two-by-two square of the image. For example, +Cb0 belongs to Y'00, +Y'01, Y'10, and +Y'11. The Cr data, just like the Cb plane, is +in the third plane. + + If the Y plane has pad bytes after each row, then the Cb +and Cr planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding). + + V4L2_PIX_FMT_NV12M is intended to be +used only in drivers and applications that support the multi-planar API, +described in . + + + <constant>V4L2_PIX_FMT_YVU420M</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start0 + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start0 + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start0 + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start0 + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + + start1 + 0: + Cb00 + Cb01 + + + start1 + 2: + Cb10 + Cb11 + + + + start2 + 0: + Cr00 + Cr01 + + + start2 + 2: + Cr10 + Cr11 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YY + YY + + + + C + C + + + 1 + YY + YY + + + + + + 2 + YY + YY + + + + C + C + + + 3 + YY + YY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml new file mode 100644 index 00000000000..4348bd9f0d0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv422p.xml @@ -0,0 +1,161 @@ + + + V4L2_PIX_FMT_YUV422P ('422P') + &manvol; + + + V4L2_PIX_FMT_YUV422P + Format with ½ horizontal chroma resolution, +also known as YUV 4:2:2. Planar layout as opposed to +V4L2_PIX_FMT_YUYV + + + Description + + This format is not commonly used. This is a planar +version of the YUYV format. The three components are separated into +three sub-images or planes. The Y plane is first. The Y plane has one +byte per pixel. The Cb plane immediately follows the Y plane in +memory. The Cb plane is half the width of the Y plane (and of the +image). Each Cb belongs to two pixels. For example, +Cb0 belongs to Y'00, +Y'01. Following the Cb plane is the Cr plane, +just like the Cb plane. + + If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding). + + + <constant>V4L2_PIX_FMT_YUV422P</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Y'01 + Y'02 + Y'03 + + + start + 4: + Y'10 + Y'11 + Y'12 + Y'13 + + + start + 8: + Y'20 + Y'21 + Y'22 + Y'23 + + + start + 12: + Y'30 + Y'31 + Y'32 + Y'33 + + + start + 16: + Cb00 + Cb01 + + + start + 18: + Cb10 + Cb11 + + + start + 20: + Cb20 + Cb21 + + + start + 22: + Cb30 + Cb31 + + + start + 24: + Cr00 + Cr01 + + + start + 26: + Cr10 + Cr11 + + + start + 28: + Cr20 + Cr21 + + + start + 30: + Cr30 + Cr31 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YCY + YCY + + + 1 + YCY + YCY + + + 2 + YCY + YCY + + + 3 + YCY + YCY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml b/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml new file mode 100644 index 00000000000..bdb2ffacbbc --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yuyv.xml @@ -0,0 +1,128 @@ + + + V4L2_PIX_FMT_YUYV ('YUYV') + &manvol; + + + V4L2_PIX_FMT_YUYV + Packed format with ½ horizontal chroma +resolution, also known as YUV 4:2:2 + + + Description + + In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y component. +V4L2_PIX_FMT_YUYV is known in the Windows +environment as YUY2. + + + <constant>V4L2_PIX_FMT_YUYV</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Cb00 + Y'01 + Cr00 + Y'02 + Cb01 + Y'03 + Cr01 + + + start + 8: + Y'10 + Cb10 + Y'11 + Cr10 + Y'12 + Cb11 + Y'13 + Cr11 + + + start + 16: + Y'20 + Cb20 + Y'21 + Cr20 + Y'22 + Cb21 + Y'23 + Cr21 + + + start + 24: + Y'30 + Cb30 + Y'31 + Cr30 + Y'32 + Cb31 + Y'33 + Cr31 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YCY + YCY + + + 1 + YCY + YCY + + + 2 + YCY + YCY + + + 3 + YCY + YCY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml b/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml new file mode 100644 index 00000000000..40d17ae39dd --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt-yvyu.xml @@ -0,0 +1,128 @@ + + + V4L2_PIX_FMT_YVYU ('YVYU') + &manvol; + + + V4L2_PIX_FMT_YVYU + Variation of +V4L2_PIX_FMT_YUYV with different order of samples +in memory + + + Description + + In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component. + + + <constant>V4L2_PIX_FMT_YVYU</constant> 4 × 4 +pixel image + + + Byte Order. + Each cell is one byte. + + + + + + start + 0: + Y'00 + Cr00 + Y'01 + Cb00 + Y'02 + Cr01 + Y'03 + Cb01 + + + start + 8: + Y'10 + Cr10 + Y'11 + Cb10 + Y'12 + Cr11 + Y'13 + Cb11 + + + start + 16: + Y'20 + Cr20 + Y'21 + Cb20 + Y'22 + Cr21 + Y'23 + Cb21 + + + start + 24: + Y'30 + Cr30 + Y'31 + Cb30 + Y'32 + Cr31 + Y'33 + Cb31 + + + + + + + + + Color Sample Location. + + + + + + + 01 + 23 + + + 0 + YCY + YCY + + + 1 + YCY + YCY + + + 2 + YCY + YCY + + + 3 + YCY + YCY + + + + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml new file mode 100644 index 00000000000..deb660207f9 --- /dev/null +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -0,0 +1,951 @@ + Image Formats + + The V4L2 API was primarily designed for devices exchanging +image data with applications. The +v4l2_pix_format and v4l2_pix_format_mplane + structures define the format and layout of an image in memory. +The former is used with the single-planar API, while the latter is used with the +multi-planar version (see ). Image formats are +negotiated with the &VIDIOC-S-FMT; ioctl. (The explanations here focus on video +capturing and output, for overlay frame buffer formats see also +&VIDIOC-G-FBUF;.) + +
+ Single-planar format structure + + struct <structname>v4l2_pix_format</structname> + + &cs-str; + + + __u32 + width + Image width in pixels. + + + __u32 + height + Image height in pixels. + + + Applications set these fields to +request an image size, drivers return the closest possible values. In +case of planar formats the width and +height applies to the largest plane. To +avoid ambiguities drivers must return values rounded up to a multiple +of the scale factor of any smaller planes. For example when the image +format is YUV 4:2:0, width and +height must be multiples of two. + + + __u32 + pixelformat + The pixel format or type of compression, set by the +application. This is a little endian four character code. V4L2 defines +standard RGB formats in , YUV formats in , and reserved codes in + + + &v4l2-field; + field + Video images are typically interlaced. Applications +can request to capture or output only the top or bottom field, or both +fields interlaced or sequentially stored in one buffer or alternating +in separate buffers. Drivers return the actual field order selected. +For details see . + + + __u32 + bytesperline + Distance in bytes between the leftmost pixels in two +adjacent lines. + + + Both applications and drivers +can set this field to request padding bytes at the end of each line. +Drivers however may ignore the value requested by the application, +returning width times bytes per pixel or a +larger value required by the hardware. That implies applications can +just set this field to zero to get a reasonable +default.Video hardware may access padding bytes, +therefore they must reside in accessible memory. Consider cases where +padding bytes after the last line of an image cross a system page +boundary. Input devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.When the image format is planar the +bytesperline value applies to the largest +plane and is divided by the same factor as the +width field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a bytesperline value +rounded up to a multiple of the scale factor. + + + __u32 + sizeimage + Size in bytes of the buffer to hold a complete image, +set by the driver. Usually this is +bytesperline times +height. When the image consists of variable +length compressed data this is the maximum number of bytes required to +hold an image. + + + &v4l2-colorspace; + colorspace + This information supplements the +pixelformat and must be set by the driver, +see . + + + __u32 + priv + Reserved for custom (driver defined) additional +information about formats. When not used drivers and applications must +set this field to zero. + + + +
+
+ +
+ Multi-planar format structures + The v4l2_plane_pix_format structures define + size and layout for each of the planes in a multi-planar format. + The v4l2_pix_format_mplane structure contains + information common to all planes (such as image width and height) and + an array of v4l2_plane_pix_format structures, + describing all planes of that format. + + struct <structname>vl42_plane_pix_format</structname> + + &cs-str; + + + __u32 + sizeimage + Maximum size in bytes required for image data in this plane. + + + + __u16 + bytesperline + Distance in bytes between the leftmost pixels in two adjacent + lines. + + + __u16 + reserved[7] + Reserved for future extensions. Should be zeroed by the + application. + + + +
+ + struct <structname>v4l2_pix_format_mplane</structname> + + &cs-str; + + + __u32 + width + Image width in pixels. + + + __u32 + height + Image height in pixels. + + + __u32 + pixelformat + The pixel format. Both single- and multi-planar four character +codes can be used. + + + &v4l2-field; + field + See &v4l2-pix-format;. + + + &v4l2-colorspace; + colorspace + See &v4l2-pix-format;. + + + &v4l2-plane-pix-format; + plane_fmt[VIDEO_MAX_PLANES] + An array of structures describing format of each plane this + pixel format consists of. The number of valid entries in this array + has to be put in the num_planes + field. + + + __u8 + num_planes + Number of planes (i.e. separate memory buffers) for this format + and the number of valid entries in the + plane_fmt array. + + + __u8 + reserved[11] + Reserved for future extensions. Should be zeroed by the + application. + + + +
+
+ +
+ Standard Image Formats + + In order to exchange images between drivers and +applications, it is necessary to have standard image data formats +which both sides will interpret the same way. V4L2 includes several +such formats, and this section is intended to be an unambiguous +specification of the standard image data formats in V4L2. + + V4L2 drivers are not limited to these formats, however. +Driver-specific formats are possible. In that case the application may +depend on a codec to convert images to one of the standard formats +when needed. But the data can still be stored and retrieved in the +proprietary format. For example, a device may support a proprietary +compressed format. Applications can still capture and save the data in +the compressed format, saving much disk space, and later use a codec +to convert the images to the X Windows screen format when the video is +to be displayed. + + Even so, ultimately, some standard formats are needed, so +the V4L2 specification would not be complete without well-defined +standard formats. + + The V4L2 standard formats are mainly uncompressed formats. The +pixels are always arranged in memory from left to right, and from top +to bottom. The first byte of data in the image buffer is always for +the leftmost pixel of the topmost row. Following that is the pixel +immediately to its right, and so on until the end of the top row of +pixels. Following the rightmost pixel of the row there may be zero or +more bytes of padding to guarantee that each row of pixel data has a +certain alignment. Following the pad bytes, if any, is data for the +leftmost pixel of the second row from the top, and so on. The last row +has just as many pad bytes after it as the other rows. + + In V4L2 each format has an identifier which looks like +PIX_FMT_XXX, defined in the videodev.h header file. These identifiers +represent four character (FourCC) codes +which are also listed below, however they are not the same as those +used in the Windows world. + + For some formats, data is stored in separate, discontiguous +memory buffers. Those formats are identified by a separate set of FourCC codes +and are referred to as "multi-planar formats". For example, a YUV422 frame is +normally stored in one memory buffer, but it can also be placed in two or three +separate buffers, with Y component in one buffer and CbCr components in another +in the 2-planar version or with each component in its own buffer in the +3-planar case. Those sub-buffers are referred to as "planes". +
+ +
+ Colorspaces + + [intro] + + + + + + + Gamma Correction + + [to do] + E'R = f(R) + E'G = f(G) + E'B = f(B) + + + + Construction of luminance and color-difference +signals + + [to do] + E'Y = +CoeffR E'R ++ CoeffG E'G ++ CoeffB E'B + (E'R - E'Y) = E'R +- CoeffR E'R +- CoeffG E'G +- CoeffB E'B + (E'B - E'Y) = E'B +- CoeffR E'R +- CoeffG E'G +- CoeffB E'B + + + + Re-normalized color-difference signals + + The color-difference signals are scaled back to unity +range [-0.5;+0.5]: + KB = 0.5 / (1 - CoeffB) + KR = 0.5 / (1 - CoeffR) + PB = +KB (E'B - E'Y) = + 0.5 (CoeffR / CoeffB) E'R ++ 0.5 (CoeffG / CoeffB) E'G ++ 0.5 E'B + PR = +KR (E'R - E'Y) = + 0.5 E'R ++ 0.5 (CoeffG / CoeffR) E'G ++ 0.5 (CoeffB / CoeffR) E'B + + + + Quantization + + [to do] + Y' = (Lum. Levels - 1) · E'Y + Lum. Offset + CB = (Chrom. Levels - 1) +· PB + Chrom. Offset + CR = (Chrom. Levels - 1) +· PR + Chrom. Offset + Rounding to the nearest integer and clamping to the range +[0;255] finally yields the digital color components Y'CbCr +stored in YUV images. + + + + + + + ITU-R Rec. BT.601 color conversion + + Forward Transformation + + +int ER, EG, EB; /* gamma corrected RGB input [0;255] */ +int Y1, Cb, Cr; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +r = ER / 255.0; +g = EG / 255.0; +b = EB / 255.0; + +y1 = 0.299 * r + 0.587 * g + 0.114 * b; +pb = -0.169 * r - 0.331 * g + 0.5 * b; +pr = 0.5 * r - 0.419 * g - 0.081 * b; + +Y1 = clamp (219 * y1 + 16); +Cb = clamp (224 * pb + 128); +Cr = clamp (224 * pr + 128); + +/* or shorter */ + +y1 = 0.299 * ER + 0.587 * EG + 0.114 * EB; + +Y1 = clamp ( (219 / 255.0) * y1 + 16); +Cb = clamp (((224 / 255.0) / (2 - 2 * 0.114)) * (EB - y1) + 128); +Cr = clamp (((224 / 255.0) / (2 - 2 * 0.299)) * (ER - y1) + 128); + + + Inverse Transformation + + +int Y1, Cb, Cr; /* gamma pre-corrected input [0;255] */ +int ER, EG, EB; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +y1 = (255 / 219.0) * (Y1 - 16); +pb = (255 / 224.0) * (Cb - 128); +pr = (255 / 224.0) * (Cr - 128); + +r = 1.0 * y1 + 0 * pb + 1.402 * pr; +g = 1.0 * y1 - 0.344 * pb - 0.714 * pr; +b = 1.0 * y1 + 1.772 * pb + 0 * pr; + +ER = clamp (r * 255); /* [ok? one should prob. limit y1,pb,pr] */ +EG = clamp (g * 255); +EB = clamp (b * 255); + + + + + enum v4l2_colorspace + + + + + + + + + + + + + + + + + + Identifier + Value + Description + Chromaticities + The coordinates of the color primaries are +given in the CIE system (1931) + + White Point + Gamma Correction + Luminance E'Y + Quantization + + + Red + Green + Blue + Y' + Cb, Cr + + + + + V4L2_COLORSPACE_SMPTE170M + 1 + NTSC/PAL according to , + + x = 0.630, y = 0.340 + x = 0.310, y = 0.595 + x = 0.155, y = 0.070 + x = 0.3127, y = 0.3290, + Illuminant D65 + E' = 4.5 I for I ≤0.018, +1.099 I0.45 - 0.099 for 0.018 < I + 0.299 E'R ++ 0.587 E'G ++ 0.114 E'B + 219 E'Y + 16 + 224 PB,R + 128 + + + V4L2_COLORSPACE_SMPTE240M + 2 + 1125-Line (US) HDTV, see + x = 0.630, y = 0.340 + x = 0.310, y = 0.595 + x = 0.155, y = 0.070 + x = 0.3127, y = 0.3290, + Illuminant D65 + E' = 4 I for I ≤0.0228, +1.1115 I0.45 - 0.1115 for 0.0228 < I + 0.212 E'R ++ 0.701 E'G ++ 0.087 E'B + 219 E'Y + 16 + 224 PB,R + 128 + + + V4L2_COLORSPACE_REC709 + 3 + HDTV and modern devices, see + x = 0.640, y = 0.330 + x = 0.300, y = 0.600 + x = 0.150, y = 0.060 + x = 0.3127, y = 0.3290, + Illuminant D65 + E' = 4.5 I for I ≤0.018, +1.099 I0.45 - 0.099 for 0.018 < I + 0.2125 E'R ++ 0.7154 E'G ++ 0.0721 E'B + 219 E'Y + 16 + 224 PB,R + 128 + + + V4L2_COLORSPACE_BT878 + 4 + Broken Bt878 extents + The ubiquitous Bt878 video capture chip +quantizes E'Y to 238 levels, yielding a range +of Y' = 16 … 253, unlike Rec. 601 Y' = 16 … +235. This is not a typo in the Bt878 documentation, it has been +implemented in silicon. The chroma extents are unclear. + , + ? + ? + ? + ? + ? + 0.299 E'R ++ 0.587 E'G ++ 0.114 E'B + 237 E'Y + 16 + 224 PB,R + 128 (probably) + + + V4L2_COLORSPACE_470_SYSTEM_M + 5 + M/NTSC + No identifier exists for M/PAL which uses +the chromaticities of M/NTSC, the remaining parameters are equal to B and +G/PAL. + according to , + x = 0.67, y = 0.33 + x = 0.21, y = 0.71 + x = 0.14, y = 0.08 + x = 0.310, y = 0.316, Illuminant C + ? + 0.299 E'R ++ 0.587 E'G ++ 0.114 E'B + 219 E'Y + 16 + 224 PB,R + 128 + + + V4L2_COLORSPACE_470_SYSTEM_BG + 6 + 625-line PAL and SECAM systems according to , + x = 0.64, y = 0.33 + x = 0.29, y = 0.60 + x = 0.15, y = 0.06 + x = 0.313, y = 0.329, +Illuminant D65 + ? + 0.299 E'R ++ 0.587 E'G ++ 0.114 E'B + 219 E'Y + 16 + 224 PB,R + 128 + + + V4L2_COLORSPACE_JPEG + 7 + JPEG Y'CbCr, see , + ? + ? + ? + ? + ? + 0.299 E'R ++ 0.587 E'G ++ 0.114 E'B + 256 E'Y + 16 + Note JFIF quantizes +Y'PBPR in range [0;+1] and +[-0.5;+0.5] to 257 levels, however Y'CbCr signals +are still clamped to [0;255]. + + 256 PB,R + 128 + + + V4L2_COLORSPACE_SRGB + 8 + [?] + x = 0.640, y = 0.330 + x = 0.300, y = 0.600 + x = 0.150, y = 0.060 + x = 0.3127, y = 0.3290, + Illuminant D65 + E' = 4.5 I for I ≤0.018, +1.099 I0.45 - 0.099 for 0.018 < I + n/a + + + +
+
+ +
+ Indexed Format + + In this format each pixel is represented by an 8 bit index +into a 256 entry ARGB palette. It is intended for Video Output Overlays only. There are no ioctls to +access the palette, this must be done with ioctls of the Linux framebuffer API. + + + Indexed Image Format + + + + + + + + + + + + + + + + + + + + + Identifier + Code +   + Byte 0 + + +   +   + Bit + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_PIX_FMT_PAL8 + 'PAL8' + + i7 + i6 + i5 + i4 + i3 + i2 + i1 + i0 + + + +
+
+ +
+ RGB Formats + + &sub-packed-rgb; + &sub-sbggr8; + &sub-sgbrg8; + &sub-sgrbg8; + &sub-srggb8; + &sub-sbggr16; + &sub-srggb10; + &sub-srggb12; +
+ +
+ YUV Formats + + YUV is the format native to TV broadcast and composite video +signals. It separates the brightness information (Y) from the color +information (U and V or Cb and Cr). The color information consists of +red and blue color difference signals, this way +the green component can be reconstructed by subtracting from the +brightness component. See for conversion +examples. YUV was chosen because early television would only transmit +brightness information. To add color in a way compatible with existing +receivers a new signal carrier was added to transmit the color +difference signals. Secondary in the YUV format the U and V components +usually have lower resolution than the Y component. This is an analog +video compression technique taking advantage of a property of the +human visual system, being more sensitive to brightness +information. + + &sub-packed-yuv; + &sub-grey; + &sub-y10; + &sub-y12; + &sub-y10b; + &sub-y16; + &sub-yuyv; + &sub-uyvy; + &sub-yvyu; + &sub-vyuy; + &sub-y41p; + &sub-yuv420; + &sub-yuv420m; + &sub-yuv410; + &sub-yuv422p; + &sub-yuv411p; + &sub-nv12; + &sub-nv12m; + &sub-nv12mt; + &sub-nv16; + &sub-m420; +
+ +
+ Compressed Formats + + + Compressed Image Formats + + &cs-def; + + + Identifier + Code + Details + + + + + V4L2_PIX_FMT_JPEG + 'JPEG' + TBD. See also &VIDIOC-G-JPEGCOMP;, + &VIDIOC-S-JPEGCOMP;. + + + V4L2_PIX_FMT_MPEG + 'MPEG' + MPEG stream. The actual format is determined by +extended control V4L2_CID_MPEG_STREAM_TYPE, see +. + + + +
+
+ +
+ Reserved Format Identifiers + + These formats are not defined by this specification, they +are just listed for reference and to avoid naming conflicts. If you +want to register your own format, send an e-mail to the linux-media mailing +list &v4l-ml; for inclusion in the videodev2.h +file. If you want to share your format with other developers add a +link to your documentation and send a copy to the linux-media mailing list +for inclusion in this section. If you think your format should be listed +in a standard format section please make a proposal on the linux-media mailing +list. + + + Reserved Image Formats + + &cs-def; + + + Identifier + Code + Details + + + + + V4L2_PIX_FMT_DV + 'dvsd' + unknown + + + V4L2_PIX_FMT_ET61X251 + 'E625' + Compressed format of the ET61X251 driver. + + + V4L2_PIX_FMT_HI240 + 'HI24' + 8 bit RGB format used by the BTTV driver. + + + V4L2_PIX_FMT_HM12 + 'HM12' + YUV 4:2:0 format used by the +IVTV driver, +http://www.ivtvdriver.org/The format is documented in the +kernel sources in the file Documentation/video4linux/cx2341x/README.hm12 + + + + V4L2_PIX_FMT_CPIA1 + 'CPIA' + YUV format used by the gspca cpia1 driver. + + + V4L2_PIX_FMT_SPCA501 + 'S501' + YUYV per line used by the gspca driver. + + + V4L2_PIX_FMT_SPCA505 + 'S505' + YYUV per line used by the gspca driver. + + + V4L2_PIX_FMT_SPCA508 + 'S508' + YUVY per line used by the gspca driver. + + + V4L2_PIX_FMT_SPCA561 + 'S561' + Compressed GBRG Bayer format used by the gspca driver. + + + V4L2_PIX_FMT_SGRBG10DPCM8 + 'DB10' + 10 bit raw Bayer DPCM compressed to 8 bits. + + + V4L2_PIX_FMT_PAC207 + 'P207' + Compressed BGGR Bayer format used by the gspca driver. + + + V4L2_PIX_FMT_MR97310A + 'M310' + Compressed BGGR Bayer format used by the gspca driver. + + + V4L2_PIX_FMT_OV511 + 'O511' + OV511 JPEG format used by the gspca driver. + + + V4L2_PIX_FMT_OV518 + 'O518' + OV518 JPEG format used by the gspca driver. + + + V4L2_PIX_FMT_PJPG + 'PJPG' + Pixart 73xx JPEG format used by the gspca driver. + + + V4L2_PIX_FMT_SQ905C + '905C' + Compressed RGGB bayer format used by the gspca driver. + + + V4L2_PIX_FMT_MJPEG + 'MJPG' + Compressed format used by the Zoran driver + + + V4L2_PIX_FMT_PWC1 + 'PWC1' + Compressed format of the PWC driver. + + + V4L2_PIX_FMT_PWC2 + 'PWC2' + Compressed format of the PWC driver. + + + V4L2_PIX_FMT_SN9C10X + 'S910' + Compressed format of the SN9C102 driver. + + + V4L2_PIX_FMT_SN9C20X_I420 + 'S920' + YUV 4:2:0 format of the gspca sn9c20x driver. + + + V4L2_PIX_FMT_SN9C2028 + 'SONX' + Compressed GBRG bayer format of the gspca sn9c2028 driver. + + + V4L2_PIX_FMT_STV0680 + 'S680' + Bayer format of the gspca stv0680 driver. + + + V4L2_PIX_FMT_WNVA + 'WNVA' + Used by the Winnov Videum driver, +http://www.thedirks.org/winnov/ + + + V4L2_PIX_FMT_TM6000 + 'TM60' + Used by Trident tm6000 + + + V4L2_PIX_FMT_CIT_YYVYUY + 'CITV' + Used by xirlink CIT, found at IBM webcams. + Uses one line of Y then 1 line of VYUY + + + + V4L2_PIX_FMT_KONICA420 + 'KONI' + Used by Konica webcams. + YUV420 planar in blocks of 256 pixels. + + + + V4L2_PIX_FMT_YYUV + 'YYUV' + unknown + + + V4L2_PIX_FMT_Y4 + 'Y04 ' + Old 4-bit greyscale format. Only the least significant 4 bits of each byte are used, +the other bits are set to 0. + + + V4L2_PIX_FMT_Y6 + 'Y06 ' + Old 6-bit greyscale format. Only the least significant 6 bits of each byte are used, +the other bits are set to 0. + + + +
+
+ + diff --git a/Documentation/DocBook/media/v4l/planar-apis.xml b/Documentation/DocBook/media/v4l/planar-apis.xml new file mode 100644 index 00000000000..878ce204048 --- /dev/null +++ b/Documentation/DocBook/media/v4l/planar-apis.xml @@ -0,0 +1,62 @@ +
+ Single- and multi-planar APIs + + Some devices require data for each input or output video frame + to be placed in discontiguous memory buffers. In such cases, one + video frame has to be addressed using more than one memory address, i.e. one + pointer per "plane". A plane is a sub-buffer of the current frame. For + examples of such formats see . + + Initially, V4L2 API did not support multi-planar buffers and a set of + extensions has been introduced to handle them. Those extensions constitute + what is being referred to as the "multi-planar API". + + Some of the V4L2 API calls and structures are interpreted differently, + depending on whether single- or multi-planar API is being used. An application + can choose whether to use one or the other by passing a corresponding buffer + type to its ioctl calls. Multi-planar versions of buffer types are suffixed + with an `_MPLANE' string. For a list of available multi-planar buffer types + see &v4l2-buf-type;. + + +
+ Multi-planar formats + Multi-planar API introduces new multi-planar formats. Those formats + use a separate set of FourCC codes. It is important to distinguish between + the multi-planar API and a multi-planar format. Multi-planar API calls can + handle all single-planar formats as well (as long as they are passed in + multi-planar API structures), while the single-planar API cannot + handle multi-planar formats. +
+ +
+ Calls that distinguish between single and multi-planar APIs + + + &VIDIOC-QUERYCAP; + Two additional multi-planar capabilities are added. They can + be set together with non-multi-planar ones for devices that handle + both single- and multi-planar formats. + + + &VIDIOC-G-FMT;, &VIDIOC-S-FMT;, &VIDIOC-TRY-FMT; + New structures for describing multi-planar formats are added: + &v4l2-pix-format-mplane; and &v4l2-plane-pix-format;. Drivers may + define new multi-planar formats, which have distinct FourCC codes from + the existing single-planar ones. + + + + &VIDIOC-QBUF;, &VIDIOC-DQBUF;, &VIDIOC-QUERYBUF; + A new &v4l2-plane; structure for describing planes is added. + Arrays of this structure are passed in the new + m.planes field of &v4l2-buffer;. + + + + &VIDIOC-REQBUFS; + Will allocate multi-planar buffers as requested. + + +
+
diff --git a/Documentation/DocBook/media/v4l/remote_controllers.xml b/Documentation/DocBook/media/v4l/remote_controllers.xml new file mode 100644 index 00000000000..160e464d44b --- /dev/null +++ b/Documentation/DocBook/media/v4l/remote_controllers.xml @@ -0,0 +1,177 @@ +Remote Controllers +
+Introduction + +Currently, most analog and digital devices have a Infrared input for remote controllers. Each +manufacturer has their own type of control. It is not rare for the same manufacturer to ship different +types of controls, depending on the device. +Unfortunately, for several years, there was no effort to create uniform IR keycodes for +different devices. This caused the same IR keyname to be mapped completely differently on +different IR devices. This resulted that the same IR keyname to be mapped completely different on +different IR's. Due to that, V4L2 API now specifies a standard for mapping Media keys on IR. +This standard should be used by both V4L/DVB drivers and userspace applications +The modules register the remote as keyboard within the linux input layer. This means that the IR key strokes will look like normal keyboard key strokes (if CONFIG_INPUT_KEYBOARD is enabled). Using the event devices (CONFIG_INPUT_EVDEV) it is possible for applications to access the remote via /dev/input/event devices. + + +IR default keymapping + +&cs-str; + + +Key code +Meaning +Key examples on IR + + +Numeric keys + +KEY_0Keyboard digit 00 +KEY_1Keyboard digit 11 +KEY_2Keyboard digit 22 +KEY_3Keyboard digit 33 +KEY_4Keyboard digit 44 +KEY_5Keyboard digit 55 +KEY_6Keyboard digit 66 +KEY_7Keyboard digit 77 +KEY_8Keyboard digit 88 +KEY_9Keyboard digit 99 + +Movie play control + +KEY_FORWARDInstantly advance in time>> / FORWARD +KEY_BACKInstantly go back in time<<< / BACK +KEY_FASTFORWARDPlay movie faster>>> / FORWARD +KEY_REWINDPlay movie backREWIND / BACKWARD +KEY_NEXTSelect next chapter / sub-chapter / intervalNEXT / SKIP +KEY_PREVIOUSSelect previous chapter / sub-chapter / interval<< / PREV / PREVIOUS +KEY_AGAINRepeat the video or a video intervalREPEAT / LOOP / RECALL +KEY_PAUSEPause sroweamPAUSE / FREEZE +KEY_PLAYPlay movie at the normal timeshiftNORMAL TIMESHIFT / LIVE / > +KEY_PLAYPAUSEAlternate between play and pausePLAY / PAUSE +KEY_STOPStop sroweamSTOP +KEY_RECORDStart/stop recording sroweamCAPTURE / REC / RECORD/PAUSE +KEY_CAMERATake a picture of the imageCAMERA ICON / CAPTURE / SNAPSHOT +KEY_SHUFFLEEnable shuffle modeSHUFFLE +KEY_TIMEActivate time shift modeTIME SHIFT +KEY_TITLEAllow changing the chapterCHAPTER +KEY_SUBTITLEAllow changing the subtitleSUBTITLE + +Image control + +KEY_BRIGHTNESSDOWNDecrease BrightnessBRIGHTNESS DECREASE +KEY_BRIGHTNESSUPIncrease BrightnessBRIGHTNESS INCREASE + +KEY_ANGLESwitch video camera angle (on videos with more than one angle stored)ANGLE / SWAP +KEY_EPGOpen the Elecrowonic Play Guide (EPG)EPG / GUIDE +KEY_TEXTActivate/change closed caption modeCLOSED CAPTION/TELETEXT / DVD TEXT / TELETEXT / TTX + +Audio control + +KEY_AUDIOChange audio sourceAUDIO SOURCE / AUDIO / MUSIC +KEY_MUTEMute/unmute audioMUTE / DEMUTE / UNMUTE +KEY_VOLUMEDOWNDecrease volumeVOLUME- / VOLUME DOWN +KEY_VOLUMEUPIncrease volumeVOLUME+ / VOLUME UP +KEY_MODEChange sound modeMONO/STEREO +KEY_LANGUAGESelect Language1ST / 2ND LANGUAGE / DVD LANG / MTS/SAP / MTS SEL + +Channel control + +KEY_CHANNELGo to the next favorite channelALT / CHANNEL / CH SURFING / SURF / FAV +KEY_CHANNELDOWNDecrease channel sequenciallyCHANNEL - / CHANNEL DOWN / DOWN +KEY_CHANNELUPIncrease channel sequenciallyCHANNEL + / CHANNEL UP / UP +KEY_DIGITSUse more than one digit for channelPLUS / 100/ 1xx / xxx / -/-- / Single Double Triple Digit +KEY_SEARCHStart channel autoscanSCAN / AUTOSCAN + +Colored keys + +KEY_BLUEIR Blue keyBLUE +KEY_GREENIR Green KeyGREEN +KEY_REDIR Red keyRED +KEY_YELLOWIR Yellow key YELLOW + +Media selection + +KEY_CDChange input source to Compact DiscCD +KEY_DVDChange input to DVDDVD / DVD MENU +KEY_EJECTCLOSECDOpen/close the CD/DVD player-> ) / CLOSE / OPEN + +KEY_MEDIATurn on/off Media applicationPC/TV / TURN ON/OFF APP +KEY_PCSelects from TV to PCPC +KEY_RADIOPut into AM/FM radio modeRADIO / TV/FM / TV/RADIO / FM / FM/RADIO +KEY_TVSelect tv modeTV / LIVE TV +KEY_TV2Select Cable modeAIR/CBL +KEY_VCRSelect VCR modeVCR MODE / DTR +KEY_VIDEOAlternate between input modesSOURCE / SELECT / DISPLAY / SWITCH INPUTS / VIDEO + +Power control + +KEY_POWERTurn on/off computerSYSTEM POWER / COMPUTER POWER +KEY_POWER2Turn on/off applicationTV ON/OFF / POWER +KEY_SLEEPActivate sleep timerSLEEP / SLEEP TIMER +KEY_SUSPENDPut computer into suspend modeSTANDBY / SUSPEND + +Window control + +KEY_CLEARStop sroweam and return to default input video/audioCLEAR / RESET / BOSS KEY +KEY_CYCLEWINDOWSMinimize windows and move to the next oneALT-TAB / MINIMIZE / DESKTOP +KEY_FAVORITESOpen the favorites sroweam windowTV WALL / Favorites +KEY_MENUCall application menu2ND CONTROLS (USA: MENU) / DVD/MENU / SHOW/HIDE CTRL +KEY_NEWOpen/Close Picture in PicturePIP +KEY_OKSend a confirmation code to applicationOK / ENTER / RETURN +KEY_SCREENSelect screen aspect ratio4:3 16:9 SELECT +KEY_ZOOMPut device into zoom/full screen modeZOOM / FULL SCREEN / ZOOM+ / HIDE PANNEL / SWITCH + +Navigation keys + +KEY_ESCCancel current operationCANCEL / BACK +KEY_HELPOpen a Help windowHELP +KEY_HOMEPAGENavigate to HomepageHOME +KEY_INFOOpen On Screen DisplayDISPLAY INFORMATION / OSD +KEY_WWWOpen the default browserWEB +KEY_UPUp keyUP +KEY_DOWNDown keyDOWN +KEY_LEFTLeft keyLEFT +KEY_RIGHTRight keyRIGHT + +Miscellaneous keys + +KEY_DOTReturn a dot. +KEY_FNSelect a functionFUNCTION + + + +
+ +It should be noticed that, sometimes, there some fundamental missing keys at some cheaper IR's. Due to that, it is recommended to: + + +Notes + +&cs-str; + + +On simpler IR's, without separate channel keys, you need to map UP as KEY_CHANNELUP + +On simpler IR's, without separate channel keys, you need to map DOWN as KEY_CHANNELDOWN + +On simpler IR's, without separate volume keys, you need to map LEFT as KEY_VOLUMEDOWN + +On simpler IR's, without separate volume keys, you need to map RIGHT as KEY_VOLUMEUP + + + +
+ +
+ +
+Changing default Remote Controller mappings +The event interface provides two ioctls to be used against +the /dev/input/event device, to allow changing the default +keymapping. + +This program demonstrates how to replace the keymap tables. +&sub-keytable-c; +
+ +&sub-lirc_device_interface; diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml new file mode 100644 index 00000000000..8d3409d2c63 --- /dev/null +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -0,0 +1,2572 @@ +
+ Media Bus Formats + + + struct <structname>v4l2_mbus_framefmt</structname> + + &cs-str; + + + __u32 + width + Image width, in pixels. + + + __u32 + height + Image height, in pixels. + + + __u32 + code + Format code, from &v4l2-mbus-pixelcode;. + + + __u32 + field + Field order, from &v4l2-field;. See + for details. + + + __u32 + colorspace + Image colorspace, from &v4l2-colorspace;. See + for details. + + + __u32 + reserved[7] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ +
+ Media Bus Pixel Codes + + The media bus pixel codes describe image formats as flowing over + physical busses (both between separate physical components and inside SoC + devices). This should not be confused with the V4L2 pixel formats that + describe, using four character codes, image formats as stored in memory. + + + While there is a relationship between image formats on busses and + image formats in memory (a raw Bayer image won't be magically converted to + JPEG just by storing it to memory), there is no one-to-one correspondance + between them. + +
+ Packed RGB Formats + + Those formats transfer pixel data as red, green and blue components. + The format code is made of the following information. + + The red, green and blue components order code, as encoded in a + pixel sample. Possible values are RGB and BGR. + The number of bits per component, for each component. The values + can be different for all components. Common values are 555 and 565. + + The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1 and 2. + The bus width. + For formats where the total number of bits per pixel is smaller + than the number of bus samples per pixel times the bus width, a padding + value stating if the bytes are padded in their most high order bits + (PADHI) or low order bits (PADLO). + For formats where the number of bus samples per pixel is larger + than 1, an endianness value stating if the pixel is transferred MSB first + (BE) or LSB first (LE). + + + + For instance, a format where pixels are encoded as 5-bits red, 5-bits + green and 5-bit blue values padded on the high bit, transferred as 2 8-bit + samples per pixel with the most significant bits (padding, red and half of + the green value) transferred first will be named + V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE. + + + The following tables list existing packet RGB formats. + + + RGB formats + + + + + + + + + + + + + + + + Identifier + Code + + Data organization + + + + + Bit + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_MBUS_FMT_RGB444_2X8_PADHI_BE + 0x1001 + + 0 + 0 + 0 + 0 + r3 + r2 + r1 + r0 + + + + + + g3 + g2 + g1 + g0 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_RGB444_2X8_PADHI_LE + 0x1002 + + g3 + g2 + g1 + g0 + b3 + b2 + b1 + b0 + + + + + + 0 + 0 + 0 + 0 + r3 + r2 + r1 + r0 + + + V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE + 0x1003 + + 0 + r4 + r3 + r2 + r1 + r0 + g4 + g3 + + + + + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_RGB555_2X8_PADHI_LE + 0x1004 + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + + + + 0 + r4 + r3 + r2 + r1 + r0 + g4 + g3 + + + V4L2_MBUS_FMT_BGR565_2X8_BE + 0x1005 + + b4 + b3 + b2 + b1 + b0 + g5 + g4 + g3 + + + + + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + + V4L2_MBUS_FMT_BGR565_2X8_LE + 0x1006 + + g2 + g1 + g0 + r4 + r3 + r2 + r1 + r0 + + + + + + b4 + b3 + b2 + b1 + b0 + g5 + g4 + g3 + + + V4L2_MBUS_FMT_RGB565_2X8_BE + 0x1007 + + r4 + r3 + r2 + r1 + r0 + g5 + g4 + g3 + + + + + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_RGB565_2X8_LE + 0x1008 + + g2 + g1 + g0 + b4 + b3 + b2 + b1 + b0 + + + + + + r4 + r3 + r2 + r1 + r0 + g5 + g4 + g3 + + + +
+
+ +
+ Bayer Formats + + Those formats transfer pixel data as red, green and blue components. + The format code is made of the following information. + + The red, green and blue components order code, as encoded in a + pixel sample. The possible values are shown in . + The number of bits per pixel component. All components are + transferred on the same number of bits. Common values are 8, 10 and 12. + + If the pixel components are DPCM-compressed, a mention of the + DPCM compression and the number of bits per compressed pixel component. + + The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1 and 2. + The bus width. + For formats where the total number of bits per pixel is smaller + than the number of bus samples per pixel times the bus width, a padding + value stating if the bytes are padded in their most high order bits + (PADHI) or low order bits (PADLO). + For formats where the number of bus samples per pixel is larger + than 1, an endianness value stating if the pixel is transferred MSB first + (BE) or LSB first (LE). + + + + For instance, a format with uncompressed 10-bit Bayer components + arranged in a red, green, green, blue pattern transferred as 2 8-bit + samples per pixel with the least significant bits transferred first will + be named V4L2_MBUS_FMT_SRGGB10_2X8_PADHI_LE. + + +
+ Bayer Patterns + + + + + + + + + Bayer filter color patterns + + +
+ + The following table lists existing packet Bayer formats. The data + organization is given as an example for the first pixel only. + + + Bayer Formats + + + + + + + + + + + + + + + + + + + + Identifier + Code + + Data organization + + + + + Bit + 11 + 10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_MBUS_FMT_SBGGR8_1X8 + 0x3001 + + - + - + - + - + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_SGBRG8_1X8 + 0x3013 + + - + - + - + - + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SGRBG8_1X8 + 0x3002 + + - + - + - + - + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SRGGB8_1X8 + 0x3014 + + - + - + - + - + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + V4L2_MBUS_FMT_SBGGR10_DPCM8_1X8 + 0x300b + + - + - + - + - + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_SGBRG10_DPCM8_1X8 + 0x300c + + - + - + - + - + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SGRBG10_DPCM8_1X8 + 0x3009 + + - + - + - + - + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SRGGB10_DPCM8_1X8 + 0x300d + + - + - + - + - + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_BE + 0x3003 + + - + - + - + - + 0 + 0 + 0 + 0 + 0 + 0 + b9 + b8 + + + + + + - + - + - + - + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_LE + 0x3004 + + - + - + - + - + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + + + + - + - + - + - + 0 + 0 + 0 + 0 + 0 + 0 + b9 + b8 + + + V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_BE + 0x3005 + + - + - + - + - + b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + + + + + + - + - + - + - + b1 + b0 + 0 + 0 + 0 + 0 + 0 + 0 + + + V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_LE + 0x3006 + + - + - + - + - + b1 + b0 + 0 + 0 + 0 + 0 + 0 + 0 + + + + + + - + - + - + - + b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + + + V4L2_MBUS_FMT_SBGGR10_1X10 + 0x3007 + + - + - + b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_SGBRG10_1X10 + 0x300e + + - + - + g9 + g8 + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SGRBG10_1X10 + 0x300a + + - + - + g9 + g8 + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SRGGB10_1X10 + 0x300f + + - + - + r9 + r8 + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + V4L2_MBUS_FMT_SBGGR12_1X12 + 0x3008 + + b11 + b10 + b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + b1 + b0 + + + V4L2_MBUS_FMT_SGBRG12_1X12 + 0x3010 + + g11 + g10 + g9 + g8 + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SGRBG12_1X12 + 0x3011 + + g11 + g10 + g9 + g8 + g7 + g6 + g5 + g4 + g3 + g2 + g1 + g0 + + + V4L2_MBUS_FMT_SRGGB12_1X12 + 0x3012 + + r11 + r10 + r9 + r8 + r7 + r6 + r5 + r4 + r3 + r2 + r1 + r0 + + + +
+
+ +
+ Packed YUV Formats + + Those data formats transfer pixel data as (possibly downsampled) Y, U + and V components. The format code is made of the following information. + + The Y, U and V components order code, as transferred on the + bus. Possible values are YUYV, UYVY, YVYU and VYUY. + The number of bits per pixel component. All components are + transferred on the same number of bits. Common values are 8, 10 and 12. + + The number of bus samples per pixel. Pixels that are wider than + the bus width must be transferred in multiple samples. Common values are + 1, 1.5 (encoded as 1_5) and 2. + The bus width. When the bus width is larger than the number of + bits per pixel component, several components are packed in a single bus + sample. The components are ordered as specified by the order code, with + components on the left of the code transferred in the high order bits. + Common values are 8 and 16. + + + + + For instance, a format where pixels are encoded as 8-bit YUV values + downsampled to 4:2:2 and transferred as 2 8-bit bus samples per pixel in the + U, Y, V, Y order will be named V4L2_MBUS_FMT_UYVY8_2X8. + + + The following table lisst existing packet YUV formats. + + + YUV Formats + + + + + + + + + + + + + + + + + + + + + + + + + + + + Identifier + Code + + Data organization + + + + + Bit + 19 + 18 + 17 + 16 + 15 + 14 + 13 + 12 + 11 + 10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 + 0 + + + + + V4L2_MBUS_FMT_Y8_1X8 + 0x2001 + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_UYVY8_1_5X8 + 0x2002 + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_VYUY8_1_5X8 + 0x2003 + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_YUYV8_1_5X8 + 0x2004 + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + V4L2_MBUS_FMT_YVYU8_1_5X8 + 0x2005 + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + V4L2_MBUS_FMT_UYVY8_2X8 + 0x2006 + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_VYUY8_2X8 + 0x2007 + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_YUYV8_2X8 + 0x2008 + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + V4L2_MBUS_FMT_YVYU8_2X8 + 0x2009 + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + V4L2_MBUS_FMT_Y10_1X10 + 0x200a + + - + - + - + - + - + - + - + - + - + - + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_YUYV10_2X10 + 0x200b + + - + - + - + - + - + - + - + - + - + - + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + u9 + u8 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + - + - + - + - + - + - + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + v9 + v8 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + V4L2_MBUS_FMT_YVYU10_2X10 + 0x200c + + - + - + - + - + - + - + - + - + - + - + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + v9 + v8 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + - + - + - + - + - + - + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + - + - + - + - + - + - + u9 + u8 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + V4L2_MBUS_FMT_Y12_1X12 + 0x2013 + + - + - + - + - + - + - + - + - + y11 + y10 + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_UYVY8_1X16 + 0x200f + + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_VYUY8_1X16 + 0x2010 + + - + - + - + - + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + + + + - + - + - + - + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + + + V4L2_MBUS_FMT_YUYV8_1X16 + 0x2011 + + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + V4L2_MBUS_FMT_YVYU8_1X16 + 0x2012 + + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + - + - + - + - + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + V4L2_MBUS_FMT_YUYV10_1X20 + 0x200d + + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + u9 + u8 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + + + + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + v9 + v8 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + V4L2_MBUS_FMT_YVYU10_1X20 + 0x200e + + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + v9 + v8 + v7 + v6 + v5 + v4 + v3 + v2 + v1 + v0 + + + + + + y9 + y8 + y7 + y6 + y5 + y4 + y3 + y2 + y1 + y0 + u9 + u8 + u7 + u6 + u5 + u4 + u3 + u2 + u1 + u0 + + + +
+
+ +
+ JPEG Compressed Formats + + Those data formats consist of an ordered sequence of 8-bit bytes + obtained from JPEG compression process. Additionally to the + _JPEG prefix the format code is made of + the following information. + + The number of bus samples per entropy encoded byte. + The bus width. + + + + For instance, for a JPEG baseline process and an 8-bit bus width + the format will be named V4L2_MBUS_FMT_JPEG_1X8. + + + The following table lists existing JPEG compressed formats. + + + JPEG Formats + + + + + + + Identifier + Code + Remarks + + + + + V4L2_MBUS_FMT_JPEG_1X8 + 0x4001 + Besides of its usage for the parallel bus this format is + recommended for transmission of JPEG data over MIPI CSI bus + using the User Defined 8-bit Data types. + + + + +
+
+
+
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml new file mode 100644 index 00000000000..a7fd76d0dac --- /dev/null +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -0,0 +1,539 @@ + + + + Michael + Schimek + H + +
+ mschimek@gmx.at +
+ + + + + Bill + Dirks + + Original author of the V4L2 API and +documentation. + + + + Hans + Verkuil + Designed and documented the VIDIOC_LOG_STATUS ioctl, +the extended control ioctls and major parts of the sliced VBI +API. + +
+ hverkuil@xs4all.nl +
+ + + + + Martin + Rubli + + Designed and documented the VIDIOC_ENUM_FRAMESIZES +and VIDIOC_ENUM_FRAMEINTERVALS ioctls. + + + + Andy + Walls + Documented the fielded V4L2_MPEG_STREAM_VBI_FMT_IVTV +MPEG stream embedded, sliced VBI data format in this specification. + + +
+ awalls@md.metrocast.net +
+ + + + + Mauro + Carvalho Chehab + Documented libv4l, designed and added v4l2grab example, +Remote Controller chapter. + +
+ mchehab@redhat.com +
+ + + + + Muralidharan + Karicheri + Documented the Digital Video timings API. + +
+ m-karicheri2@ti.com +
+ + + + + Pawel + Osciak + Designed and documented the multi-planar API. + +
+ pawel AT osciak.com +
+ + + + + + 1999 + 2000 + 2001 + 2002 + 2003 + 2004 + 2005 + 2006 + 2007 + 2008 + 2009 + 2010 + 2011 + Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin +Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab, + Pawel Osciak + + + Except when explicitly stated as GPL, programming examples within + this part can be used and distributed without restrictions. + + + + + + + 2.6.39 + 2011-03-01 + mcc, po + Removed VIDIOC_*_OLD from videodev2.h header and update it to reflect latest changes. Added the multi-planar API. + + + + 2.6.37 + 2010-08-06 + hv + Removed obsolete vtx (videotext) API. + + + + 2.6.33 + 2009-12-03 + mk + Added documentation for the Digital Video timings API. + + + + 2.6.32 + 2009-08-31 + mcc + Now, revisions will match the kernel version where +the V4L2 API changes will be used by the Linux Kernel. +Also added Remote Controller chapter. + + + + 0.29 + 2009-08-26 + ev + Added documentation for string controls and for FM Transmitter controls. + + + + 0.28 + 2009-08-26 + gl + Added V4L2_CID_BAND_STOP_FILTER documentation. + + + + 0.27 + 2009-08-15 + mcc + Added libv4l and Remote Controller documentation; +added v4l2grab and keytable application examples. + + + + 0.26 + 2009-07-23 + hv + Finalized the RDS capture API. Added modulator and RDS encoder +capabilities. Added support for string controls. + + + + 0.25 + 2009-01-18 + hv + Added pixel formats VYUY, NV16 and NV61, and changed +the debug ioctls VIDIOC_DBG_G/S_REGISTER and VIDIOC_DBG_G_CHIP_IDENT. +Added camera controls V4L2_CID_ZOOM_ABSOLUTE, V4L2_CID_ZOOM_RELATIVE, +V4L2_CID_ZOOM_CONTINUOUS and V4L2_CID_PRIVACY. + + + + 0.24 + 2008-03-04 + mhs + Added pixel formats Y16 and SBGGR16, new controls +and a camera controls class. Removed VIDIOC_G/S_MPEGCOMP. + + + + 0.23 + 2007-08-30 + mhs + Fixed a typo in VIDIOC_DBG_G/S_REGISTER. +Clarified the byte order of packed pixel formats. + + + + 0.22 + 2007-08-29 + mhs + Added the Video Output Overlay interface, new MPEG +controls, V4L2_FIELD_INTERLACED_TB and V4L2_FIELD_INTERLACED_BT, +VIDIOC_DBG_G/S_REGISTER, VIDIOC_(TRY_)ENCODER_CMD, +VIDIOC_G_CHIP_IDENT, VIDIOC_G_ENC_INDEX, new pixel formats. +Clarifications in the cropping chapter, about RGB pixel formats, the +mmap(), poll(), select(), read() and write() functions. Typographical +fixes. + + + + 0.21 + 2006-12-19 + mhs + Fixed a link in the VIDIOC_G_EXT_CTRLS section. + + + + 0.20 + 2006-11-24 + mhs + Clarified the purpose of the audioset field in +struct v4l2_input and v4l2_output. + + + + 0.19 + 2006-10-19 + mhs + Documented V4L2_PIX_FMT_RGB444. + + + + 0.18 + 2006-10-18 + mhs + Added the description of extended controls by Hans +Verkuil. Linked V4L2_PIX_FMT_MPEG to V4L2_CID_MPEG_STREAM_TYPE. + + + + 0.17 + 2006-10-12 + mhs + Corrected V4L2_PIX_FMT_HM12 description. + + + + 0.16 + 2006-10-08 + mhs + VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS are now part of the API. + + + + 0.15 + 2006-09-23 + mhs + Cleaned up the bibliography, added BT.653 and +BT.1119. capture.c/start_capturing() for user pointer I/O did not +initialize the buffer index. Documented the V4L MPEG and MJPEG +VID_TYPEs and V4L2_PIX_FMT_SBGGR8. Updated the list of reserved pixel +formats. See the history chapter for API changes. + + + + 0.14 + 2006-09-14 + mr + Added VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS proposal for frame format enumeration of +digital devices. + + + + 0.13 + 2006-04-07 + mhs + Corrected the description of struct v4l2_window +clips. New V4L2_STD_ and V4L2_TUNER_MODE_LANG1_LANG2 +defines. + + + + 0.12 + 2006-02-03 + mhs + Corrected the description of struct +v4l2_captureparm and v4l2_outputparm. + + + + 0.11 + 2006-01-27 + mhs + Improved the description of struct +v4l2_tuner. + + + + 0.10 + 2006-01-10 + mhs + VIDIOC_G_INPUT and VIDIOC_S_PARM +clarifications. + + + + 0.9 + 2005-11-27 + mhs + Improved the 525 line numbering diagram. Hans +Verkuil and I rewrote the sliced VBI section. He also contributed a +VIDIOC_LOG_STATUS page. Fixed VIDIOC_S_STD call in the video standard +selection example. Various updates. + + + + 0.8 + 2004-10-04 + mhs + Somehow a piece of junk slipped into the capture +example, removed. + + + + 0.7 + 2004-09-19 + mhs + Fixed video standard selection, control +enumeration, downscaling and aspect example. Added read and user +pointer i/o to video capture example. + + + + 0.6 + 2004-08-01 + mhs + v4l2_buffer changes, added video capture example, +various corrections. + + + + 0.5 + 2003-11-05 + mhs + Pixel format erratum. + + + + 0.4 + 2003-09-17 + mhs + Corrected source and Makefile to generate a PDF. +SGML fixes. Added latest API changes. Closed gaps in the history +chapter. + + + + 0.3 + 2003-02-05 + mhs + Another draft, more corrections. + + + + 0.2 + 2003-01-15 + mhs + Second draft, with corrections pointed out by Gerd +Knorr. + + + + 0.1 + 2002-12-01 + mhs + First draft, based on documentation by Bill Dirks +and discussions on the V4L mailing list. + + + + +Video for Linux Two API Specification + Revision 2.6.39 + + + &sub-common; + + + + &sub-pixfmt; + + + + &sub-io; + + + + Interfaces + +
&sub-dev-capture;
+
&sub-dev-overlay;
+
&sub-dev-output;
+
&sub-dev-osd;
+
&sub-dev-codec;
+
&sub-dev-effect;
+
&sub-dev-raw-vbi;
+
&sub-dev-sliced-vbi;
+
&sub-dev-teletext;
+
&sub-dev-radio;
+
&sub-dev-rds;
+
&sub-dev-event;
+
&sub-dev-subdev;
+ + + + &sub-driver; + + + + &sub-libv4l; + + + + &sub-compat; + + + + Function Reference + + + + &sub-close; + &sub-ioctl; + + &sub-cropcap; + &sub-dbg-g-chip-ident; + &sub-dbg-g-register; + &sub-dqevent; + &sub-encoder-cmd; + &sub-enumaudio; + &sub-enumaudioout; + &sub-enum-dv-presets; + &sub-enum-fmt; + &sub-enum-framesizes; + &sub-enum-frameintervals; + &sub-enuminput; + &sub-enumoutput; + &sub-enumstd; + &sub-g-audio; + &sub-g-audioout; + &sub-g-crop; + &sub-g-ctrl; + &sub-g-dv-preset; + &sub-g-dv-timings; + &sub-g-enc-index; + &sub-g-ext-ctrls; + &sub-g-fbuf; + &sub-g-fmt; + &sub-g-frequency; + &sub-g-input; + &sub-g-jpegcomp; + &sub-g-modulator; + &sub-g-output; + &sub-g-parm; + &sub-g-priority; + &sub-g-sliced-vbi-cap; + &sub-g-std; + &sub-g-tuner; + &sub-log-status; + &sub-overlay; + &sub-qbuf; + &sub-querybuf; + &sub-querycap; + &sub-queryctrl; + &sub-query-dv-preset; + &sub-querystd; + &sub-reqbufs; + &sub-s-hw-freq-seek; + &sub-streamon; + &sub-subdev-enum-frame-interval; + &sub-subdev-enum-frame-size; + &sub-subdev-enum-mbus-code; + &sub-subdev-g-crop; + &sub-subdev-g-fmt; + &sub-subdev-g-frame-interval; + &sub-subscribe-event; + + &sub-mmap; + &sub-munmap; + &sub-open; + &sub-poll; + &sub-read; + &sub-select; + &sub-write; + + + + Video For Linux Two Header File + &sub-videodev2-h; + + + + Video Capture Example + &sub-capture-c; + + + + Video Grabber example using libv4l + This program demonstrates how to grab V4L2 images in ppm format by +using libv4l handlers. The advantage is that this grabber can potentially work +with any V4L2 driver. + &sub-v4l2grab-c; + + + &sub-media-indices; + + &sub-biblio; + diff --git a/Documentation/DocBook/media/v4l/v4l2grab.c.xml b/Documentation/DocBook/media/v4l/v4l2grab.c.xml new file mode 100644 index 00000000000..bed12e40be2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/v4l2grab.c.xml @@ -0,0 +1,164 @@ + +/* V4L2 video picture grabber + Copyright (C) 2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <linux/videodev2.h> +#include "../libv4l/include/libv4l2.h" + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +struct buffer { + void *start; + size_t length; +}; + +static void xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = v4l2_ioctl(fh, request, arg); + } while (r == -1 && ((errno == EINTR) || (errno == EAGAIN))); + + if (r == -1) { + fprintf(stderr, "error %d, %s\n", errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +int main(int argc, char **argv) +{ + struct v4l2_format fmt; + struct v4l2_buffer buf; + struct v4l2_requestbuffers req; + enum v4l2_buf_type type; + fd_set fds; + struct timeval tv; + int r, fd = -1; + unsigned int i, n_buffers; + char *dev_name = "/dev/video0"; + char out_name[256]; + FILE *fout; + struct buffer *buffers; + + fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0); + if (fd < 0) { + perror("Cannot open device"); + exit(EXIT_FAILURE); + } + + CLEAR(fmt); + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + xioctl(fd, VIDIOC_S_FMT, &fmt); + if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) { + printf("Libv4l didn't accept RGB24 format. Can't proceed.\n"); + exit(EXIT_FAILURE); + } + if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480)) + printf("Warning: driver is sending image at %dx%d\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + + CLEAR(req); + req.count = 2; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_REQBUFS, &req); + + buffers = calloc(req.count, sizeof(*buffers)); + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + xioctl(fd, VIDIOC_QUERYBUF, &buf); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = v4l2_mmap(NULL, buf.length, + PROT_READ | PROT_WRITE, MAP_SHARED, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) { + perror("mmap"); + exit(EXIT_FAILURE); + } + } + + for (i = 0; i < n_buffers; ++i) { + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + xioctl(fd, VIDIOC_QBUF, &buf); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + xioctl(fd, VIDIOC_STREAMON, &type); + for (i = 0; i < 20; i++) { + do { + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + } while ((r == -1 && (errno = EINTR))); + if (r == -1) { + perror("select"); + return errno; + } + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_DQBUF, &buf); + + sprintf(out_name, "out%03d.ppm", i); + fout = fopen(out_name, "w"); + if (!fout) { + perror("Cannot open image"); + exit(EXIT_FAILURE); + } + fprintf(fout, "P6\n%d %d 255\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + fwrite(buffers[buf.index].start, buf.bytesused, 1, fout); + fclose(fout); + + xioctl(fd, VIDIOC_QBUF, &buf); + } + + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + xioctl(fd, VIDIOC_STREAMOFF, &type); + for (i = 0; i < n_buffers; ++i) + v4l2_munmap(buffers[i].start, buffers[i].length); + v4l2_close(fd); + + return 0; +} + diff --git a/Documentation/DocBook/media/v4l/vbi_525.gif b/Documentation/DocBook/media/v4l/vbi_525.gif new file mode 100644 index 00000000000..5580b690d50 Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_525.gif differ diff --git a/Documentation/DocBook/media/v4l/vbi_525.pdf b/Documentation/DocBook/media/v4l/vbi_525.pdf new file mode 100644 index 00000000000..9e72c25b208 Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_525.pdf differ diff --git a/Documentation/DocBook/media/v4l/vbi_625.gif b/Documentation/DocBook/media/v4l/vbi_625.gif new file mode 100644 index 00000000000..34e3251983c Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_625.gif differ diff --git a/Documentation/DocBook/media/v4l/vbi_625.pdf b/Documentation/DocBook/media/v4l/vbi_625.pdf new file mode 100644 index 00000000000..765235e33a4 Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_625.pdf differ diff --git a/Documentation/DocBook/media/v4l/vbi_hsync.gif b/Documentation/DocBook/media/v4l/vbi_hsync.gif new file mode 100644 index 00000000000..b02434d3b35 Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_hsync.gif differ diff --git a/Documentation/DocBook/media/v4l/vbi_hsync.pdf b/Documentation/DocBook/media/v4l/vbi_hsync.pdf new file mode 100644 index 00000000000..200b668189b Binary files /dev/null and b/Documentation/DocBook/media/v4l/vbi_hsync.pdf differ diff --git a/Documentation/DocBook/media/v4l/vidioc-cropcap.xml b/Documentation/DocBook/media/v4l/vidioc-cropcap.xml new file mode 100644 index 00000000000..816e90e283c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-cropcap.xml @@ -0,0 +1,174 @@ + + + ioctl VIDIOC_CROPCAP + &manvol; + + + + VIDIOC_CROPCAP + Information about the video cropping and scaling abilities + + + + + + int ioctl + int fd + int request + struct v4l2_cropcap +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_CROPCAP + + + + argp + + + + + + + + + Description + + Applications use this function to query the cropping +limits, the pixel aspect of images and to calculate scale factors. +They set the type field of a v4l2_cropcap +structure to the respective buffer (stream) type and call the +VIDIOC_CROPCAP ioctl with a pointer to this +structure. Drivers fill the rest of the structure. The results are +constant except when switching the video standard. Remember this +switch can occur implicit when switching the video input or +output. + + + struct <structname>v4l2_cropcap</structname> + + &cs-str; + + + &v4l2-buf-type; + type + Type of the data stream, set by the application. +Only these types are valid here: +V4L2_BUF_TYPE_VIDEO_CAPTURE, +V4L2_BUF_TYPE_VIDEO_OUTPUT, +V4L2_BUF_TYPE_VIDEO_OVERLAY, and custom (driver +defined) types with code V4L2_BUF_TYPE_PRIVATE +and higher. + + + struct v4l2_rect + bounds + Defines the window within capturing or output is +possible, this may exclude for example the horizontal and vertical +blanking areas. The cropping rectangle cannot exceed these limits. +Width and height are defined in pixels, the driver writer is free to +choose origin and units of the coordinate system in the analog +domain. + + + struct v4l2_rect + defrect + Default cropping rectangle, it shall cover the +"whole picture". Assuming pixel aspect 1/1 this could be for example a +640 × 480 rectangle for NTSC, a +768 × 576 rectangle for PAL and SECAM centered over +the active picture area. The same co-ordinate system as for + bounds is used. + + + &v4l2-fract; + pixelaspect + This is the pixel aspect (y / x) when no +scaling is applied, the ratio of the actual sampling +frequency and the frequency required to get square +pixels.When cropping coordinates refer to square pixels, +the driver sets pixelaspect to 1/1. Other +common values are 54/59 for PAL and SECAM, 11/10 for NTSC sampled +according to []. + + + +
+ + + + + struct <structname>v4l2_rect</structname> + + &cs-str; + + + __s32 + left + Horizontal offset of the top, left corner of the +rectangle, in pixels. + + + __s32 + top + Vertical offset of the top, left corner of the +rectangle, in pixels. + + + __s32 + width + Width of the rectangle, in pixels. + + + __s32 + height + Height of the rectangle, in pixels. Width +and height cannot be negative, the fields are signed for +hysterical reasons. + + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-cropcap; type is +invalid or the ioctl is not supported. This is not permitted for +video capture, output and overlay devices, which must support +VIDIOC_CROPCAP. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml new file mode 100644 index 00000000000..4a09e203af0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml @@ -0,0 +1,275 @@ + + + ioctl VIDIOC_DBG_G_CHIP_IDENT + &manvol; + + + + VIDIOC_DBG_G_CHIP_IDENT + Identify the chips on a TV card + + + + + + int ioctl + int fd + int request + struct v4l2_dbg_chip_ident +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_DBG_G_CHIP_IDENT + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental interface and may change in +the future. + + + For driver debugging purposes this ioctl allows test +applications to query the driver about the chips present on the TV +card. Regular applications must not use it. When you found a chip +specific bug, please contact the linux-media mailing list (&v4l-ml;) +so it can be fixed. + + To query the driver applications must initialize the +match.type and +match.addr or match.name +fields of a &v4l2-dbg-chip-ident; +and call VIDIOC_DBG_G_CHIP_IDENT with a pointer to +this structure. On success the driver stores information about the +selected chip in the ident and +revision fields. On failure the structure +remains unchanged. + + When match.type is +V4L2_CHIP_MATCH_HOST, +match.addr selects the nth non-&i2c; chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing match.addr by one until +VIDIOC_DBG_G_CHIP_IDENT fails with an &EINVAL;. +The number zero always selects the host chip, ⪚ the chip connected +to the PCI or USB bus. + + When match.type is +V4L2_CHIP_MATCH_I2C_DRIVER, +match.name contains the I2C driver name. +For instance +"saa7127" will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +ioctl will return V4L2_IDENT_AMBIGUOUS in the +ident field. + + When match.type is +V4L2_CHIP_MATCH_I2C_ADDR, +match.addr selects a chip by its 7 bit +&i2c; bus address. + + When match.type is +V4L2_CHIP_MATCH_AC97, +match.addr selects the nth AC97 chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing match.addr by one until +VIDIOC_DBG_G_CHIP_IDENT fails with an &EINVAL;. + + On success, the ident field will +contain a chip ID from the Linux +media/v4l2-chip-ident.h header file, and the +revision field will contain a driver +specific value, or zero if no particular revision is associated with +this chip. + + When the driver could not identify the selected chip, +ident will contain +V4L2_IDENT_UNKNOWN. When no chip matched +the ioctl will succeed but the +ident field will contain +V4L2_IDENT_NONE. If multiple chips matched, +ident will contain +V4L2_IDENT_AMBIGUOUS. In all these cases the +revision field remains unchanged. + + This ioctl is optional, not all drivers may support it. It +was introduced in Linux 2.6.21, but the API was changed to the +one described here in 2.6.29. + + We recommended the v4l2-dbg +utility over calling this ioctl directly. It is available from the +LinuxTV v4l-dvb repository; see http://linuxtv.org/repo/ for +access instructions. + + + + struct <structname>v4l2_dbg_match</structname> + + &cs-ustr; + + + __u32 + type + See for a list of +possible types. + + + union + (anonymous) + + + + __u32 + addr + Match a chip by this number, interpreted according +to the type field. + + + + char + name[32] + Match a chip by this name, interpreted according +to the type field. + + + +
+ + + struct <structname>v4l2_dbg_chip_ident</structname> + + &cs-str; + + + struct v4l2_dbg_match + match + How to match the chip, see . + + + __u32 + ident + A chip identifier as defined in the Linux +media/v4l2-chip-ident.h header file, or one of +the values from . + + + __u32 + revision + A chip revision, chip and driver specific. + + + +
+ + + + Chip Match Types + + &cs-def; + + + V4L2_CHIP_MATCH_HOST + 0 + Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips. + + + V4L2_CHIP_MATCH_I2C_DRIVER + 1 + Match an &i2c; chip by its driver name. + + + V4L2_CHIP_MATCH_I2C_ADDR + 2 + Match a chip by its 7 bit &i2c; bus address. + + + V4L2_CHIP_MATCH_AC97 + 3 + Match the nth anciliary AC97 chip. + + + +
+ + + + Chip Identifiers + + &cs-def; + + + V4L2_IDENT_NONE + 0 + No chip matched. + + + V4L2_IDENT_AMBIGUOUS + 1 + Multiple chips matched. + + + V4L2_IDENT_UNKNOWN + 2 + A chip is present at this address, but the driver +could not identify it. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl, or the +match_type is invalid. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml new file mode 100644 index 00000000000..980c7f3e2fd --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml @@ -0,0 +1,275 @@ + + + ioctl VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER + &manvol; + + + + VIDIOC_DBG_G_REGISTER + VIDIOC_DBG_S_REGISTER + Read or write hardware registers + + + + + + int ioctl + int fd + int request + struct v4l2_dbg_register *argp + + + + + int ioctl + int fd + int request + const struct v4l2_dbg_register +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + For driver debugging purposes these ioctls allow test +applications to access hardware registers directly. Regular +applications must not use them. + + Since writing or even reading registers can jeopardize the +system security, its stability and damage the hardware, both ioctls +require superuser privileges. Additionally the Linux kernel must be +compiled with the CONFIG_VIDEO_ADV_DEBUG option +to enable these ioctls. + + To write a register applications must initialize all fields +of a &v4l2-dbg-register; and call +VIDIOC_DBG_S_REGISTER with a pointer to this +structure. The match.type and +match.addr or match.name +fields select a chip on the TV +card, the reg field specifies a register +number and the val field the value to be +written into the register. + + To read a register applications must initialize the +match.type, +match.chip or match.name and +reg fields, and call +VIDIOC_DBG_G_REGISTER with a pointer to this +structure. On success the driver stores the register value in the +val field. On failure the structure remains +unchanged. + + When match.type is +V4L2_CHIP_MATCH_HOST, +match.addr selects the nth non-&i2c; chip +on the TV card. The number zero always selects the host chip, ⪚ the +chip connected to the PCI or USB bus. You can find out which chips are +present with the &VIDIOC-DBG-G-CHIP-IDENT; ioctl. + + When match.type is +V4L2_CHIP_MATCH_I2C_DRIVER, +match.name contains the I2C driver name. +For instance +"saa7127" will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +effect of these ioctls is undefined. Again with the +&VIDIOC-DBG-G-CHIP-IDENT; ioctl you can find out which &i2c; chips are +present. + + When match.type is +V4L2_CHIP_MATCH_I2C_ADDR, +match.addr selects a chip by its 7 bit &i2c; +bus address. + + When match.type is +V4L2_CHIP_MATCH_AC97, +match.addr selects the nth AC97 chip +on the TV card. + + + Success not guaranteed + + Due to a flaw in the Linux &i2c; bus driver these ioctls may +return successfully without actually reading or writing a register. To +catch the most likely failure we recommend a &VIDIOC-DBG-G-CHIP-IDENT; +call confirming the presence of the selected &i2c; chip. + + + These ioctls are optional, not all drivers may support them. +However when a driver supports these ioctls it must also support +&VIDIOC-DBG-G-CHIP-IDENT;. Conversely it may support +VIDIOC_DBG_G_CHIP_IDENT but not these ioctls. + + VIDIOC_DBG_G_REGISTER and +VIDIOC_DBG_S_REGISTER were introduced in Linux +2.6.21, but their API was changed to the one described here in kernel 2.6.29. + + We recommended the v4l2-dbg +utility over calling these ioctls directly. It is available from the +LinuxTV v4l-dvb repository; see http://linuxtv.org/repo/ for +access instructions. + + + + struct <structname>v4l2_dbg_match</structname> + + &cs-ustr; + + + __u32 + type + See for a list of +possible types. + + + union + (anonymous) + + + + __u32 + addr + Match a chip by this number, interpreted according +to the type field. + + + + char + name[32] + Match a chip by this name, interpreted according +to the type field. + + + +
+ + + + struct <structname>v4l2_dbg_register</structname> + + + + + + + struct v4l2_dbg_match + match + How to match the chip, see . + + + __u64 + reg + A register number. + + + __u64 + val + The value read from, or to be written into the +register. + + + +
+ + + + Chip Match Types + + &cs-def; + + + V4L2_CHIP_MATCH_HOST + 0 + Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips. + + + V4L2_CHIP_MATCH_I2C_DRIVER + 1 + Match an &i2c; chip by its driver name. + + + V4L2_CHIP_MATCH_I2C_ADDR + 2 + Match a chip by its 7 bit &i2c; bus address. + + + V4L2_CHIP_MATCH_AC97 + 3 + Match the nth anciliary AC97 chip. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl, or the kernel +was not compiled with the CONFIG_VIDEO_ADV_DEBUG +option, or the match_type is invalid, or the +selected chip or register does not exist. + + + + EPERM + + Insufficient permissions. Root privileges are required +to execute these ioctls. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml new file mode 100644 index 00000000000..4e0a7cc3081 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -0,0 +1,131 @@ + + + ioctl VIDIOC_DQEVENT + &manvol; + + + + VIDIOC_DQEVENT + Dequeue event + + + + + + int ioctl + int fd + int request + struct v4l2_event +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_DQEVENT + + + + argp + + + + + + + + + Description + + Dequeue an event from a video device. No input is required + for this ioctl. All the fields of the &v4l2-event; structure are + filled by the driver. The file handle will also receive exceptions + which the application may get by e.g. using the select system + call. + + + struct <structname>v4l2_event</structname> + + &cs-str; + + + __u32 + type + + Type of the event. + + + union + u + + + + + + &v4l2-event-vsync; + vsync + Event data for event V4L2_EVENT_VSYNC. + + + + + __u8 + data[64] + Event data. Defined by the event type. The union + should be used to define easily accessible type for + events. + + + __u32 + pending + + Number of pending events excluding this one. + + + __u32 + sequence + + Event sequence number. The sequence number is + incremented for every subscribed event that takes place. + If sequence numbers are not contiguous it means that + events have been lost. + + + + struct timespec + timestamp + + Event timestamp. + + + __u32 + reserved[9] + + Reserved for future extensions. Drivers must set + the array to zero. + + + +
+ + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml new file mode 100644 index 00000000000..b0dde943825 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml @@ -0,0 +1,204 @@ + + + ioctl VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD + &manvol; + + + + VIDIOC_ENCODER_CMD + VIDIOC_TRY_ENCODER_CMD + Execute an encoder command + + + + + + int ioctl + int fd + int request + struct v4l2_encoder_cmd *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + These ioctls control an audio/video (usually MPEG-) encoder. +VIDIOC_ENCODER_CMD sends a command to the +encoder, VIDIOC_TRY_ENCODER_CMD can be used to +try a command without actually executing it. + + To send a command applications must initialize all fields of a + &v4l2-encoder-cmd; and call + VIDIOC_ENCODER_CMD or + VIDIOC_TRY_ENCODER_CMD with a pointer to this + structure. + + The cmd field must contain the +command code. The flags field is currently +only used by the STOP command and contains one bit: If the +V4L2_ENC_CMD_STOP_AT_GOP_END flag is set, +encoding will continue until the end of the current Group +Of Pictures, otherwise it will stop immediately. + + A read() call sends a START command to +the encoder if it has not been started yet. After a STOP command, +read() calls will read the remaining data +buffered by the driver. When the buffer is empty, +read() will return zero and the next +read() call will restart the encoder. + + A close() call sends an immediate STOP +to the encoder, and all buffered data is discarded. + + These ioctls are optional, not all drivers may support +them. They were introduced in Linux 2.6.21. + + + struct <structname>v4l2_encoder_cmd</structname> + + &cs-str; + + + __u32 + cmd + The encoder command, see . + + + __u32 + flags + Flags to go with the command, see . If no flags are defined for +this command, drivers and applications must set this field to +zero. + + + __u32 + data[8] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Encoder Commands + + &cs-def; + + + V4L2_ENC_CMD_START + 0 + Start the encoder. When the encoder is already +running or paused, this command does nothing. No flags are defined for +this command. + + + V4L2_ENC_CMD_STOP + 1 + Stop the encoder. When the +V4L2_ENC_CMD_STOP_AT_GOP_END flag is set, +encoding will continue until the end of the current Group +Of Pictures, otherwise encoding will stop immediately. +When the encoder is already stopped, this command does +nothing. + + + V4L2_ENC_CMD_PAUSE + 2 + Pause the encoder. When the encoder has not been +started yet, the driver will return an &EPERM;. When the encoder is +already paused, this command does nothing. No flags are defined for +this command. + + + V4L2_ENC_CMD_RESUME + 3 + Resume encoding after a PAUSE command. When the +encoder has not been started yet, the driver will return an &EPERM;. +When the encoder is already running, this command does nothing. No +flags are defined for this command. + + + +
+ + + Encoder Command Flags + + &cs-def; + + + V4L2_ENC_CMD_STOP_AT_GOP_END + 0x0001 + Stop encoding at the end of the current Group Of +Pictures, rather than immediately. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl, or the +cmd field is invalid. + + + + EPERM + + The application sent a PAUSE or RESUME command when +the encoder was not running. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml b/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml new file mode 100644 index 00000000000..1d31427edd1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml @@ -0,0 +1,238 @@ + + + ioctl VIDIOC_ENUM_DV_PRESETS + &manvol; + + + + VIDIOC_ENUM_DV_PRESETS + Enumerate supported Digital Video presets + + + + + + int ioctl + int fd + int request + struct v4l2_dv_enum_preset *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_DV_PRESETS + + + + argp + + + + + + + + + Description + + To query the attributes of a DV preset, applications initialize the +index field and zero the reserved array of &v4l2-dv-enum-preset; +and call the VIDIOC_ENUM_DV_PRESETS ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all DV Presets supported, +applications shall begin at index zero, incrementing by one until the +driver returns EINVAL. Drivers may enumerate a +different set of DV presets after switching the video input or +output. + + + struct <structname>v4l2_dv_enum_presets</structname> + + &cs-str; + + + __u32 + index + Number of the DV preset, set by the +application. + + + __u32 + preset + This field identifies one of the DV preset values listed in . + + + __u8 + name[24] + Name of the preset, a NUL-terminated ASCII string, for example: "720P-60", "1080I-60". This information is +intended for the user. + + + __u32 + width + Width of the active video in pixels for the DV preset. + + + __u32 + height + Height of the active video in lines for the DV preset. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers must set the array to zero. + + + +
+ + + struct <structname>DV Presets</structname> + + &cs-str; + + + Preset + Preset value + Description + + + + + + + + V4L2_DV_INVALID + 0 + Invalid preset value. + + + V4L2_DV_480P59_94 + 1 + 720x480 progressive video at 59.94 fps as per BT.1362. + + + V4L2_DV_576P50 + 2 + 720x576 progressive video at 50 fps as per BT.1362. + + + V4L2_DV_720P24 + 3 + 1280x720 progressive video at 24 fps as per SMPTE 296M. + + + V4L2_DV_720P25 + 4 + 1280x720 progressive video at 25 fps as per SMPTE 296M. + + + V4L2_DV_720P30 + 5 + 1280x720 progressive video at 30 fps as per SMPTE 296M. + + + V4L2_DV_720P50 + 6 + 1280x720 progressive video at 50 fps as per SMPTE 296M. + + + V4L2_DV_720P59_94 + 7 + 1280x720 progressive video at 59.94 fps as per SMPTE 274M. + + + V4L2_DV_720P60 + 8 + 1280x720 progressive video at 60 fps as per SMPTE 274M/296M. + + + V4L2_DV_1080I29_97 + 9 + 1920x1080 interlaced video at 29.97 fps as per BT.1120/SMPTE 274M. + + + V4L2_DV_1080I30 + 10 + 1920x1080 interlaced video at 30 fps as per BT.1120/SMPTE 274M. + + + V4L2_DV_1080I25 + 11 + 1920x1080 interlaced video at 25 fps as per BT.1120. + + + V4L2_DV_1080I50 + 12 + 1920x1080 interlaced video at 50 fps as per SMPTE 296M. + + + V4L2_DV_1080I60 + 13 + 1920x1080 interlaced video at 60 fps as per SMPTE 296M. + + + V4L2_DV_1080P24 + 14 + 1920x1080 progressive video at 24 fps as per SMPTE 296M. + + + V4L2_DV_1080P25 + 15 + 1920x1080 progressive video at 25 fps as per SMPTE 296M. + + + V4L2_DV_1080P30 + 16 + 1920x1080 progressive video at 30 fps as per SMPTE 296M. + + + V4L2_DV_1080P50 + 17 + 1920x1080 progressive video at 50 fps as per BT.1120. + + + V4L2_DV_1080P60 + 18 + 1920x1080 progressive video at 60 fps as per BT.1120. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-dv-enum-preset; index +is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml new file mode 100644 index 00000000000..71d373b6d36 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml @@ -0,0 +1,166 @@ + + + ioctl VIDIOC_ENUM_FMT + &manvol; + + + + VIDIOC_ENUM_FMT + Enumerate image formats + + + + + + int ioctl + int fd + int request + struct v4l2_fmtdesc +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_FMT + + + + argp + + + + + + + + + Description + + To enumerate image formats applications initialize the +type and index +field of &v4l2-fmtdesc; and call the +VIDIOC_ENUM_FMT ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL;. All formats are enumerable by beginning at index zero and +incrementing by one until EINVAL is +returned. + + + struct <structname>v4l2_fmtdesc</structname> + + &cs-str; + + + __u32 + index + Number of the format in the enumeration, set by +the application. This is in no way related to the +pixelformat field. + + + &v4l2-buf-type; + type + Type of the data stream, set by the application. +Only these types are valid here: +V4L2_BUF_TYPE_VIDEO_CAPTURE, +V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, +V4L2_BUF_TYPE_VIDEO_OUTPUT, +V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, +V4L2_BUF_TYPE_VIDEO_OVERLAY, and custom (driver +defined) types with code V4L2_BUF_TYPE_PRIVATE +and higher. + + + __u32 + flags + See + + + __u8 + description[32] + Description of the format, a NUL-terminated ASCII +string. This information is intended for the user, for example: "YUV +4:2:2". + + + __u32 + pixelformat + The image format identifier. This is a +four character code as computed by the v4l2_fourcc() +macro: + + + +#define v4l2_fourcc(a,b,c,d) (((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24)) +Several image formats are already +defined by this specification in . Note these +codes are not the same as those used in the Windows world. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + Image Format Description Flags + + &cs-def; + + + V4L2_FMT_FLAG_COMPRESSED + 0x0001 + This is a compressed format. + + + V4L2_FMT_FLAG_EMULATED + 0x0002 + This format is not native to the device but emulated +through software (usually libv4l2), where possible try to use a native format +instead for better performance. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-fmtdesc; type +is not supported or the index is out of +bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml new file mode 100644 index 00000000000..3c216e113a5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml @@ -0,0 +1,270 @@ + + + + ioctl VIDIOC_ENUM_FRAMEINTERVALS + &manvol; + + + + VIDIOC_ENUM_FRAMEINTERVALS + Enumerate frame intervals + + + + + + int ioctl + int fd + int request + struct v4l2_frmivalenum *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_FRAMEINTERVALS + + + + argp + + Pointer to a &v4l2-frmivalenum; structure that +contains a pixel format and size and receives a frame interval. + + + + + + + Description + + This ioctl allows applications to enumerate all frame +intervals that the device supports for the given pixel format and +frame size. + The supported pixel formats and frame sizes can be obtained +by using the &VIDIOC-ENUM-FMT; and &VIDIOC-ENUM-FRAMESIZES; +functions. + The return value and the content of the +v4l2_frmivalenum.type field depend on the +type of frame intervals the device supports. Here are the semantics of +the function for the different cases: + + + Discrete: The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +EINVAL is returned. The `v4l2_frmivalenum.type` +field is set to `V4L2_FRMIVAL_TYPE_DISCRETE` by the driver. Of the +union only the `discrete` member is valid. + + + Step-wise: The function +returns success if the given index value is zero and +EINVAL for any other index value. The +v4l2_frmivalenum.type field is set to +V4L2_FRMIVAL_TYPE_STEPWISE by the driver. Of the +union only the stepwise member is +valid. + + + Continuous: This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and EINVAL for +any other index value. The +v4l2_frmivalenum.type field is set to +V4L2_FRMIVAL_TYPE_CONTINUOUS by the driver. Of +the union only the stepwise member is valid +and the step value is set to 1. + + + + When the application calls the function with index zero, it +must check the type field to determine the +type of frame interval enumeration the device supports. Only for the +V4L2_FRMIVAL_TYPE_DISCRETE type does it make +sense to increase the index value to receive more frame +intervals. + Note that the order in which the frame intervals are +returned has no special meaning. In particular does it not say +anything about potential default frame intervals. + Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame interval +enumeration. + + + + Notes + + + + Frame intervals and frame +rates: The V4L2 API uses frame intervals instead of frame +rates. Given the frame interval the frame rate can be computed as +follows:frame_rate = 1 / frame_interval + + + + + + + Structs + + In the structs below, IN denotes a +value that has to be filled in by the application, +OUT denotes values that the driver fills in. The +application should zero out all members except for the +IN fields. + + + struct <structname>v4l2_frmival_stepwise</structname> + + &cs-str; + + + &v4l2-fract; + min + Minimum frame interval [s]. + + + &v4l2-fract; + max + Maximum frame interval [s]. + + + &v4l2-fract; + step + Frame interval step size [s]. + + + +
+ + + struct <structname>v4l2_frmivalenum</structname> + + + + + + + + __u32 + index + + IN: Index of the given frame interval in the +enumeration. + + + __u32 + pixel_format + + IN: Pixel format for which the frame intervals are +enumerated. + + + __u32 + width + + IN: Frame width for which the frame intervals are +enumerated. + + + __u32 + height + + IN: Frame height for which the frame intervals are +enumerated. + + + __u32 + type + + OUT: Frame interval type the device supports. + + + union + + + OUT: Frame interval with the given index. + + + + &v4l2-fract; + discrete + Frame interval [s]. + + + + &v4l2-frmival-stepwise; + stepwise + + + + __u32 + reserved[2] + + Reserved space for future use. + + + +
+ + + + Enums + + + enum <structname>v4l2_frmivaltypes</structname> + + &cs-def; + + + V4L2_FRMIVAL_TYPE_DISCRETE + 1 + Discrete frame interval. + + + V4L2_FRMIVAL_TYPE_CONTINUOUS + 2 + Continuous frame interval. + + + V4L2_FRMIVAL_TYPE_STEPWISE + 3 + Step-wise defined frame interval. + + + +
+ + + + &return-value; + + See the description section above for a list of return +values that errno can have. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml new file mode 100644 index 00000000000..6afa4542c81 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml @@ -0,0 +1,282 @@ + + + + ioctl VIDIOC_ENUM_FRAMESIZES + &manvol; + + + + VIDIOC_ENUM_FRAMESIZES + Enumerate frame sizes + + + + + + int ioctl + int fd + int request + struct v4l2_frmsizeenum *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUM_FRAMESIZES + + + + argp + + Pointer to a &v4l2-frmsizeenum; that contains an index +and pixel format and receives a frame width and height. + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + This ioctl allows applications to enumerate all frame sizes +(&ie; width and height in pixels) that the device supports for the +given pixel format. + The supported pixel formats can be obtained by using the +&VIDIOC-ENUM-FMT; function. + The return value and the content of the +v4l2_frmsizeenum.type field depend on the +type of frame sizes the device supports. Here are the semantics of the +function for the different cases: + + + + Discrete: The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +EINVAL is returned. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_DISCRETE by the driver. Of the +union only the discrete member is +valid. + + + Step-wise: The function +returns success if the given index value is zero and +EINVAL for any other index value. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_STEPWISE by the driver. Of the +union only the stepwise member is +valid. + + + Continuous: This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and EINVAL for +any other index value. The +v4l2_frmsizeenum.type field is set to +V4L2_FRMSIZE_TYPE_CONTINUOUS by the driver. Of +the union only the stepwise member is valid +and the step_width and +step_height values are set to 1. + + + + When the application calls the function with index zero, it +must check the type field to determine the +type of frame size enumeration the device supports. Only for the +V4L2_FRMSIZE_TYPE_DISCRETE type does it make +sense to increase the index value to receive more frame sizes. + Note that the order in which the frame sizes are returned +has no special meaning. In particular does it not say anything about +potential default format sizes. + Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame size +enumeration. + + + + Structs + + In the structs below, IN denotes a +value that has to be filled in by the application, +OUT denotes values that the driver fills in. The +application should zero out all members except for the +IN fields. + + + struct <structname>v4l2_frmsize_discrete</structname> + + &cs-str; + + + __u32 + width + Width of the frame [pixel]. + + + __u32 + height + Height of the frame [pixel]. + + + +
+ + + struct <structname>v4l2_frmsize_stepwise</structname> + + &cs-str; + + + __u32 + min_width + Minimum frame width [pixel]. + + + __u32 + max_width + Maximum frame width [pixel]. + + + __u32 + step_width + Frame width step size [pixel]. + + + __u32 + min_height + Minimum frame height [pixel]. + + + __u32 + max_height + Maximum frame height [pixel]. + + + __u32 + step_height + Frame height step size [pixel]. + + + +
+ + + struct <structname>v4l2_frmsizeenum</structname> + + + + + + + + __u32 + index + + IN: Index of the given frame size in the enumeration. + + + __u32 + pixel_format + + IN: Pixel format for which the frame sizes are enumerated. + + + __u32 + type + + OUT: Frame size type the device supports. + + + union + + + OUT: Frame size with the given index. + + + + &v4l2-frmsize-discrete; + discrete + + + + + &v4l2-frmsize-stepwise; + stepwise + + + + __u32 + reserved[2] + + Reserved space for future use. + + + +
+ + + + Enums + + + enum <structname>v4l2_frmsizetypes</structname> + + &cs-def; + + + V4L2_FRMSIZE_TYPE_DISCRETE + 1 + Discrete frame size. + + + V4L2_FRMSIZE_TYPE_CONTINUOUS + 2 + Continuous frame size. + + + V4L2_FRMSIZE_TYPE_STEPWISE + 3 + Step-wise defined frame size. + + + +
+ + + + &return-value; + + See the description section above for a list of return +values that errno can have. + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml new file mode 100644 index 00000000000..9ae8f2d3a96 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml @@ -0,0 +1,86 @@ + + + ioctl VIDIOC_ENUMAUDIO + &manvol; + + + + VIDIOC_ENUMAUDIO + Enumerate audio inputs + + + + + + int ioctl + int fd + int request + struct v4l2_audio *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUMAUDIO + + + + argp + + + + + + + + + Description + + To query the attributes of an audio input applications +initialize the index field and zero out the +reserved array of a &v4l2-audio; +and call the VIDIOC_ENUMAUDIO ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +inputs applications shall begin at index zero, incrementing by one +until the driver returns EINVAL. + + See for a description of +&v4l2-audio;. + + + + &return-value; + + + + EINVAL + + The number of the audio input is out of bounds, or +there are no audio inputs at all and this ioctl is not +supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml new file mode 100644 index 00000000000..d3d7c0ab17b --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml @@ -0,0 +1,89 @@ + + + ioctl VIDIOC_ENUMAUDOUT + &manvol; + + + + VIDIOC_ENUMAUDOUT + Enumerate audio outputs + + + + + + int ioctl + int fd + int request + struct v4l2_audioout *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUMAUDOUT + + + + argp + + + + + + + + + Description + + To query the attributes of an audio output applications +initialize the index field and zero out the +reserved array of a &v4l2-audioout; and +call the VIDIOC_G_AUDOUT ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +outputs applications shall begin at index zero, incrementing by one +until the driver returns EINVAL. + + Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense. + + See for a description of +&v4l2-audioout;. + + + + &return-value; + + + + EINVAL + + The number of the audio output is out of bounds, or +there are no audio outputs at all and this ioctl is not +supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enuminput.xml b/Documentation/DocBook/media/v4l/vidioc-enuminput.xml new file mode 100644 index 00000000000..476fe1d2bba --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enuminput.xml @@ -0,0 +1,321 @@ + + + ioctl VIDIOC_ENUMINPUT + &manvol; + + + + VIDIOC_ENUMINPUT + Enumerate video inputs + + + + + + int ioctl + int fd + int request + struct v4l2_input +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUMINPUT + + + + argp + + + + + + + + + Description + + To query the attributes of a video input applications +initialize the index field of &v4l2-input; +and call the VIDIOC_ENUMINPUT ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +inputs applications shall begin at index zero, incrementing by one +until the driver returns EINVAL. + + + struct <structname>v4l2_input</structname> + + &cs-str; + + + __u32 + index + Identifies the input, set by the +application. + + + __u8 + name[32] + Name of the video input, a NUL-terminated ASCII +string, for example: "Vin (Composite 2)". This information is intended +for the user, preferably the connector label on the device itself. + + + __u32 + type + Type of the input, see . + + + __u32 + audioset + Drivers can enumerate up to 32 video and +audio inputs. This field shows which audio inputs were selectable as +audio source if this was the currently selected video input. It is a +bit mask. The LSB corresponds to audio input 0, the MSB to input 31. +Any number of bits can be set, or none.When the driver +does not enumerate audio inputs no bits must be set. Applications +shall not interpret this as lack of audio support. Some drivers +automatically select audio sources and do not enumerate them since +there is no choice anyway.For details on audio inputs and +how to select the current input see . + + + __u32 + tuner + Capture devices can have zero or more tuners (RF +demodulators). When the type is set to +V4L2_INPUT_TYPE_TUNER this is an RF connector and +this field identifies the tuner. It corresponds to +&v4l2-tuner; field index. For details on +tuners see . + + + &v4l2-std-id; + std + Every video input supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see . + + + __u32 + status + This field provides status information about the +input. See for flags. +With the exception of the sensor orientation bits status is only valid when this is the +current input. + + + __u32 + capabilities + This field provides capabilities for the +input. See for flags. + + + __u32 + reserved[3] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + Input Types + + &cs-def; + + + V4L2_INPUT_TYPE_TUNER + 1 + This input uses a tuner (RF demodulator). + + + V4L2_INPUT_TYPE_CAMERA + 2 + Analog baseband input, for example CVBS / +Composite Video, S-Video, RGB. + + + +
+ + + + + Input Status Flags + + + + + + + + General + + + V4L2_IN_ST_NO_POWER + 0x00000001 + Attached device is off. + + + V4L2_IN_ST_NO_SIGNAL + 0x00000002 + + + + V4L2_IN_ST_NO_COLOR + 0x00000004 + The hardware supports color decoding, but does not +detect color modulation in the signal. + + + Sensor Orientation + + + V4L2_IN_ST_HFLIP + 0x00000010 + The input is connected to a device that produces a signal +that is flipped horizontally and does not correct this before passing the +signal to userspace. + + + V4L2_IN_ST_VFLIP + 0x00000020 + The input is connected to a device that produces a signal +that is flipped vertically and does not correct this before passing the +signal to userspace. Note that a 180 degree rotation is the same as HFLIP | VFLIP + + + Analog Video + + + V4L2_IN_ST_NO_H_LOCK + 0x00000100 + No horizontal sync lock. + + + V4L2_IN_ST_COLOR_KILL + 0x00000200 + A color killer circuit automatically disables color +decoding when it detects no color modulation. When this flag is set +the color killer is enabled and has shut off +color decoding. + + + Digital Video + + + V4L2_IN_ST_NO_SYNC + 0x00010000 + No synchronization lock. + + + V4L2_IN_ST_NO_EQU + 0x00020000 + No equalizer lock. + + + V4L2_IN_ST_NO_CARRIER + 0x00040000 + Carrier recovery failed. + + + VCR and Set-Top Box + + + V4L2_IN_ST_MACROVISION + 0x01000000 + Macrovision is an analog copy prevention system +mangling the video signal to confuse video recorders. When this +flag is set Macrovision has been detected. + + + V4L2_IN_ST_NO_ACCESS + 0x02000000 + Conditional access denied. + + + V4L2_IN_ST_VTR + 0x04000000 + VTR time constant. [?] + + + +
+ + + + Input capabilities + + &cs-def; + + + V4L2_IN_CAP_PRESETS + 0x00000001 + This input supports setting DV presets by using VIDIOC_S_DV_PRESET. + + + V4L2_IN_CAP_CUSTOM_TIMINGS + 0x00000002 + This input supports setting custom video timings by using VIDIOC_S_DV_TIMINGS. + + + V4L2_IN_CAP_STD + 0x00000004 + This input supports setting the TV standard by using VIDIOC_S_STD. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-input; index is +out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml b/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml new file mode 100644 index 00000000000..a281d26a195 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumoutput.xml @@ -0,0 +1,206 @@ + + + ioctl VIDIOC_ENUMOUTPUT + &manvol; + + + + VIDIOC_ENUMOUTPUT + Enumerate video outputs + + + + + + int ioctl + int fd + int request + struct v4l2_output *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUMOUTPUT + + + + argp + + + + + + + + + Description + + To query the attributes of a video outputs applications +initialize the index field of &v4l2-output; +and call the VIDIOC_ENUMOUTPUT ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +outputs applications shall begin at index zero, incrementing by one +until the driver returns EINVAL. + + + struct <structname>v4l2_output</structname> + + &cs-str; + + + __u32 + index + Identifies the output, set by the +application. + + + __u8 + name[32] + Name of the video output, a NUL-terminated ASCII +string, for example: "Vout". This information is intended for the +user, preferably the connector label on the device itself. + + + __u32 + type + Type of the output, see . + + + __u32 + audioset + Drivers can enumerate up to 32 video and +audio outputs. This field shows which audio outputs were +selectable as the current output if this was the currently selected +video output. It is a bit mask. The LSB corresponds to audio output 0, +the MSB to output 31. Any number of bits can be set, or +none.When the driver does not enumerate audio outputs no +bits must be set. Applications shall not interpret this as lack of +audio support. Drivers may automatically select audio outputs without +enumerating them.For details on audio outputs and how to +select the current output see . + + + __u32 + modulator + Output devices can have zero or more RF modulators. +When the type is +V4L2_OUTPUT_TYPE_MODULATOR this is an RF +connector and this field identifies the modulator. It corresponds to +&v4l2-modulator; field index. For details +on modulators see . + + + &v4l2-std-id; + std + Every video output supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see . + + + __u32 + capabilities + This field provides capabilities for the +output. See for flags. + + + __u32 + reserved[3] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + Output Type + + &cs-def; + + + V4L2_OUTPUT_TYPE_MODULATOR + 1 + This output is an analog TV modulator. + + + V4L2_OUTPUT_TYPE_ANALOG + 2 + Analog baseband output, for example Composite / +CVBS, S-Video, RGB. + + + V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY + 3 + [?] + + + +
+ + + + Output capabilities + + &cs-def; + + + V4L2_OUT_CAP_PRESETS + 0x00000001 + This output supports setting DV presets by using VIDIOC_S_DV_PRESET. + + + V4L2_OUT_CAP_CUSTOM_TIMINGS + 0x00000002 + This output supports setting custom video timings by using VIDIOC_S_DV_TIMINGS. + + + V4L2_OUT_CAP_STD + 0x00000004 + This output supports setting the TV standard by using VIDIOC_S_STD. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-output; index +is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-enumstd.xml b/Documentation/DocBook/media/v4l/vidioc-enumstd.xml new file mode 100644 index 00000000000..95803fe2c8e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enumstd.xml @@ -0,0 +1,391 @@ + + + ioctl VIDIOC_ENUMSTD + &manvol; + + + + VIDIOC_ENUMSTD + Enumerate supported video standards + + + + + + int ioctl + int fd + int request + struct v4l2_standard *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENUMSTD + + + + argp + + + + + + + + + Description + + To query the attributes of a video standard, +especially a custom (driver defined) one, applications initialize the +index field of &v4l2-standard; and call the +VIDIOC_ENUMSTD ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all standards +applications shall begin at index zero, incrementing by one until the +driver returns EINVAL. Drivers may enumerate a +different set of standards after switching the video input or +output. + The supported standards may overlap and we need an +unambiguous set to find the current standard returned by +VIDIOC_G_STD. + + + + struct <structname>v4l2_standard</structname> + + &cs-str; + + + __u32 + index + Number of the video standard, set by the +application. + + + &v4l2-std-id; + id + The bits in this field identify the standard as +one of the common standards listed in , +or if bits 32 to 63 are set as custom standards. Multiple bits can be +set if the hardware does not distinguish between these standards, +however separate indices do not indicate the opposite. The +id must be unique. No other enumerated +v4l2_standard structure, for this input or +output anyway, can contain the same set of bits. + + + __u8 + name[24] + Name of the standard, a NUL-terminated ASCII +string, for example: "PAL-B/G", "NTSC Japan". This information is +intended for the user. + + + &v4l2-fract; + frameperiod + The frame period (not field period) is numerator +/ denominator. For example M/NTSC has a frame period of 1001 / +30000 seconds. + + + __u32 + framelines + Total lines per frame including blanking, +e. g. 625 for B/PAL. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + struct <structname>v4l2_fract</structname> + + &cs-str; + + + __u32 + numerator + + + + __u32 + denominator + + + + +
+ + + typedef <structname>v4l2_std_id</structname> + + &cs-str; + + + __u64 + v4l2_std_id + This type is a set, each bit representing another +video standard as listed below and in . The 32 most significant bits are reserved +for custom (driver defined) video standards. + + + +
+ + +#define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) +#define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) +#define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) +#define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) +#define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) +#define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) +#define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) +#define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) + +#define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) +#define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) +#define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) +#define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) +V4L2_STD_PAL_60 is +a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color +modulation with a 4.43 MHz color subcarrier. Some PAL video recorders +can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic +PAL TV. +#define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) +#define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) +#define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) +V4L2_STD_NTSC_443 +is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC +color modulation with a 4.43 MHz color +subcarrier. +#define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) + +#define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) +#define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) +#define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) +#define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) +#define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) +#define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) +#define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) +#define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) + +/* ATSC/HDTV */ +#define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) +#define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) +V4L2_STD_ATSC_8_VSB and +V4L2_STD_ATSC_16_VSB are U.S. terrestrial digital +TV standards. Presently the V4L2 API does not support digital TV. See +also the Linux DVB API at http://linuxtv.org. + +#define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_PAL_G) +#define V4L2_STD_B (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_SECAM_B) +#define V4L2_STD_GH (V4L2_STD_PAL_G |\ + V4L2_STD_PAL_H |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H) +#define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\ + V4L2_STD_PAL_D1 |\ + V4L2_STD_PAL_K) +#define V4L2_STD_PAL (V4L2_STD_PAL_BG |\ + V4L2_STD_PAL_DK |\ + V4L2_STD_PAL_H |\ + V4L2_STD_PAL_I) +#define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\ + V4L2_STD_NTSC_M_JP |\ + V4L2_STD_NTSC_M_KR) +#define V4L2_STD_MN (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_NTSC) +#define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\ + V4L2_STD_SECAM_K |\ + V4L2_STD_SECAM_K1) +#define V4L2_STD_DK (V4L2_STD_PAL_DK |\ + V4L2_STD_SECAM_DK) + +#define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H |\ + V4L2_STD_SECAM_DK |\ + V4L2_STD_SECAM_L |\ + V4L2_STD_SECAM_LC) + +#define V4L2_STD_525_60 (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_60 |\ + V4L2_STD_NTSC |\ + V4L2_STD_NTSC_443) +#define V4L2_STD_625_50 (V4L2_STD_PAL |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_SECAM) + +#define V4L2_STD_UNKNOWN 0 +#define V4L2_STD_ALL (V4L2_STD_525_60 |\ + V4L2_STD_625_50) + + + + Video Standards (based on [<xref linkend="itu470" />]) + + + + + + + + + + + + + + + + Characteristics + M/NTSCJapan uses a standard +similar to M/NTSC +(V4L2_STD_NTSC_M_JP). + M/PAL + N/PAL The values in +brackets apply to the combination N/PAL a.k.a. +NC used in Argentina +(V4L2_STD_PAL_Nc). + B, B1, G/PAL + D, D1, K/PAL + H/PAL + I/PAL + B, G/SECAM + D, K/SECAM + K1/SECAM + L/SECAM + + + + + Frame lines + 525 + 625 + + + Frame period (s) + 1001/30000 + 1/25 + + + Chrominance sub-carrier frequency (Hz) + 3579545 ± 10 + 3579611.49 ± 10 + 4433618.75 ± 5 (3582056.25 +± 5) + 4433618.75 ± 5 + 4433618.75 ± 1 + fOR = +4406250 ± 2000, fOB = 4250000 +± 2000 + + + Nominal radio-frequency channel bandwidth +(MHz) + 6 + 6 + 6 + B: 7; B1, G: 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + + + Sound carrier relative to vision carrier +(MHz) + + 4.5 + + 4.5 + + 4.5 + + 5.5 ± 0.001 +In the Federal Republic of Germany, Austria, Italy, +the Netherlands, Slovakia and Switzerland a system of two sound +carriers is used, the frequency of the second carrier being +242.1875 kHz above the frequency of the first sound carrier. For +stereophonic sound transmissions a similar system is used in +Australia. New Zealand uses a sound +carrier displaced 5.4996 ± 0.0005 MHz from the vision +carrier. In Denmark, Finland, New +Zealand, Sweden and Spain a system of two sound carriers is used. In +Iceland, Norway and Poland the same system is being introduced. The +second carrier is 5.85 MHz above the vision carrier and is DQPSK +modulated with 728 kbit/s sound and data multiplex. (NICAM +system) In the United Kingdom, a +system of two sound carriers is used. The second sound carrier is +6.552 MHz above the vision carrier and is DQPSK modulated with a +728 kbit/s sound and data multiplex able to carry two sound +channels. (NICAM system) + + 6.5 ± 0.001 + + 5.5 + + 5.9996 ± 0.0005 + + 5.5 ± 0.001 + + 6.5 ± 0.001 + + 6.5 + + 6.5 In France, a +digital carrier 5.85 MHz away from the vision carrier may be used in +addition to the main sound carrier. It is modulated in differentially +encoded QPSK with a 728 kbit/s sound and data multiplexer capable of +carrying two sound channels. (NICAM +system) + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-standard; index +is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audio.xml b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml new file mode 100644 index 00000000000..65361a8c2b0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml @@ -0,0 +1,188 @@ + + + ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO + &manvol; + + + + VIDIOC_G_AUDIO + VIDIOC_S_AUDIO + Query or select the current audio input and its +attributes + + + + + + int ioctl + int fd + int request + struct v4l2_audio *argp + + + + + int ioctl + int fd + int request + const struct v4l2_audio *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_AUDIO, VIDIOC_S_AUDIO + + + + argp + + + + + + + + + Description + + To query the current audio input applications zero out the +reserved array of a &v4l2-audio; +and call the VIDIOC_G_AUDIO ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video input. + + Audio inputs have one writable property, the audio mode. To +select the current audio input and change the +audio mode, applications initialize the +index and mode +fields, and the +reserved array of a +v4l2_audio structure and call the +VIDIOC_S_AUDIO ioctl. Drivers may switch to a +different audio mode if the request cannot be satisfied. However, this +is a write-only ioctl, it does not return the actual new audio +mode. + + + struct <structname>v4l2_audio</structname> + + &cs-str; + + + __u32 + index + Identifies the audio input, set by the +driver or application. + + + __u8 + name[32] + Name of the audio input, a NUL-terminated ASCII +string, for example: "Line In". This information is intended for the +user, preferably the connector label on the device itself. + + + __u32 + capability + Audio capability flags, see . + + + __u32 + mode + Audio mode flags set by drivers and applications (on + VIDIOC_S_AUDIO ioctl), see . + + + __u32 + reserved[2] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Audio Capability Flags + + &cs-def; + + + V4L2_AUDCAP_STEREO + 0x00001 + This is a stereo input. The flag is intended to +automatically disable stereo recording etc. when the signal is always +monaural. The API provides no means to detect if stereo is +received, unless the audio input belongs to a +tuner. + + + V4L2_AUDCAP_AVL + 0x00002 + Automatic Volume Level mode is supported. + + + +
+ + + Audio Mode Flags + + &cs-def; + + + V4L2_AUDMODE_AVL + 0x00001 + AVL mode is on. + + + +
+ + + + &return-value; + + + + EINVAL + + No audio inputs combine with the current video input, +or the number of the selected audio input is out of bounds or it does +not combine, or there are no audio inputs at all and the ioctl is not +supported. + + + + EBUSY + + I/O is in progress, the input cannot be +switched. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml new file mode 100644 index 00000000000..3632730c5c6 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml @@ -0,0 +1,154 @@ + + + ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT + &manvol; + + + + VIDIOC_G_AUDOUT + VIDIOC_S_AUDOUT + Query or select the current audio output + + + + + + int ioctl + int fd + int request + struct v4l2_audioout *argp + + + + + int ioctl + int fd + int request + const struct v4l2_audioout *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT + + + + argp + + + + + + + + + Description + + To query the current audio output applications zero out the +reserved array of a &v4l2-audioout; and +call the VIDIOC_G_AUDOUT ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video output. + + Audio outputs have no writable properties. Nevertheless, to +select the current audio output applications can initialize the +index field and +reserved array (which in the future may +contain writable properties) of a +v4l2_audioout structure and call the +VIDIOC_S_AUDOUT ioctl. Drivers switch to the +requested output or return the &EINVAL; when the index is out of +bounds. This is a write-only ioctl, it does not return the current +audio output attributes as VIDIOC_G_AUDOUT +does. + + Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense. + + + struct <structname>v4l2_audioout</structname> + + &cs-str; + + + __u32 + index + Identifies the audio output, set by the +driver or application. + + + __u8 + name[32] + Name of the audio output, a NUL-terminated ASCII +string, for example: "Line Out". This information is intended for the +user, preferably the connector label on the device itself. + + + __u32 + capability + Audio capability flags, none defined yet. Drivers +must set this field to zero. + + + __u32 + mode + Audio mode, none defined yet. Drivers and +applications (on VIDIOC_S_AUDOUT) must set this +field to zero. + + + __u32 + reserved[2] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + No audio outputs combine with the current video +output, or the number of the selected audio output is out of bounds or +it does not combine, or there are no audio outputs at all and the +ioctl is not supported. + + + + EBUSY + + I/O is in progress, the output cannot be +switched. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml new file mode 100644 index 00000000000..d235b1dedbe --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml @@ -0,0 +1,143 @@ + + + ioctl VIDIOC_G_CROP, VIDIOC_S_CROP + &manvol; + + + + VIDIOC_G_CROP + VIDIOC_S_CROP + Get or set the current cropping rectangle + + + + + + int ioctl + int fd + int request + struct v4l2_crop *argp + + + + + int ioctl + int fd + int request + const struct v4l2_crop *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_CROP, VIDIOC_S_CROP + + + + argp + + + + + + + + + Description + + To query the cropping rectangle size and position +applications set the type field of a +v4l2_crop structure to the respective buffer +(stream) type and call the VIDIOC_G_CROP ioctl +with a pointer to this structure. The driver fills the rest of the +structure or returns the &EINVAL; if cropping is not supported. + + To change the cropping rectangle applications initialize the +type and &v4l2-rect; substructure named +c of a v4l2_crop structure and call the +VIDIOC_S_CROP ioctl with a pointer to this +structure. + + The driver first adjusts the requested dimensions against +hardware limits, &ie; the bounds given by the capture/output window, +and it rounds to the closest possible values of horizontal and +vertical offset, width and height. In particular the driver must round +the vertical offset of the cropping rectangle to frame lines modulo +two, such that the field order cannot be confused. + + Second the driver adjusts the image size (the opposite +rectangle of the scaling process, source or target depending on the +data direction) to the closest size possible while maintaining the +current horizontal and vertical scaling factor. + + Finally the driver programs the hardware with the actual +cropping and image parameters. VIDIOC_S_CROP is a +write-only ioctl, it does not return the actual parameters. To query +them applications must call VIDIOC_G_CROP and +&VIDIOC-G-FMT;. When the parameters are unsuitable the application may +modify the cropping or image parameters and repeat the cycle until +satisfactory parameters have been negotiated. + + When cropping is not supported then no parameters are +changed and VIDIOC_S_CROP returns the +&EINVAL;. + + + struct <structname>v4l2_crop</structname> + + &cs-str; + + + &v4l2-buf-type; + type + Type of the data stream, set by the application. +Only these types are valid here: V4L2_BUF_TYPE_VIDEO_CAPTURE, +V4L2_BUF_TYPE_VIDEO_OUTPUT, +V4L2_BUF_TYPE_VIDEO_OVERLAY, and custom (driver +defined) types with code V4L2_BUF_TYPE_PRIVATE +and higher. + + + &v4l2-rect; + c + Cropping rectangle. The same co-ordinate system as +for &v4l2-cropcap; bounds is used. + + + +
+ + + + &return-value; + + + + EINVAL + + Cropping is not supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml new file mode 100644 index 00000000000..8b5e6ff7f3d --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml @@ -0,0 +1,130 @@ + + + ioctl VIDIOC_G_CTRL, VIDIOC_S_CTRL + &manvol; + + + + VIDIOC_G_CTRL + VIDIOC_S_CTRL + Get or set the value of a control + + + + + + int ioctl + int fd + int request + struct v4l2_control +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_CTRL, VIDIOC_S_CTRL + + + + argp + + + + + + + + + Description + + To get the current value of a control applications +initialize the id field of a struct +v4l2_control and call the +VIDIOC_G_CTRL ioctl with a pointer to this +structure. To change the value of a control applications initialize +the id and value +fields of a struct v4l2_control and call the +VIDIOC_S_CTRL ioctl. + + When the id is invalid drivers +return an &EINVAL;. When the value is out +of bounds drivers can choose to take the closest valid value or return +an &ERANGE;, whatever seems more appropriate. However, +VIDIOC_S_CTRL is a write-only ioctl, it does not +return the actual new value. + + These ioctls work only with user controls. For other +control classes the &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; or +&VIDIOC-TRY-EXT-CTRLS; must be used. + + + struct <structname>v4l2_control</structname> + + &cs-str; + + + __u32 + id + Identifies the control, set by the +application. + + + __s32 + value + New value or current value. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-control; id is +invalid. + + + + ERANGE + + The &v4l2-control; value +is out of bounds. + + + + EBUSY + + The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml new file mode 100644 index 00000000000..d733721a751 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml @@ -0,0 +1,110 @@ + + + ioctl VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET + &manvol; + + + + VIDIOC_G_DV_PRESET + VIDIOC_S_DV_PRESET + Query or select the DV preset of the current input or output + + + + + + int ioctl + int fd + int request + struct v4l2_dv_preset *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET + + + + argp + + + + + + + + + Description + To query and select the current DV preset, applications +use the VIDIOC_G_DV_PRESET and VIDIOC_S_DV_PRESET +ioctls which take a pointer to a &v4l2-dv-preset; type as argument. +Applications must zero the reserved array in &v4l2-dv-preset;. +VIDIOC_G_DV_PRESET returns a dv preset in the field +preset of &v4l2-dv-preset;. + + VIDIOC_S_DV_PRESET accepts a pointer to a &v4l2-dv-preset; +that has the preset value to be set. Applications must zero the reserved array in &v4l2-dv-preset;. +If the preset is not supported, it returns an &EINVAL; + + + + &return-value; + + + + EINVAL + + This ioctl is not supported, or the +VIDIOC_S_DV_PRESET,VIDIOC_S_DV_PRESET parameter was unsuitable. + + + + EBUSY + + The device is busy and therefore can not change the preset. + + + + + + struct <structname>v4l2_dv_preset</structname> + + &cs-str; + + + __u32 + preset + Preset value to represent the digital video timings + + + __u32 + reserved[4] + Reserved fields for future use + + + +
+ + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml new file mode 100644 index 00000000000..d5ec6abf0ce --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml @@ -0,0 +1,223 @@ + + + ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS + &manvol; + + + + VIDIOC_G_DV_TIMINGS + VIDIOC_S_DV_TIMINGS + Get or set custom DV timings for input or output + + + + + + int ioctl + int fd + int request + struct v4l2_dv_timings *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS + + + + argp + + + + + + + + + Description + To set custom DV timings for the input or output, applications use the +VIDIOC_S_DV_TIMINGS ioctl and to get the current custom timings, +applications use the VIDIOC_G_DV_TIMINGS ioctl. The detailed timing +information is filled in using the structure &v4l2-dv-timings;. These ioctls take +a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported +or the timing values are not correct, the driver returns &EINVAL;. + + + + &return-value; + + + + EINVAL + + This ioctl is not supported, or the +VIDIOC_S_DV_TIMINGS parameter was unsuitable. + + + + EBUSY + + The device is busy and therefore can not change the timings. + + + + + + struct <structname>v4l2_bt_timings</structname> + + &cs-str; + + + __u32 + width + Width of the active video in pixels + + + __u32 + height + Height of the active video in lines + + + __u32 + interlaced + Progressive (0) or interlaced (1) + + + __u32 + polarities + This is a bit mask that defines polarities of sync signals. +bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set +(1) it is positive polarity and if is cleared (0), it is negative polarity. + + + __u64 + pixelclock + Pixel clock in Hz. Ex. 74.25MHz->74250000 + + + __u32 + hfrontporch + Horizontal front porch in pixels + + + __u32 + hsync + Horizontal sync length in pixels + + + __u32 + hbackporch + Horizontal back porch in pixels + + + __u32 + vfrontporch + Vertical front porch in lines + + + __u32 + vsync + Vertical sync length in lines + + + __u32 + vbackporch + Vertical back porch in lines + + + __u32 + il_vfrontporch + Vertical front porch in lines for bottom field of interlaced field formats + + + __u32 + il_vsync + Vertical sync length in lines for bottom field of interlaced field formats + + + __u32 + il_vbackporch + Vertical back porch in lines for bottom field of interlaced field formats + + + +
+ + + struct <structname>v4l2_dv_timings</structname> + + &cs-str; + + + __u32 + type + + Type of DV timings as listed in . + + + union + + + + + + &v4l2-bt-timings; + bt + Timings defined by BT.656/1120 specifications + + + + __u32 + reserved[32] + + + + +
+ + + DV Timing types + + &cs-str; + + + Timing type + value + Description + + + + + + + + V4L2_DV_BT_656_1120 + 0 + BT.656/1120 timings + + + +
+ + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml new file mode 100644 index 00000000000..9f242e4b294 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml @@ -0,0 +1,213 @@ + + + ioctl VIDIOC_G_ENC_INDEX + &manvol; + + + + VIDIOC_G_ENC_INDEX + Get meta data about a compressed video stream + + + + + + int ioctl + int fd + int request + struct v4l2_enc_idx *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_ENC_INDEX + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + The VIDIOC_G_ENC_INDEX ioctl provides +meta data about a compressed video stream the same or another +application currently reads from the driver, which is useful for +random access into the stream without decoding it. + + To read the data applications must call +VIDIOC_G_ENC_INDEX with a pointer to a +&v4l2-enc-idx;. On success the driver fills the +entry array, stores the number of elements +written in the entries field, and +initializes the entries_cap field. + + Each element of the entry array +contains meta data about one picture. A +VIDIOC_G_ENC_INDEX call reads up to +V4L2_ENC_IDX_ENTRIES entries from a driver +buffer, which can hold up to entries_cap +entries. This number can be lower or higher than +V4L2_ENC_IDX_ENTRIES, but not zero. When the +application fails to read the meta data in time the oldest entries +will be lost. When the buffer is empty or no capturing/encoding is in +progress, entries will be zero. + + Currently this ioctl is only defined for MPEG-2 program +streams and video elementary streams. + + + struct <structname>v4l2_enc_idx</structname> + + &cs-str; + + + __u32 + entries + The number of entries the driver stored in the +entry array. + + + __u32 + entries_cap + The number of entries the driver can +buffer. Must be greater than zero. + + + __u32 + reserved[4] + Reserved for future extensions. +Drivers must set the array to zero. + + + &v4l2-enc-idx-entry; + entry[V4L2_ENC_IDX_ENTRIES] + Meta data about a compressed video stream. Each +element of the array corresponds to one picture, sorted in ascending +order by their offset. + + + +
+ + + struct <structname>v4l2_enc_idx_entry</structname> + + &cs-str; + + + __u64 + offset + The offset in bytes from the beginning of the +compressed video stream to the beginning of this picture, that is a +PES packet header as defined in or a picture +header as defined in . When +the encoder is stopped, the driver resets the offset to zero. + + + __u64 + pts + The 33 bit Presentation Time +Stamp of this picture as defined in . + + + __u32 + length + The length of this picture in bytes. + + + __u32 + flags + Flags containing the coding type of this picture, see . + + + __u32 + reserved[2] + Reserved for future extensions. +Drivers must set the array to zero. + + + +
+ + + Index Entry Flags + + &cs-def; + + + V4L2_ENC_IDX_FRAME_I + 0x00 + This is an Intra-coded picture. + + + V4L2_ENC_IDX_FRAME_P + 0x01 + This is a Predictive-coded picture. + + + V4L2_ENC_IDX_FRAME_B + 0x02 + This is a Bidirectionally predictive-coded +picture. + + + V4L2_ENC_IDX_FRAME_MASK + 0x0F + AND the flags field with +this mask to obtain the picture coding type. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml new file mode 100644 index 00000000000..3aa7f8f9ff0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -0,0 +1,307 @@ + + + ioctl VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS + &manvol; + + + + VIDIOC_G_EXT_CTRLS + VIDIOC_S_EXT_CTRLS + VIDIOC_TRY_EXT_CTRLS + Get or set the value of several controls, try control +values + + + + + + int ioctl + int fd + int request + struct v4l2_ext_controls +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS + + + + argp + + + + + + + + + Description + + These ioctls allow the caller to get or set multiple +controls atomically. Control IDs are grouped into control classes (see +) and all controls in the control array +must belong to the same control class. + + Applications must always fill in the +count, +ctrl_class, +controls and +reserved fields of &v4l2-ext-controls;, and +initialize the &v4l2-ext-control; array pointed to by the +controls fields. + + To get the current value of a set of controls applications +initialize the id, +size and reserved2 fields +of each &v4l2-ext-control; and call the +VIDIOC_G_EXT_CTRLS ioctl. String controls controls +must also set the string field. + + If the size is too small to +receive the control result (only relevant for pointer-type controls +like strings), then the driver will set size +to a valid value and return an &ENOSPC;. You should re-allocate the +string memory to this new size and try again. It is possible that the +same issue occurs again if the string has grown in the meantime. It is +recommended to call &VIDIOC-QUERYCTRL; first and use +maximum+1 as the new size +value. It is guaranteed that that is sufficient memory. + + + To change the value of a set of controls applications +initialize the id, size, +reserved2 and +value/string fields of each &v4l2-ext-control; and +call the VIDIOC_S_EXT_CTRLS ioctl. The controls +will only be set if all control values are +valid. + + To check if a set of controls have correct values applications +initialize the id, size, +reserved2 and +value/string fields of each &v4l2-ext-control; and +call the VIDIOC_TRY_EXT_CTRLS ioctl. It is up to +the driver whether wrong values are automatically adjusted to a valid +value or if an error is returned. + + When the id or +ctrl_class is invalid drivers return an +&EINVAL;. When the value is out of bounds drivers can choose to take +the closest valid value or return an &ERANGE;, whatever seems more +appropriate. In the first case the new value is set in +&v4l2-ext-control;. + + The driver will only set/get these controls if all control +values are correct. This prevents the situation where only some of the +controls were set/get. Only low-level errors (⪚ a failed i2c +command) can still cause this situation. + + + struct <structname>v4l2_ext_control</structname> + + &cs-ustr; + + + __u32 + id + + Identifies the control, set by the +application. + + + __u32 + size + + The total size in bytes of the payload of this +control. This is normally 0, but for pointer controls this should be +set to the size of the memory containing the payload, or that will +receive the payload. If VIDIOC_G_EXT_CTRLS finds +that this value is less than is required to store +the payload result, then it is set to a value large enough to store the +payload result and ENOSPC is returned. Note that for string controls +this size field should not be confused with the length of the string. +This field refers to the size of the memory that contains the string. +The actual length of the string may well be much smaller. + + + + __u32 + reserved2[1] + + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + union + (anonymous) + + + + __s32 + value + New value or current value. + + + + __s64 + value64 + New value or current value. + + + + char * + string + A pointer to a string. + + + +
+ + + struct <structname>v4l2_ext_controls</structname> + + &cs-str; + + + __u32 + ctrl_class + The control class to which all controls belong, see +. + + + __u32 + count + The number of controls in the controls array. May +also be zero. + + + __u32 + error_idx + Set by the driver in case of an error. It is the +index of the control causing the error or equal to 'count' when the +error is not associated with a particular control. Undefined when the +ioctl returns 0 (success). + + + __u32 + reserved[2] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + &v4l2-ext-control; * + controls + Pointer to an array of +count v4l2_ext_control structures. Ignored +if count equals zero. + + + +
+ + + Control classes + + &cs-def; + + + V4L2_CTRL_CLASS_USER + 0x980000 + The class containing user controls. These controls +are described in . All controls that can be set +using the &VIDIOC-S-CTRL; and &VIDIOC-G-CTRL; ioctl belong to this +class. + + + V4L2_CTRL_CLASS_MPEG + 0x990000 + The class containing MPEG compression controls. +These controls are described in . + + + V4L2_CTRL_CLASS_CAMERA + 0x9a0000 + The class containing camera controls. +These controls are described in . + + + V4L2_CTRL_CLASS_FM_TX + 0x9b0000 + The class containing FM Transmitter (FM TX) controls. +These controls are described in . + + + +
+ + + + + &return-value; + + + + EINVAL + + The &v4l2-ext-control; id +is invalid or the &v4l2-ext-controls; +ctrl_class is invalid. This error code is +also returned by the VIDIOC_S_EXT_CTRLS and +VIDIOC_TRY_EXT_CTRLS ioctls if two or more +control values are in conflict. + + + + ERANGE + + The &v4l2-ext-control; value +is out of bounds. + + + + EBUSY + + The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to. + + + + ENOSPC + + The space reserved for the control's payload is insufficient. +The field size is set to a value that is enough +to store the payload and this error code is returned. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml new file mode 100644 index 00000000000..e7dda4822f0 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml @@ -0,0 +1,473 @@ + + + ioctl VIDIOC_G_FBUF, VIDIOC_S_FBUF + &manvol; + + + + VIDIOC_G_FBUF + VIDIOC_S_FBUF + Get or set frame buffer overlay parameters + + + + + + int ioctl + int fd + int request + struct v4l2_framebuffer *argp + + + + + int ioctl + int fd + int request + const struct v4l2_framebuffer *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_FBUF, VIDIOC_S_FBUF + + + + argp + + + + + + + + + Description + + Applications can use the VIDIOC_G_FBUF and +VIDIOC_S_FBUF ioctl to get and set the +framebuffer parameters for a Video +Overlay or Video Output Overlay +(OSD). The type of overlay is implied by the device type (capture or +output device) and can be determined with the &VIDIOC-QUERYCAP; ioctl. +One /dev/videoN device must not support both +kinds of overlay. + + The V4L2 API distinguishes destructive and non-destructive +overlays. A destructive overlay copies captured video images into the +video memory of a graphics card. A non-destructive overlay blends +video images into a VGA signal or graphics into a video signal. +Video Output Overlays are always +non-destructive. + + To get the current parameters applications call the +VIDIOC_G_FBUF ioctl with a pointer to a +v4l2_framebuffer structure. The driver fills +all fields of the structure or returns an &EINVAL; when overlays are +not supported. + + To set the parameters for a Video Output +Overlay, applications must initialize the +flags field of a struct +v4l2_framebuffer. Since the framebuffer is +implemented on the TV card all other parameters are determined by the +driver. When an application calls VIDIOC_S_FBUF +with a pointer to this structure, the driver prepares for the overlay +and returns the framebuffer parameters as +VIDIOC_G_FBUF does, or it returns an error +code. + + To set the parameters for a non-destructive +Video Overlay, applications must initialize the +flags field, the +fmt substructure, and call +VIDIOC_S_FBUF. Again the driver prepares for the +overlay and returns the framebuffer parameters as +VIDIOC_G_FBUF does, or it returns an error +code. + + For a destructive Video Overlay +applications must additionally provide a +base address. Setting up a DMA to a +random memory location can jeopardize the system security, its +stability or even damage the hardware, therefore only the superuser +can set the parameters for a destructive video overlay. + + + + + struct <structname>v4l2_framebuffer</structname> + + &cs-ustr; + + + __u32 + capability + + Overlay capability flags set by the driver, see +. + + + __u32 + flags + + Overlay control flags set by application and +driver, see + + + void * + base + + Physical base address of the framebuffer, +that is the address of the pixel in the top left corner of the +framebuffer.A physical base address may not suit all +platforms. GK notes in theory we should pass something like PCI device ++ memory region + offset instead. If you encounter problems please +discuss on the linux-media mailing list: &v4l-ml;. + + + + + + This field is irrelevant to +non-destructive Video Overlays. For +destructive Video Overlays applications must +provide a base address. The driver may accept only base addresses +which are a multiple of two, four or eight bytes. For +Video Output Overlays the driver must return +a valid base address, so applications can find the corresponding Linux +framebuffer device (see ). + + + &v4l2-pix-format; + fmt + + Layout of the frame buffer. The +v4l2_pix_format structure is defined in , for clarification the fields and acceptable values + are listed below: + + + + __u32 + width + Width of the frame buffer in pixels. + + + + __u32 + height + Height of the frame buffer in pixels. + + + + __u32 + pixelformat + The pixel format of the +framebuffer. + + + + + + For non-destructive Video +Overlays this field only defines a format for the +&v4l2-window; chromakey field. + + + + + + For destructive Video +Overlays applications must initialize this field. For +Video Output Overlays the driver must return +a valid format. + + + + + + Usually this is an RGB format (for example +V4L2_PIX_FMT_RGB565) +but YUV formats (only packed YUV formats when chroma keying is used, +not including V4L2_PIX_FMT_YUYV and +V4L2_PIX_FMT_UYVY) and the +V4L2_PIX_FMT_PAL8 format are also permitted. The +behavior of the driver when an application requests a compressed +format is undefined. See for information on +pixel formats. + + + + &v4l2-field; + field + Drivers and applications shall ignore this field. +If applicable, the field order is selected with the &VIDIOC-S-FMT; +ioctl, using the field field of +&v4l2-window;. + + + + __u32 + bytesperline + Distance in bytes between the leftmost pixels in +two adjacent lines. + + + This field is irrelevant to +non-destructive Video +Overlays.For destructive Video +Overlays both applications and drivers can set this field +to request padding bytes at the end of each line. Drivers however may +ignore the requested value, returning width +times bytes-per-pixel or a larger value required by the hardware. That +implies applications can just set this field to zero to get a +reasonable default.For Video Output +Overlays the driver must return a valid +value.Video hardware may access padding bytes, therefore +they must reside in accessible memory. Consider for example the case +where padding bytes after the last line of an image cross a system +page boundary. Capture devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.When the image format is planar the +bytesperline value applies to the largest +plane and is divided by the same factor as the +width field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a bytesperline value +rounded up to a multiple of the scale factor. + + + + __u32 + sizeimage + This field is irrelevant to +non-destructive Video Overlays. For +destructive Video Overlays applications must +initialize this field. For Video Output +Overlays the driver must return a valid +format.Together with base it +defines the framebuffer memory accessible by the +driver. + + + + &v4l2-colorspace; + colorspace + This information supplements the +pixelformat and must be set by the driver, +see . + + + + __u32 + priv + Reserved for additional information about custom +(driver defined) formats. When not used drivers and applications must +set this field to zero. + + + +
+ + + Frame Buffer Capability Flags + + &cs-def; + + + V4L2_FBUF_CAP_EXTERNOVERLAY + 0x0001 + The device is capable of non-destructive overlays. +When the driver clears this flag, only destructive overlays are +supported. There are no drivers yet which support both destructive and +non-destructive overlays. + + + V4L2_FBUF_CAP_CHROMAKEY + 0x0002 + The device supports clipping by chroma-keying the +images. That is, image pixels replace pixels in the VGA or video +signal only where the latter assume a certain color. Chroma-keying +makes no sense for destructive overlays. + + + V4L2_FBUF_CAP_LIST_CLIPPING + 0x0004 + The device supports clipping using a list of clip +rectangles. + + + V4L2_FBUF_CAP_BITMAP_CLIPPING + 0x0008 + The device supports clipping using a bit mask. + + + V4L2_FBUF_CAP_LOCAL_ALPHA + 0x0010 + The device supports clipping/blending using the +alpha channel of the framebuffer or VGA signal. Alpha blending makes +no sense for destructive overlays. + + + V4L2_FBUF_CAP_GLOBAL_ALPHA + 0x0020 + The device supports alpha blending using a global +alpha value. Alpha blending makes no sense for destructive overlays. + + + V4L2_FBUF_CAP_LOCAL_INV_ALPHA + 0x0040 + The device supports clipping/blending using the +inverted alpha channel of the framebuffer or VGA signal. Alpha +blending makes no sense for destructive overlays. + + + V4L2_FBUF_CAP_SRC_CHROMAKEY + 0x0080 + The device supports Source Chroma-keying. Framebuffer pixels +with the chroma-key colors are replaced by video pixels, which is exactly opposite of +V4L2_FBUF_CAP_CHROMAKEY + + + +
+ + + Frame Buffer Flags + + &cs-def; + + + V4L2_FBUF_FLAG_PRIMARY + 0x0001 + The framebuffer is the primary graphics surface. +In other words, the overlay is destructive. [?] + + + V4L2_FBUF_FLAG_OVERLAY + 0x0002 + The frame buffer is an overlay surface the same +size as the capture. [?] + + + The purpose of +V4L2_FBUF_FLAG_PRIMARY and +V4L2_FBUF_FLAG_OVERLAY was never quite clear. +Most drivers seem to ignore these flags. For compatibility with the +bttv driver applications should set the +V4L2_FBUF_FLAG_OVERLAY flag. + + + V4L2_FBUF_FLAG_CHROMAKEY + 0x0004 + Use chroma-keying. The chroma-key color is +determined by the chromakey field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see +and + . + + + There are no flags to enable +clipping using a list of clip rectangles or a bitmap. These methods +are negotiated with the &VIDIOC-S-FMT; ioctl, see and . + + + V4L2_FBUF_FLAG_LOCAL_ALPHA + 0x0008 + Use the alpha channel of the framebuffer to clip or +blend framebuffer pixels with video images. The blend +function is: output = framebuffer pixel * alpha + video pixel * (1 - +alpha). The actual alpha depth depends on the framebuffer pixel +format. + + + V4L2_FBUF_FLAG_GLOBAL_ALPHA + 0x0010 + Use a global alpha value to blend the framebuffer +with video images. The blend function is: output = (framebuffer pixel +* alpha + video pixel * (255 - alpha)) / 255. The alpha value is +determined by the global_alpha field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see +and . + + + V4L2_FBUF_FLAG_LOCAL_INV_ALPHA + 0x0020 + Like +V4L2_FBUF_FLAG_LOCAL_ALPHA, use the alpha channel +of the framebuffer to clip or blend framebuffer pixels with video +images, but with an inverted alpha value. The blend function is: +output = framebuffer pixel * (1 - alpha) + video pixel * alpha. The +actual alpha depth depends on the framebuffer pixel format. + + + V4L2_FBUF_FLAG_SRC_CHROMAKEY + 0x0040 + Use source chroma-keying. The source chroma-key color is +determined by the chromakey field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see and . +Both chroma-keying are mutual exclusive to each other, so same +chromakey field of &v4l2-window; is being used. + + + +
+ + + + &return-value; + + + + EPERM + + VIDIOC_S_FBUF can only be called +by a privileged user to negotiate the parameters for a destructive +overlay. + + + + EBUSY + + The framebuffer parameters cannot be changed at this +time because overlay is already enabled, or capturing is enabled +and the hardware cannot capture and overlay simultaneously. + + + + EINVAL + + The ioctl is not supported or the +VIDIOC_S_FBUF parameters are unsuitable. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml new file mode 100644 index 00000000000..a4ae59b664e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml @@ -0,0 +1,212 @@ + + + ioctl VIDIOC_G_FMT, VIDIOC_S_FMT, +VIDIOC_TRY_FMT + &manvol; + + + + VIDIOC_G_FMT + VIDIOC_S_FMT + VIDIOC_TRY_FMT + Get or set the data format, try a format + + + + + + int ioctl + int fd + int request + struct v4l2_format +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_FMT, VIDIOC_S_FMT, VIDIOC_TRY_FMT + + + + argp + + + + + + + + + Description + + These ioctls are used to negotiate the format of data +(typically image format) exchanged between driver and +application. + + To query the current parameters applications set the +type field of a struct +v4l2_format to the respective buffer (stream) +type. For example video capture devices use +V4L2_BUF_TYPE_VIDEO_CAPTURE or +V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE. When the application +calls the VIDIOC_G_FMT ioctl with a pointer to +this structure the driver fills the respective member of the +fmt union. In case of video capture devices +that is either the &v4l2-pix-format; pix or +the &v4l2-pix-format-mplane; pix_mp member. +When the requested buffer type is not supported drivers return an +&EINVAL;. + + To change the current format parameters applications +initialize the type field and all +fields of the respective fmt +union member. For details see the documentation of the various devices +types in . Good practice is to query the +current parameters first, and to +modify only those parameters not suitable for the application. When +the application calls the VIDIOC_S_FMT ioctl +with a pointer to a v4l2_format structure +the driver checks +and adjusts the parameters against hardware abilities. Drivers +should not return an error code unless the input is ambiguous, this is +a mechanism to fathom device capabilities and to approach parameters +acceptable for both the application and driver. On success the driver +may program the hardware, allocate resources and generally prepare for +data exchange. +Finally the VIDIOC_S_FMT ioctl returns the +current format parameters as VIDIOC_G_FMT does. +Very simple, inflexible devices may even ignore all input and always +return the default parameters. However all V4L2 devices exchanging +data with the application must implement the +VIDIOC_G_FMT and +VIDIOC_S_FMT ioctl. When the requested buffer +type is not supported drivers return an &EINVAL; on a +VIDIOC_S_FMT attempt. When I/O is already in +progress or the resource is not available for other reasons drivers +return the &EBUSY;. + + The VIDIOC_TRY_FMT ioctl is equivalent +to VIDIOC_S_FMT with one exception: it does not +change driver state. It can also be called at any time, never +returning EBUSY. This function is provided to +negotiate parameters, to learn about hardware limitations, without +disabling I/O or possibly time consuming hardware preparations. +Although strongly recommended drivers are not required to implement +this ioctl. + + + struct <structname>v4l2_format</structname> + + + + + + + + &v4l2-buf-type; + type + + Type of the data stream, see . + + + union + fmt + + + + &v4l2-pix-format; + pix + Definition of an image format, see , used by video capture and output +devices. + + + + &v4l2-pix-format-mplane; + pix_mp + Definition of an image format, see , used by video capture and output +devices that support the multi-planar +version of the API. + + + + &v4l2-window; + win + Definition of an overlaid image, see , used by video overlay devices. + + + + &v4l2-vbi-format; + vbi + Raw VBI capture or output parameters. This is +discussed in more detail in . Used by raw VBI +capture and output devices. + + + + &v4l2-sliced-vbi-format; + sliced + Sliced VBI capture or output parameters. See + for details. Used by sliced VBI +capture and output devices. + + + + __u8 + raw_data[200] + Place holder for future extensions and custom +(driver defined) formats with type +V4L2_BUF_TYPE_PRIVATE and higher. + + + +
+ + + + &return-value; + + + + EBUSY + + The data format cannot be changed at this +time, for example because I/O is already in progress. + + + + EINVAL + + The &v4l2-format; type +field is invalid, the requested buffer type not supported, or +VIDIOC_TRY_FMT was called and is not +supported with this buffer type. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml b/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml new file mode 100644 index 00000000000..062d7206909 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml @@ -0,0 +1,145 @@ + + + ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY + &manvol; + + + + VIDIOC_G_FREQUENCY + VIDIOC_S_FREQUENCY + Get or set tuner or modulator radio +frequency + + + + + + int ioctl + int fd + int request + struct v4l2_frequency +*argp + + + + + int ioctl + int fd + int request + const struct v4l2_frequency +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY + + + + argp + + + + + + + + + Description + + To get the current tuner or modulator radio frequency +applications set the tuner field of a +&v4l2-frequency; to the respective tuner or modulator number (only +input devices have tuners, only output devices have modulators), zero +out the reserved array and +call the VIDIOC_G_FREQUENCY ioctl with a pointer +to this structure. The driver stores the current frequency in the +frequency field. + + To change the current tuner or modulator radio frequency +applications initialize the tuner, +type and +frequency fields, and the +reserved array of a &v4l2-frequency; and +call the VIDIOC_S_FREQUENCY ioctl with a pointer +to this structure. When the requested frequency is not possible the +driver assumes the closest possible value. However +VIDIOC_S_FREQUENCY is a write-only ioctl, it does +not return the actual new frequency. + + + struct <structname>v4l2_frequency</structname> + + &cs-str; + + + __u32 + tuner + The tuner or modulator index number. This is the +same value as in the &v4l2-input; tuner +field and the &v4l2-tuner; index field, or +the &v4l2-output; modulator field and the +&v4l2-modulator; index field. + + + &v4l2-tuner-type; + type + The tuner type. This is the same value as in the +&v4l2-tuner; type field. The field is not +applicable to modulators, &ie; ignored by drivers. + + + __u32 + frequency + Tuning frequency in units of 62.5 kHz, or if the +&v4l2-tuner; or &v4l2-modulator; capabilities flag +V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + reserved[8] + Reserved for future extensions. Drivers and + applications must set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + The tuner index is out of +bounds or the value in the type field is +wrong. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-input.xml b/Documentation/DocBook/media/v4l/vidioc-g-input.xml new file mode 100644 index 00000000000..ed076e92760 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-input.xml @@ -0,0 +1,100 @@ + + + ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT + &manvol; + + + + VIDIOC_G_INPUT + VIDIOC_S_INPUT + Query or select the current video input + + + + + + int ioctl + int fd + int request + int *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_INPUT, VIDIOC_S_INPUT + + + + argp + + + + + + + + + Description + + To query the current video input applications call the +VIDIOC_G_INPUT ioctl with a pointer to an integer +where the driver stores the number of the input, as in the +&v4l2-input; index field. This ioctl will +fail only when there are no video inputs, returning +EINVAL. + + To select a video input applications store the number of the +desired input in an integer and call the +VIDIOC_S_INPUT ioctl with a pointer to this +integer. Side effects are possible. For example inputs may support +different video standards, so the driver may implicitly switch the +current standard. It is good practice to select an input before +querying or negotiating any other parameters. + + Information about video inputs is available using the +&VIDIOC-ENUMINPUT; ioctl. + + + + &return-value; + + + + EINVAL + + The number of the video input is out of bounds, or +there are no video inputs at all and this ioctl is not +supported. + + + + EBUSY + + I/O is in progress, the input cannot be +switched. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml new file mode 100644 index 00000000000..77394b28741 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml @@ -0,0 +1,180 @@ + + + ioctl VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP + &manvol; + + + + VIDIOC_G_JPEGCOMP + VIDIOC_S_JPEGCOMP + + + + + + + int ioctl + int fd + int request + v4l2_jpegcompression *argp + + + + + int ioctl + int fd + int request + const v4l2_jpegcompression *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP + + + + argp + + + + + + + + + Description + + [to do] + + Ronald Bultje elaborates: + + + + APP is some application-specific information. The +application can set it itself, and it'll be stored in the JPEG-encoded +fields (eg; interlacing information for in an AVI or so). COM is the +same, but it's comments, like 'encoded by me' or so. + + jpeg_markers describes whether the huffman tables, +quantization tables and the restart interval information (all +JPEG-specific stuff) should be stored in the JPEG-encoded fields. +These define how the JPEG field is encoded. If you omit them, +applications assume you've used standard encoding. You usually do want +to add them. + + + + + struct <structname>v4l2_jpegcompression</structname> + + &cs-str; + + + int + quality + + + + int + APPn + + + + int + APP_len + + + + char + APP_data[60] + + + + int + COM_len + + + + char + COM_data[60] + + + + __u32 + jpeg_markers + See . + + + +
+ + + JPEG Markers Flags + + &cs-def; + + + V4L2_JPEG_MARKER_DHT + (1<<3) + Define Huffman Tables + + + V4L2_JPEG_MARKER_DQT + (1<<4) + Define Quantization Tables + + + V4L2_JPEG_MARKER_DRI + (1<<5) + Define Restart Interval + + + V4L2_JPEG_MARKER_COM + (1<<6) + Comment segment + + + V4L2_JPEG_MARKER_APP + (1<<7) + App segment, driver will always use APP0 + + + +
+ + + + &return-value; + + + + EINVAL + + This ioctl is not supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml new file mode 100644 index 00000000000..15ce660f0f5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml @@ -0,0 +1,246 @@ + + + ioctl VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR + &manvol; + + + + VIDIOC_G_MODULATOR + VIDIOC_S_MODULATOR + Get or set modulator attributes + + + + + + int ioctl + int fd + int request + struct v4l2_modulator +*argp + + + + + int ioctl + int fd + int request + const struct v4l2_modulator +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR + + + + argp + + + + + + + + + Description + + To query the attributes of a modulator applications initialize +the index field and zero out the +reserved array of a &v4l2-modulator; and +call the VIDIOC_G_MODULATOR ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all modulators +applications shall begin at index zero, incrementing by one until the +driver returns EINVAL. + + Modulators have two writable properties, an audio +modulation set and the radio frequency. To change the modulated audio +subprograms, applications initialize the index + and txsubchans fields and the +reserved array and call the +VIDIOC_S_MODULATOR ioctl. Drivers may choose a +different audio modulation if the request cannot be satisfied. However +this is a write-only ioctl, it does not return the actual audio +modulation selected. + + To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available. + + + struct <structname>v4l2_modulator</structname> + + &cs-str; + + + __u32 + index + Identifies the modulator, set by the +application. + + + __u8 + name[32] + Name of the modulator, a NUL-terminated ASCII +string. This information is intended for the user. + + + __u32 + capability + Modulator capability flags. No flags are defined +for this field, the tuner flags in &v4l2-tuner; +are used accordingly. The audio flags indicate the ability +to encode audio subprograms. They will not +change for example with the current video standard. + + + __u32 + rangelow + The lowest tunable frequency in units of 62.5 +KHz, or if the capability flag +V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + rangehigh + The highest tunable frequency in units of 62.5 +KHz, or if the capability flag +V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + txsubchans + With this field applications can determine how +audio sub-carriers shall be modulated. It contains a set of flags as +defined in . Note the tuner +rxsubchans flags are reused, but the +semantics are different. Video output devices are assumed to have an +analog or PCM audio input with 1-3 channels. The +txsubchans flags select one or more +channels for modulation, together with some audio subprogram +indicator, for example a stereo pilot tone. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Modulator Audio Transmission Flags + + &cs-def; + + + V4L2_TUNER_SUB_MONO + 0x0001 + Modulate channel 1 as mono audio, when the input +has more channels, a down-mix of channel 1 and 2. This flag does not +combine with V4L2_TUNER_SUB_STEREO or +V4L2_TUNER_SUB_LANG1. + + + V4L2_TUNER_SUB_STEREO + 0x0002 + Modulate channel 1 and 2 as left and right +channel of a stereo audio signal. When the input has only one channel +or two channels and V4L2_TUNER_SUB_SAP is also +set, channel 1 is encoded as left and right channel. This flag does +not combine with V4L2_TUNER_SUB_MONO or +V4L2_TUNER_SUB_LANG1. When the driver does not +support stereo audio it shall fall back to mono. + + + V4L2_TUNER_SUB_LANG1 + 0x0008 + Modulate channel 1 and 2 as primary and secondary +language of a bilingual audio signal. When the input has only one +channel it is used for both languages. It is not possible to encode +the primary or secondary language only. This flag does not combine +with V4L2_TUNER_SUB_MONO, +V4L2_TUNER_SUB_STEREO or +V4L2_TUNER_SUB_SAP. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit bilingual audio the +VIDIOC_S_MODULATOR ioctl shall return an &EINVAL; +and the driver shall fall back to mono or stereo mode. + + + V4L2_TUNER_SUB_LANG2 + 0x0004 + Same effect as +V4L2_TUNER_SUB_SAP. + + + V4L2_TUNER_SUB_SAP + 0x0004 + When combined with V4L2_TUNER_SUB_MONO + the first channel is encoded as mono audio, the last +channel as Second Audio Program. When the input has only one channel +it is used for both audio tracks. When the input has three channels +the mono track is a down-mix of channel 1 and 2. When combined with +V4L2_TUNER_SUB_STEREO channel 1 and 2 are +encoded as left and right stereo audio, channel 3 as Second Audio +Program. When the input has only two channels, the first is encoded as +left and right channel and the second as SAP. When the input has only +one channel it is used for all audio tracks. It is not possible to +encode a Second Audio Program only. This flag must combine with +V4L2_TUNER_SUB_MONO or +V4L2_TUNER_SUB_STEREO. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit SAP the VIDIOC_S_MODULATOR ioctl +shall return an &EINVAL; and driver shall fall back to mono or stereo +mode. + + + V4L2_TUNER_SUB_RDS + 0x0010 + Enable the RDS encoder for a radio FM transmitter. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-modulator; +index is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-output.xml b/Documentation/DocBook/media/v4l/vidioc-g-output.xml new file mode 100644 index 00000000000..3ea8c0ed812 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-output.xml @@ -0,0 +1,100 @@ + + + ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT + &manvol; + + + + VIDIOC_G_OUTPUT + VIDIOC_S_OUTPUT + Query or select the current video output + + + + + + int ioctl + int fd + int request + int *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT + + + + argp + + + + + + + + + Description + + To query the current video output applications call the +VIDIOC_G_OUTPUT ioctl with a pointer to an integer +where the driver stores the number of the output, as in the +&v4l2-output; index field. This ioctl +will fail only when there are no video outputs, returning the +&EINVAL;. + + To select a video output applications store the number of the +desired output in an integer and call the +VIDIOC_S_OUTPUT ioctl with a pointer to this integer. +Side effects are possible. For example outputs may support different +video standards, so the driver may implicitly switch the current +standard. It is good practice to select an output before querying or +negotiating any other parameters. + + Information about video outputs is available using the +&VIDIOC-ENUMOUTPUT; ioctl. + + + + &return-value; + + + + EINVAL + + The number of the video output is out of bounds, or +there are no video outputs at all and this ioctl is not +supported. + + + + EBUSY + + I/O is in progress, the output cannot be +switched. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-parm.xml b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml new file mode 100644 index 00000000000..392aa9e5571 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml @@ -0,0 +1,332 @@ + + + ioctl VIDIOC_G_PARM, VIDIOC_S_PARM + &manvol; + + + + VIDIOC_G_PARM + VIDIOC_S_PARM + Get or set streaming parameters + + + + + + int ioctl + int fd + int request + v4l2_streamparm *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_PARM, VIDIOC_S_PARM + + + + argp + + + + + + + + + Description + + The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the read() or write(), which +are not augmented by timestamps or sequence counters, and to avoid +unnecessary data copying. + + Further these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function. + + To get and set the streaming parameters applications call +the VIDIOC_G_PARM and +VIDIOC_S_PARM ioctl, respectively. They take a +pointer to a struct v4l2_streamparm which +contains a union holding separate parameters for input and output +devices. + + + struct <structname>v4l2_streamparm</structname> + + &cs-ustr; + + + &v4l2-buf-type; + type + + The buffer (stream) type, same as &v4l2-format; +type, set by the application. + + + union + parm + + + + + + &v4l2-captureparm; + capture + Parameters for capture devices, used when +type is +V4L2_BUF_TYPE_VIDEO_CAPTURE. + + + + &v4l2-outputparm; + output + Parameters for output devices, used when +type is +V4L2_BUF_TYPE_VIDEO_OUTPUT. + + + + __u8 + raw_data[200] + A place holder for future extensions and custom +(driver defined) buffer types V4L2_BUF_TYPE_PRIVATE and +higher. + + + +
+ + + struct <structname>v4l2_captureparm</structname> + + &cs-str; + + + __u32 + capability + See . + + + __u32 + capturemode + Set by drivers and applications, see . + + + &v4l2-fract; + timeperframe + This is is the desired period between +successive frames captured by the driver, in seconds. The +field is intended to skip frames on the driver side, saving I/O +bandwidth.Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; frameperiod +field). Changing the video standard (also implicitly by switching the +video input) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.Drivers support this function only when they set the +V4L2_CAP_TIMEPERFRAME flag in the +capability field. + + + __u32 + extendedmode + Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see . + + + __u32 + readbuffers + Applications set this field to the desired number +of buffers used internally by the driver in &func-read; mode. Drivers +return the actual number of buffers. When an application requests zero +buffers, drivers should just return the current setting rather than +the minimum or an error code. For details see . + + + __u32 + reserved[4] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + struct <structname>v4l2_outputparm</structname> + + &cs-str; + + + __u32 + capability + See . + + + __u32 + outputmode + Set by drivers and applications, see . + + + &v4l2-fract; + timeperframe + This is is the desired period between +successive frames output by the driver, in seconds. + + + The field is intended to +repeat frames on the driver side in &func-write; mode (in streaming +mode timestamps can be used to throttle the output), saving I/O +bandwidth.Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; frameperiod +field). Changing the video standard (also implicitly by switching the +video output) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.Drivers support this function only when they set the +V4L2_CAP_TIMEPERFRAME flag in the +capability field. + + + __u32 + extendedmode + Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see . + + + __u32 + writebuffers + Applications set this field to the desired number +of buffers used internally by the driver in +write() mode. Drivers return the actual number of +buffers. When an application requests zero buffers, drivers should +just return the current setting rather than the minimum or an error +code. For details see . + + + __u32 + reserved[4] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Streaming Parameters Capabilites + + &cs-def; + + + V4L2_CAP_TIMEPERFRAME + 0x1000 + The frame skipping/repeating controlled by the +timeperframe field is supported. + + + +
+ + + Capture Parameters Flags + + &cs-def; + + + V4L2_MODE_HIGHQUALITY + 0x0001 + High quality imaging mode. High quality mode +is intended for still imaging applications. The idea is to get the +best possible image quality that the hardware can deliver. It is not +defined how the driver writer may achieve that; it will depend on the +hardware and the ingenuity of the driver writer. High quality mode is +a different mode from the the regular motion video capture modes. In +high quality mode: + + The driver may be able to capture higher +resolutions than for motion capture. + + + The driver may support fewer pixel formats +than motion capture (eg; true color). + + + The driver may capture and arithmetically +combine multiple successive fields or frames to remove color edge +artifacts and reduce the noise in the video data. + + + + The driver may capture images in slices like +a scanner in order to handle larger format images than would otherwise +be possible. + + + An image capture operation may be +significantly slower than motion capture. + + + Moving objects in the image might have +excessive motion blur. + + + Capture might only work through the +read() call. + + + + + +
+ + + + + &return-value; + + + + EINVAL + + This ioctl is not supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-priority.xml b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml new file mode 100644 index 00000000000..5fb00197864 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml @@ -0,0 +1,144 @@ + + + ioctl VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY + &manvol; + + + + VIDIOC_G_PRIORITY + VIDIOC_S_PRIORITY + Query or request the access priority associated with a +file descriptor + + + + + + int ioctl + int fd + int request + enum v4l2_priority *argp + + + + + int ioctl + int fd + int request + const enum v4l2_priority *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY + + + + argp + + Pointer to an enum v4l2_priority type. + + + + + + + Description + + To query the current access priority +applications call the VIDIOC_G_PRIORITY ioctl +with a pointer to an enum v4l2_priority variable where the driver stores +the current priority. + + To request an access priority applications store the +desired priority in an enum v4l2_priority variable and call +VIDIOC_S_PRIORITY ioctl with a pointer to this +variable. + + + enum v4l2_priority + + &cs-def; + + + V4L2_PRIORITY_UNSET + 0 + + + + V4L2_PRIORITY_BACKGROUND + 1 + Lowest priority, usually applications running in +background, for example monitoring VBI transmissions. A proxy +application running in user space will be necessary if multiple +applications want to read from a device at this priority. + + + V4L2_PRIORITY_INTERACTIVE + 2 + + + + V4L2_PRIORITY_DEFAULT + 2 + Medium priority, usually applications started and +interactively controlled by the user. For example TV viewers, Teletext +browsers, or just "panel" applications to change the channel or video +controls. This is the default priority unless an application requests +another. + + + V4L2_PRIORITY_RECORD + 3 + Highest priority. Only one file descriptor can have +this priority, it blocks any other fd from changing device properties. +Usually applications which must not be interrupted, like video +recording. + + + +
+ + + + &return-value; + + + + EINVAL + + The requested priority value is invalid, or the +driver does not support access priorities. + + + + EBUSY + + Another application already requested higher +priority. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml new file mode 100644 index 00000000000..10e721b1737 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml @@ -0,0 +1,264 @@ + + + ioctl VIDIOC_G_SLICED_VBI_CAP + &manvol; + + + + VIDIOC_G_SLICED_VBI_CAP + Query sliced VBI capabilities + + + + + + int ioctl + int fd + int request + struct v4l2_sliced_vbi_cap *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_SLICED_VBI_CAP + + + + argp + + + + + + + + + Description + + To find out which data services are supported by a sliced +VBI capture or output device, applications initialize the +type field of a &v4l2-sliced-vbi-cap;, +clear the reserved array and +call the VIDIOC_G_SLICED_VBI_CAP ioctl. The +driver fills in the remaining fields or returns an &EINVAL; if the +sliced VBI API is unsupported or type +is invalid. + + Note the type field was added, +and the ioctl changed from read-only to write-read, in Linux 2.6.19. + + + struct <structname>v4l2_sliced_vbi_cap</structname> + + + + + + + + + + __u16 + service_set + A set of all data services +supported by the driver. Equal to the union of all elements of the +service_lines array. + + + __u16 + service_lines[2][24] + Each element of this array +contains a set of data services the hardware can look for or insert +into a particular scan line. Data services are defined in . Array indices map to ITU-R +line numbers (see also and ) as follows: + + + + + Element + 525 line systems + 625 line systems + + + + + service_lines[0][1] + 1 + 1 + + + + + service_lines[0][23] + 23 + 23 + + + + + service_lines[1][1] + 264 + 314 + + + + + service_lines[1][23] + 286 + 336 + + + + + + + + The number of VBI lines the +hardware can capture or output per frame, or the number of services it +can identify on a given line may be limited. For example on PAL line +16 the hardware may be able to look for a VPS or Teletext signal, but +not both at the same time. Applications can learn about these limits +using the &VIDIOC-S-FMT; ioctl as described in . + + + + + + + + Drivers must set +service_lines[0][0] and +service_lines[1][0] to zero. + + + &v4l2-buf-type; + type + Type of the data stream, see . Should be +V4L2_BUF_TYPE_SLICED_VBI_CAPTURE or +V4L2_BUF_TYPE_SLICED_VBI_OUTPUT. + + + __u32 + reserved[3] + This array is reserved for future +extensions. Applications and drivers must set it to zero. + + + +
+ + + + Sliced VBI services + + + + + + + + + + Symbol + Value + Reference + Lines, usually + Payload + + + + + V4L2_SLICED_TELETEXT_B (Teletext +System B) + 0x0001 + , + PAL/SECAM line 7-22, 320-335 (second field 7-22) + Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted. + + + V4L2_SLICED_VPS + 0x0400 + + PAL line 16 + Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted. + + + V4L2_SLICED_CAPTION_525 + 0x1000 + + NTSC line 21, 284 (second field 21) + Two bytes in transmission order, including parity +bit, lsb first transmitted. + + + V4L2_SLICED_WSS_625 + 0x4000 + , + PAL/SECAM line 23 + +Byte 0 1 + msb lsb msb lsb +Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 + + + + V4L2_SLICED_VBI_525 + 0x1000 + Set of services applicable to 525 +line systems. + + + V4L2_SLICED_VBI_625 + 0x4401 + Set of services applicable to 625 +line systems. + + + +
+ + + + + &return-value; + + + + EINVAL + + The device does not support sliced VBI capturing or +output, or the value in the type field is +wrong. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-std.xml b/Documentation/DocBook/media/v4l/vidioc-g-std.xml new file mode 100644 index 00000000000..912f8513e5d --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-std.xml @@ -0,0 +1,105 @@ + + + ioctl VIDIOC_G_STD, VIDIOC_S_STD + &manvol; + + + + VIDIOC_G_STD + VIDIOC_S_STD + Query or select the video standard of the current input + + + + + + int ioctl + int fd + int request + v4l2_std_id +*argp + + + + + int ioctl + int fd + int request + const v4l2_std_id +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_STD, VIDIOC_S_STD + + + + argp + + + + + + + + + Description + + To query and select the current video standard applications +use the VIDIOC_G_STD and VIDIOC_S_STD ioctls which take a pointer to a +&v4l2-std-id; type as argument. VIDIOC_G_STD can +return a single flag or a set of flags as in &v4l2-standard; field +id. The flags must be unambiguous such +that they appear in only one enumerated v4l2_standard structure. + + VIDIOC_S_STD accepts one or more +flags, being a write-only ioctl it does not return the actual new standard as +VIDIOC_G_STD does. When no flags are given or +the current input does not support the requested standard the driver +returns an &EINVAL;. When the standard set is ambiguous drivers may +return EINVAL or choose any of the requested +standards. + + + + &return-value; + + + + EINVAL + + This ioctl is not supported, or the +VIDIOC_S_STD parameter was unsuitable. + + + + EBUSY + + The device is busy and therefore can not change the standard + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml b/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml new file mode 100644 index 00000000000..bd98c734c06 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml @@ -0,0 +1,535 @@ + + + ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER + &manvol; + + + + VIDIOC_G_TUNER + VIDIOC_S_TUNER + Get or set tuner attributes + + + + + + int ioctl + int fd + int request + struct v4l2_tuner +*argp + + + + + int ioctl + int fd + int request + const struct v4l2_tuner +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_TUNER, VIDIOC_S_TUNER + + + + argp + + + + + + + + + Description + + To query the attributes of a tuner applications initialize the +index field and zero out the +reserved array of a &v4l2-tuner; and call the +VIDIOC_G_TUNER ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all tuners +applications shall begin at index zero, incrementing by one until the +driver returns EINVAL. + + Tuners have two writable properties, the audio mode and +the radio frequency. To change the audio mode, applications initialize +the index, +audmode and +reserved fields and call the +VIDIOC_S_TUNER ioctl. This will +not change the current tuner, which is determined +by the current video input. Drivers may choose a different audio mode +if the requested mode is invalid or unsupported. Since this is a +write-only ioctl, it does not return the actually +selected audio mode. + + To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available. + + + struct <structname>v4l2_tuner</structname> + + + + + + + + + __u32 + index + Identifies the tuner, set by the +application. + + + __u8 + name[32] + Name of the tuner, a +NUL-terminated ASCII string. This information is intended for the +user. + + + &v4l2-tuner-type; + type + Type of the tuner, see . + + + __u32 + capability + Tuner capability flags, see +. Audio flags indicate the ability +to decode audio subprograms. They will not +change, for example with the current video standard.When +the structure refers to a radio tuner only the +V4L2_TUNER_CAP_LOW, +V4L2_TUNER_CAP_STEREO and +V4L2_TUNER_CAP_RDS flags can be set. + + + __u32 + rangelow + The lowest tunable frequency in +units of 62.5 kHz, or if the capability +flag V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + rangehigh + The highest tunable frequency in +units of 62.5 kHz, or if the capability +flag V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + rxsubchans + Some tuners or audio +decoders can determine the received audio subprograms by analyzing +audio carriers, pilot tones or other indicators. To pass this +information drivers set flags defined in in this field. For +example: + + + + + V4L2_TUNER_SUB_MONO + receiving mono audio + + + + + STEREO | SAP + receiving stereo audio and a secondary audio +program + + + + + MONO | STEREO + receiving mono or stereo audio, the hardware cannot +distinguish + + + + + LANG1 | LANG2 + receiving bilingual audio + + + + + MONO | STEREO | LANG1 | LANG2 + receiving mono, stereo or bilingual +audio + + + + + When the +V4L2_TUNER_CAP_STEREO, +_LANG1, _LANG2 or +_SAP flag is cleared in the +capability field, the corresponding +V4L2_TUNER_SUB_ flag must not be set +here.This field is valid only if this is the tuner of the +current video input, or when the structure refers to a radio +tuner. + + + __u32 + audmode + The selected audio mode, see + for valid values. The audio mode does +not affect audio subprogram detection, and like a control it does not automatically change +unless the requested mode is invalid or unsupported. See for possible results when +the selected and received audio programs do not +match.Currently this is the only field of struct +v4l2_tuner applications can +change. + + + __u32 + signal + The signal strength if known, ranging +from 0 to 65535. Higher values indicate a better signal. + + + __s32 + afc + Automatic frequency control: When the +afc value is negative, the frequency is too +low, when positive too high. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + enum v4l2_tuner_type + + &cs-def; + + + V4L2_TUNER_RADIO + 1 + + + + V4L2_TUNER_ANALOG_TV + 2 + + + + +
+ + + Tuner and Modulator Capability Flags + + &cs-def; + + + V4L2_TUNER_CAP_LOW + 0x0001 + When set, tuning frequencies are expressed in units of +62.5 Hz, otherwise in units of 62.5 kHz. + + + V4L2_TUNER_CAP_NORM + 0x0002 + This is a multi-standard tuner; the video standard +can or must be switched. (B/G PAL tuners for example are typically not + considered multi-standard because the video standard is automatically + determined from the frequency band.) The set of supported video + standards is available from the &v4l2-input; pointing to this tuner, + see the description of ioctl &VIDIOC-ENUMINPUT; for details. Only + V4L2_TUNER_ANALOG_TV tuners can have this capability. + + + V4L2_TUNER_CAP_STEREO + 0x0010 + Stereo audio reception is supported. + + + V4L2_TUNER_CAP_LANG1 + 0x0040 + Reception of the primary language of a bilingual +audio program is supported. Bilingual audio is a feature of +two-channel systems, transmitting the primary language monaural on the +main audio carrier and a secondary language monaural on a second +carrier. Only + V4L2_TUNER_ANALOG_TV tuners can have this capability. + + + V4L2_TUNER_CAP_LANG2 + 0x0020 + Reception of the secondary language of a bilingual +audio program is supported. Only + V4L2_TUNER_ANALOG_TV tuners can have this capability. + + + V4L2_TUNER_CAP_SAP + 0x0020 + Reception of a secondary audio program is +supported. This is a feature of the BTSC system which accompanies the +NTSC video standard. Two audio carriers are available for mono or +stereo transmissions of a primary language, and an independent third +carrier for a monaural secondary language. Only + V4L2_TUNER_ANALOG_TV tuners can have this capability.Note the +V4L2_TUNER_CAP_LANG2 and +V4L2_TUNER_CAP_SAP flags are synonyms. +V4L2_TUNER_CAP_SAP applies when the tuner +supports the V4L2_STD_NTSC_M video +standard. + + + V4L2_TUNER_CAP_RDS + 0x0080 + RDS capture is supported. This capability is only valid for +radio tuners. + + + +
+ + + Tuner Audio Reception Flags + + &cs-def; + + + V4L2_TUNER_SUB_MONO + 0x0001 + The tuner receives a mono audio signal. + + + V4L2_TUNER_SUB_STEREO + 0x0002 + The tuner receives a stereo audio signal. + + + V4L2_TUNER_SUB_LANG1 + 0x0008 + The tuner receives the primary language of a +bilingual audio signal. Drivers must clear this flag when the current +video standard is V4L2_STD_NTSC_M. + + + V4L2_TUNER_SUB_LANG2 + 0x0004 + The tuner receives the secondary language of a +bilingual audio signal (or a second audio program). + + + V4L2_TUNER_SUB_SAP + 0x0004 + The tuner receives a Second Audio Program. Note the +V4L2_TUNER_SUB_LANG2 and +V4L2_TUNER_SUB_SAP flags are synonyms. The +V4L2_TUNER_SUB_SAP flag applies when the +current video standard is V4L2_STD_NTSC_M. + + + V4L2_TUNER_SUB_RDS + 0x0010 + The tuner receives an RDS channel. + + + +
+ + + Tuner Audio Modes + + &cs-def; + + + V4L2_TUNER_MODE_MONO + 0 + Play mono audio. When the tuner receives a stereo +signal this a down-mix of the left and right channel. When the tuner +receives a bilingual or SAP signal this mode selects the primary +language. + + + V4L2_TUNER_MODE_STEREO + 1 + Play stereo audio. When the tuner receives +bilingual audio it may play different languages on the left and right +channel or the primary language is played on both channels.Playing +different languages in this mode is +deprecated. New drivers should do this only in +MODE_LANG1_LANG2.When the tuner +receives no stereo signal or does not support stereo reception the +driver shall fall back to MODE_MONO. + + + V4L2_TUNER_MODE_LANG1 + 3 + Play the primary language, mono or stereo. Only +V4L2_TUNER_ANALOG_TV tuners support this +mode. + + + V4L2_TUNER_MODE_LANG2 + 2 + Play the secondary language, mono. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +V4L2_TUNER_ANALOG_TV tuners support this +mode. + + + V4L2_TUNER_MODE_SAP + 2 + Play the Second Audio Program. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +V4L2_TUNER_ANALOG_TV tuners support this mode. +Note the V4L2_TUNER_MODE_LANG2 and +V4L2_TUNER_MODE_SAP are synonyms. + + + V4L2_TUNER_MODE_LANG1_LANG2 + 4 + Play the primary language on the left channel, the +secondary language on the right channel. When the tuner receives no +bilingual audio or SAP, it shall fall back to +MODE_LANG1 or MODE_MONO. +Only V4L2_TUNER_ANALOG_TV tuners support this +mode. + + + +
+ + + Tuner Audio Matrix + + + + + + + + + + + Selected +V4L2_TUNER_MODE_ + + + Received V4L2_TUNER_SUB_ + MONO + STEREO + LANG1 + LANG2 = SAP + LANG1_LANG2This +mode has been added in Linux 2.6.17 and may not be supported by older +drivers. + + + + + MONO + Mono + Mono/Mono + Mono + Mono + Mono/Mono + + + MONO | SAP + Mono + Mono/Mono + Mono + SAP + Mono/SAP (preferred) or Mono/Mono + + + STEREO + L+R + L/R + Stereo L/R (preferred) or Mono L+R + Stereo L/R (preferred) or Mono L+R + L/R (preferred) or L+R/L+R + + + STEREO | SAP + L+R + L/R + Stereo L/R (preferred) or Mono L+R + SAP + L+R/SAP (preferred) or L/R or L+R/L+R + + + LANG1 | LANG2 + Language 1 + Lang1/Lang2 (deprecatedPlayback of +both languages in MODE_STEREO is deprecated. In +the future drivers should produce only the primary language in this +mode. Applications should request +MODE_LANG1_LANG2 to record both languages or a +stereo signal.) or +Lang1/Lang1 + Language 1 + Language 2 + Lang1/Lang2 (preferred) or Lang1/Lang1 + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-tuner; index is +out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-log-status.xml b/Documentation/DocBook/media/v4l/vidioc-log-status.xml new file mode 100644 index 00000000000..2634b7c88b5 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-log-status.xml @@ -0,0 +1,58 @@ + + + ioctl VIDIOC_LOG_STATUS + &manvol; + + + + VIDIOC_LOG_STATUS + Log driver status information + + + + + + int ioctl + int fd + int request + + + + + + Description + + As the video/audio devices become more complicated it +becomes harder to debug problems. When this ioctl is called the driver +will output the current device status to the kernel log. This is +particular useful when dealing with problems like no sound, no video +and incorrectly tuned channels. Also many modern devices autodetect +video and audio standards and this ioctl will report what the device +thinks what the standard is. Mismatches may give an indication where +the problem is. + + This ioctl is optional and not all drivers support it. It +was introduced in Linux 2.6.15. + + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-overlay.xml b/Documentation/DocBook/media/v4l/vidioc-overlay.xml new file mode 100644 index 00000000000..1036c582cc1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-overlay.xml @@ -0,0 +1,83 @@ + + + ioctl VIDIOC_OVERLAY + &manvol; + + + + VIDIOC_OVERLAY + Start or stop video overlay + + + + + + int ioctl + int fd + int request + const int *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_OVERLAY + + + + argp + + + + + + + + + Description + + This ioctl is part of the video + overlay I/O method. Applications call + VIDIOC_OVERLAY to start or stop the + overlay. It takes a pointer to an integer which must be set to + zero by the application to stop overlay, to one to start. + + Drivers do not support &VIDIOC-STREAMON; or +&VIDIOC-STREAMOFF; with V4L2_BUF_TYPE_VIDEO_OVERLAY. + + + + &return-value; + + + + EINVAL + + Video overlay is not supported, or the +parameters have not been set up. See for the necessary steps. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml new file mode 100644 index 00000000000..f2b11f8a403 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml @@ -0,0 +1,194 @@ + + + ioctl VIDIOC_QBUF, VIDIOC_DQBUF + &manvol; + + + + VIDIOC_QBUF + VIDIOC_DQBUF + Exchange a buffer with the driver + + + + + + int ioctl + int fd + int request + struct v4l2_buffer *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QBUF, VIDIOC_DQBUF + + + + argp + + + + + + + + + Description + + Applications call the VIDIOC_QBUF ioctl +to enqueue an empty (capturing) or filled (output) buffer in the +driver's incoming queue. The semantics depend on the selected I/O +method. + + To enqueue a buffer applications set the type +field of a &v4l2-buffer; to the same buffer type as was previously used +with &v4l2-format; type and &v4l2-requestbuffers; +type. Applications must also set the +index field. Valid index numbers range from +zero to the number of buffers allocated with &VIDIOC-REQBUFS; +(&v4l2-requestbuffers; count) minus one. The +contents of the struct v4l2_buffer returned +by a &VIDIOC-QUERYBUF; ioctl will do as well. When the buffer is +intended for output (type is +V4L2_BUF_TYPE_VIDEO_OUTPUT, +V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, or +V4L2_BUF_TYPE_VBI_OUTPUT) applications must also +initialize the bytesused, +field and +timestamp fields, see for details. +Applications must also set flags to 0. If a driver +supports capturing from specific video inputs and you want to specify a video +input, then flags should be set to +V4L2_BUF_FLAG_INPUT and the field +input must be initialized to the desired input. +The reserved field must be set to 0. When using +the multi-planar API, the +m.planes field must contain a userspace pointer +to a filled-in array of &v4l2-plane; and the length +field must be set to the number of elements in that array. + + + To enqueue a memory mapped +buffer applications set the memory +field to V4L2_MEMORY_MMAP. When +VIDIOC_QBUF is called with a pointer to this +structure the driver sets the +V4L2_BUF_FLAG_MAPPED and +V4L2_BUF_FLAG_QUEUED flags and clears the +V4L2_BUF_FLAG_DONE flag in the +flags field, or it returns an +&EINVAL;. + + To enqueue a user pointer +buffer applications set the memory +field to V4L2_MEMORY_USERPTR, the +m.userptr field to the address of the +buffer and length to its size. When the multi-planar +API is used, m.userptr and +length members of the passed array of &v4l2-plane; +have to be used instead. When VIDIOC_QBUF is called with +a pointer to this structure the driver sets the +V4L2_BUF_FLAG_QUEUED flag and clears the +V4L2_BUF_FLAG_MAPPED and +V4L2_BUF_FLAG_DONE flags in the +flags field, or it returns an error code. +This ioctl locks the memory pages of the buffer in physical memory, +they cannot be swapped out to disk. Buffers remain locked until +dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is +called, or until the device is closed. + + Applications call the VIDIOC_DQBUF +ioctl to dequeue a filled (capturing) or displayed (output) buffer +from the driver's outgoing queue. They just set the +type, memory +and reserved +fields of a &v4l2-buffer; as above, when VIDIOC_DQBUF +is called with a pointer to this structure the driver fills the +remaining fields or returns an error code. The driver may also set +V4L2_BUF_FLAG_ERROR in the flags +field. It indicates a non-critical (recoverable) streaming error. In such case +the application may continue as normal, but should be aware that data in the +dequeued buffer might be corrupted. When using the multi-planar API, the +planes array does not have to be passed; the m.planes +member must be set to NULL in that case. + + By default VIDIOC_DQBUF blocks when no +buffer is in the outgoing queue. When the +O_NONBLOCK flag was given to the &func-open; +function, VIDIOC_DQBUF returns immediately +with an &EAGAIN; when no buffer is available. + + The v4l2_buffer structure is +specified in . + + + + &return-value; + + + + EAGAIN + + Non-blocking I/O has been selected using +O_NONBLOCK and no buffer was in the outgoing +queue. + + + + EINVAL + + The buffer type is not +supported, or the index is out of bounds, +or no buffers have been allocated yet, or the +userptr or +length are invalid. + + + + ENOMEM + + Not enough physical or virtual memory was available to +enqueue a user pointer buffer. + + + + EIO + + VIDIOC_DQBUF failed due to an +internal error. Can also indicate temporary problems like signal +loss. Note the driver might dequeue an (empty) buffer despite +returning an error, or even stop capturing. Reusing such buffer may be unsafe +though and its details (e.g. index) may not be +returned either. It is recommended that drivers indicate recoverable errors +by setting the V4L2_BUF_FLAG_ERROR and returning 0 instead. +In that case the application should be able to safely reuse the buffer and +continue streaming. + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml new file mode 100644 index 00000000000..d272f7ab91b --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml @@ -0,0 +1,87 @@ + + + ioctl VIDIOC_QUERY_DV_PRESET + &manvol; + + + + VIDIOC_QUERY_DV_PRESET + Sense the DV preset received by the current +input + + + + + + int ioctl + int fd + int request + struct v4l2_dv_preset *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERY_DV_PRESET + + + + argp + + + + + + + + + Description + + The hardware may be able to detect the current DV preset +automatically, similar to sensing the video standard. To do so, applications +call VIDIOC_QUERY_DV_PRESET with a pointer to a +&v4l2-dv-preset; type. Once the hardware detects a preset, that preset is +returned in the preset field of &v4l2-dv-preset;. If the preset could not be +detected because there was no signal, or the signal was unreliable, or the +signal did not map to a supported preset, then the value V4L2_DV_INVALID is +returned. + + + + &return-value; + + + EINVAL + + This ioctl is not supported. + + + + EBUSY + + The device is busy and therefore can not sense the preset + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml new file mode 100644 index 00000000000..5c104d42d31 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml @@ -0,0 +1,110 @@ + + + ioctl VIDIOC_QUERYBUF + &manvol; + + + + VIDIOC_QUERYBUF + Query the status of a buffer + + + + + + int ioctl + int fd + int request + struct v4l2_buffer *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYBUF + + + + argp + + + + + + + + + Description + + This ioctl is part of the memory +mapping I/O method. It can be used to query the status of a +buffer at any time after buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl. + + Applications set the type field + of a &v4l2-buffer; to the same buffer type as was previously used with +&v4l2-format; type and &v4l2-requestbuffers; +type, and the index + field. Valid index numbers range from zero +to the number of buffers allocated with &VIDIOC-REQBUFS; + (&v4l2-requestbuffers; count) minus one. +The reserved field should to set to 0. +When using the multi-planar API, the +m.planes field must contain a userspace pointer to an +array of &v4l2-plane; and the length field has +to be set to the number of elements in that array. +After calling VIDIOC_QUERYBUF with a pointer to + this structure drivers return an error code or fill the rest of +the structure. + + In the flags field the +V4L2_BUF_FLAG_MAPPED, +V4L2_BUF_FLAG_QUEUED and +V4L2_BUF_FLAG_DONE flags will be valid. The +memory field will be set to the current +I/O method. For the single-planar API, the m.offset +contains the offset of the buffer from the start of the device memory, +the length field its size. For the multi-planar API, +fields m.mem_offset and +length in the m.planes +array elements will be used instead. The driver may or may not set the remaining +fields and flags, they are meaningless in this context. + + The v4l2_buffer structure is + specified in . + + + + &return-value; + + + + EINVAL + + The buffer type is not +supported, or the index is out of bounds. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml new file mode 100644 index 00000000000..f29f1b86213 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -0,0 +1,303 @@ + + + ioctl VIDIOC_QUERYCAP + &manvol; + + + + VIDIOC_QUERYCAP + Query device capabilities + + + + + + int ioctl + int fd + int request + struct v4l2_capability *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYCAP + + + + argp + + + + + + + + + Description + + All V4L2 devices support the +VIDIOC_QUERYCAP ioctl. It is used to identify +kernel devices compatible with this specification and to obtain +information about driver and hardware capabilities. The ioctl takes a +pointer to a &v4l2-capability; which is filled by the driver. When the +driver is not compatible with this specification the ioctl returns an +&EINVAL;. + + + struct <structname>v4l2_capability</structname> + + &cs-str; + + + __u8 + driver[16] + Name of the driver, a unique NUL-terminated +ASCII string. For example: "bttv". Driver specific applications can +use this information to verify the driver identity. It is also useful +to work around known bugs, or to identify drivers in error reports. +The driver version is stored in the version +field.Storing strings in fixed sized arrays is bad +practice but unavoidable here. Drivers and applications should take +precautions to never read or write beyond the end of the array and to +make sure the strings are properly NUL-terminated. + + + __u8 + card[32] + Name of the device, a NUL-terminated ASCII string. +For example: "Yoyodyne TV/FM". One driver may support different brands +or models of video hardware. This information is intended for users, +for example in a menu of available devices. Since multiple TV cards of +the same brand may be installed which are supported by the same +driver, this name should be combined with the character device file +name (⪚ /dev/video2) or the +bus_info string to avoid +ambiguities. + + + __u8 + bus_info[32] + Location of the device in the system, a +NUL-terminated ASCII string. For example: "PCI Slot 4". This +information is intended for users, to distinguish multiple +identical devices. If no such information is available the field may +simply count the devices controlled by the driver, or contain the +empty string (bus_info[0] = 0). + + + __u32 + version + Version number of the driver. Together with +the driver field this identifies a +particular driver. The version number is formatted using the +KERNEL_VERSION() macro: + + + + +#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) + +__u32 version = KERNEL_VERSION(0, 8, 1); + +printf ("Version: %u.%u.%u\n", + (version >> 16) & 0xFF, + (version >> 8) & 0xFF, + version & 0xFF); + + + + __u32 + capabilities + Device capabilities, see . + + + __u32 + reserved[4] + Reserved for future extensions. Drivers must set +this array to zero. + + + +
+ + + Device Capabilities Flags + + &cs-def; + + + V4L2_CAP_VIDEO_CAPTURE + 0x00000001 + The device supports the single-planar API through the Video Capture interface. + + + V4L2_CAP_VIDEO_CAPTURE_MPLANE + 0x00001000 + The device supports the + multi-planar API through the + Video Capture interface. + + + V4L2_CAP_VIDEO_OUTPUT + 0x00000002 + The device supports the single-planar API through the Video Output interface. + + + V4L2_CAP_VIDEO_OUTPUT_MPLANE + 0x00002000 + The device supports the + multi-planar API through the + Video Output interface. + + + V4L2_CAP_VIDEO_OVERLAY + 0x00000004 + The device supports the Video Overlay interface. A video overlay device +typically stores captured images directly in the video memory of a +graphics card, with hardware clipping and scaling. + + + V4L2_CAP_VBI_CAPTURE + 0x00000010 + The device supports the Raw +VBI Capture interface, providing Teletext and Closed Caption +data. + + + V4L2_CAP_VBI_OUTPUT + 0x00000020 + The device supports the Raw VBI Output interface. + + + V4L2_CAP_SLICED_VBI_CAPTURE + 0x00000040 + The device supports the Sliced VBI Capture interface. + + + V4L2_CAP_SLICED_VBI_OUTPUT + 0x00000080 + The device supports the Sliced VBI Output interface. + + + V4L2_CAP_RDS_CAPTURE + 0x00000100 + The device supports the RDS capture interface. + + + V4L2_CAP_VIDEO_OUTPUT_OVERLAY + 0x00000200 + The device supports the Video +Output Overlay (OSD) interface. Unlike the Video +Overlay interface, this is a secondary function of video +output devices and overlays an image onto an outgoing video signal. +When the driver sets this flag, it must clear the +V4L2_CAP_VIDEO_OVERLAY flag and vice +versa.The &v4l2-framebuffer; lacks an +&v4l2-buf-type; field, therefore the type of overlay is implied by the +driver capabilities. + + + V4L2_CAP_HW_FREQ_SEEK + 0x00000400 + The device supports the &VIDIOC-S-HW-FREQ-SEEK; ioctl for +hardware frequency seeking. + + + V4L2_CAP_RDS_OUTPUT + 0x00000800 + The device supports the RDS output interface. + + + V4L2_CAP_TUNER + 0x00010000 + The device has some sort of tuner to +receive RF-modulated video signals. For more information about +tuner programming see +. + + + V4L2_CAP_AUDIO + 0x00020000 + The device has audio inputs or outputs. It may or +may not support audio recording or playback, in PCM or compressed +formats. PCM audio support must be implemented as ALSA or OSS +interface. For more information on audio inputs and outputs see . + + + V4L2_CAP_RADIO + 0x00040000 + This is a radio receiver. + + + V4L2_CAP_MODULATOR + 0x00080000 + The device has some sort of modulator to +emit RF-modulated video/audio signals. For more information about +modulator programming see +. + + + V4L2_CAP_READWRITE + 0x01000000 + The device supports the read() and/or write() +I/O methods. + + + V4L2_CAP_ASYNCIO + 0x02000000 + The device supports the asynchronous I/O methods. + + + V4L2_CAP_STREAMING + 0x04000000 + The device supports the streaming I/O method. + + + +
+ + + + &return-value; + + + + EINVAL + + The device is not compatible with this +specification. + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml new file mode 100644 index 00000000000..0d5e8283cf3 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml @@ -0,0 +1,434 @@ + + + ioctl VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU + &manvol; + + + + VIDIOC_QUERYCTRL + VIDIOC_QUERYMENU + Enumerate controls and menu control items + + + + + + int ioctl + int fd + int request + struct v4l2_queryctrl *argp + + + + + int ioctl + int fd + int request + struct v4l2_querymenu *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU + + + + argp + + + + + + + + + Description + + To query the attributes of a control applications set the +id field of a &v4l2-queryctrl; and call the +VIDIOC_QUERYCTRL ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the id is invalid. + + It is possible to enumerate controls by calling +VIDIOC_QUERYCTRL with successive +id values starting from +V4L2_CID_BASE up to and exclusive +V4L2_CID_BASE_LASTP1. Drivers may return +EINVAL if a control in this range is not +supported. Further applications can enumerate private controls, which +are not defined in this specification, by starting at +V4L2_CID_PRIVATE_BASE and incrementing +id until the driver returns +EINVAL. + + In both cases, when the driver sets the +V4L2_CTRL_FLAG_DISABLED flag in the +flags field this control is permanently +disabled and should be ignored by the application. + V4L2_CTRL_FLAG_DISABLED was +intended for two purposes: Drivers can skip predefined controls not +supported by the hardware (although returning EINVAL would do as +well), or disable predefined and private controls after hardware +detection without the trouble of reordering control arrays and indices +(EINVAL cannot be used to skip private controls because it would +prematurely end the enumeration). + + When the application ORs id with +V4L2_CTRL_FLAG_NEXT_CTRL the driver returns the +next supported control, or EINVAL if there is +none. Drivers which do not support this flag yet always return +EINVAL. + + Additional information is required for menu controls: the +names of the menu items. To query them applications set the +id and index +fields of &v4l2-querymenu; and call the +VIDIOC_QUERYMENU ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the id or +index is invalid. Menu items are enumerated +by calling VIDIOC_QUERYMENU with successive +index values from &v4l2-queryctrl; +minimum to +maximum, inclusive. Note that it is possible +for VIDIOC_QUERYMENU to return an &EINVAL; for some +indices between minimum and maximum. +In that case that particular menu item is not supported by this driver. Also note that +the minimum value is not necessarily 0. + + See also the examples in . + + + struct <structname>v4l2_queryctrl</structname> + + &cs-str; + + + __u32 + id + Identifies the control, set by the application. See + for predefined IDs. When the ID is ORed +with V4L2_CTRL_FLAG_NEXT_CTRL the driver clears the flag and returns +the first control with a higher ID. Drivers which do not support this +flag yet always return an &EINVAL;. + + + &v4l2-ctrl-type; + type + Type of control, see . + + + __u8 + name[32] + Name of the control, a NUL-terminated ASCII +string. This information is intended for the user. + + + __s32 + minimum + Minimum value, inclusive. This field gives a lower +bound for V4L2_CTRL_TYPE_INTEGER controls and the +lowest valid index for V4L2_CTRL_TYPE_MENU controls. +For V4L2_CTRL_TYPE_STRING controls the minimum value +gives the minimum length of the string. This length does not include the terminating +zero. It may not be valid for any other type of control, including +V4L2_CTRL_TYPE_INTEGER64 controls. Note that this is a +signed value. + + + __s32 + maximum + Maximum value, inclusive. This field gives an upper +bound for V4L2_CTRL_TYPE_INTEGER controls and the +highest valid index for V4L2_CTRL_TYPE_MENU +controls. +For V4L2_CTRL_TYPE_STRING controls the maximum value +gives the maximum length of the string. This length does not include the terminating +zero. It may not be valid for any other type of control, including +V4L2_CTRL_TYPE_INTEGER64 controls. Note that this is a +signed value. + + + __s32 + step + This field gives a step size for +V4L2_CTRL_TYPE_INTEGER controls. For +V4L2_CTRL_TYPE_STRING controls this field refers to +the string length that has to be a multiple of this step size. +It may not be valid for any other type of control, including +V4L2_CTRL_TYPE_INTEGER64 +controls.Generally drivers should not scale hardware +control values. It may be necessary for example when the +name or id imply +a particular unit and the hardware actually accepts only multiples of +said unit. If so, drivers must take care values are properly rounded +when scaling, such that errors will not accumulate on repeated +read-write cycles.This field gives the smallest change of +an integer control actually affecting hardware. Often the information +is needed when the user can change controls by keyboard or GUI +buttons, rather than a slider. When for example a hardware register +accepts values 0-511 and the driver reports 0-65535, step should be +128.Note that although signed, the step value is supposed to +be always positive. + + + __s32 + default_value + The default value of a +V4L2_CTRL_TYPE_INTEGER, +_BOOLEAN or _MENU control. +Not valid for other types of controls. Drivers reset controls only +when the driver is loaded, not later, in particular not when the +func-open; is called. + + + __u32 + flags + Control flags, see . + + + __u32 + reserved[2] + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + struct <structname>v4l2_querymenu</structname> + + &cs-str; + + + __u32 + id + Identifies the control, set by the application +from the respective &v4l2-queryctrl; +id. + + + __u32 + index + Index of the menu item, starting at zero, set by + the application. + + + __u8 + name[32] + Name of the menu item, a NUL-terminated ASCII +string. This information is intended for the user. + + + __u32 + reserved + Reserved for future extensions. Drivers must set +the array to zero. + + + +
+ + + enum v4l2_ctrl_type + + + + + + + + + Type + minimum + step + maximum + Description + + + + + V4L2_CTRL_TYPE_INTEGER + any + any + any + An integer-valued control ranging from minimum to +maximum inclusive. The step value indicates the increment between +values which are actually different on the hardware. + + + V4L2_CTRL_TYPE_BOOLEAN + 0 + 1 + 1 + A boolean-valued control. Zero corresponds to +"disabled", and one means "enabled". + + + V4L2_CTRL_TYPE_MENU + ≥ 0 + 1 + N-1 + The control has a menu of N choices. The names of +the menu items can be enumerated with the +VIDIOC_QUERYMENU ioctl. + + + V4L2_CTRL_TYPE_BUTTON + 0 + 0 + 0 + A control which performs an action when set. +Drivers must ignore the value passed with +VIDIOC_S_CTRL and return an &EINVAL; on a +VIDIOC_G_CTRL attempt. + + + V4L2_CTRL_TYPE_INTEGER64 + n/a + n/a + n/a + A 64-bit integer valued control. Minimum, maximum +and step size cannot be queried. + + + V4L2_CTRL_TYPE_STRING + ≥ 0 + ≥ 1 + ≥ 0 + The minimum and maximum string lengths. The step size +means that the string must be (minimum + N * step) characters long for +N ≥ 0. These lengths do not include the terminating zero, so in order to +pass a string of length 8 to &VIDIOC-S-EXT-CTRLS; you need to set the +size field of &v4l2-ext-control; to 9. For &VIDIOC-G-EXT-CTRLS; you can +set the size field to maximum + 1. +Which character encoding is used will depend on the string control itself and +should be part of the control documentation. + + + V4L2_CTRL_TYPE_CTRL_CLASS + n/a + n/a + n/a + This is not a control. When +VIDIOC_QUERYCTRL is called with a control ID +equal to a control class code (see ) + 1, the +ioctl returns the name of the control class and this control type. +Older drivers which do not support this feature return an +&EINVAL;. + + + +
+ + + Control Flags + + &cs-def; + + + V4L2_CTRL_FLAG_DISABLED + 0x0001 + This control is permanently disabled and should be +ignored by the application. Any attempt to change the control will +result in an &EINVAL;. + + + V4L2_CTRL_FLAG_GRABBED + 0x0002 + This control is temporarily unchangeable, for +example because another application took over control of the +respective resource. Such controls may be displayed specially in a +user interface. Attempts to change the control may result in an +&EBUSY;. + + + V4L2_CTRL_FLAG_READ_ONLY + 0x0004 + This control is permanently readable only. Any +attempt to change the control will result in an &EINVAL;. + + + V4L2_CTRL_FLAG_UPDATE + 0x0008 + A hint that changing this control may affect the +value of other controls within the same control class. Applications +should update their user interface accordingly. + + + V4L2_CTRL_FLAG_INACTIVE + 0x0010 + This control is not applicable to the current +configuration and should be displayed accordingly in a user interface. +For example the flag may be set on a MPEG audio level 2 bitrate +control when MPEG audio encoding level 1 was selected with another +control. + + + V4L2_CTRL_FLAG_SLIDER + 0x0020 + A hint that this control is best represented as a +slider-like element in a user interface. + + + V4L2_CTRL_FLAG_WRITE_ONLY + 0x0040 + This control is permanently writable only. Any +attempt to read the control will result in an &EACCES; error code. This +flag is typically present for relative controls or action controls where +writing a value will cause the device to carry out a given action +(⪚ motor control) but no meaningful value can be returned. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-queryctrl; id +is invalid. The &v4l2-querymenu; id is +invalid or index is out of range (less than +minimum or greater than maximum) +or this particular menu item is not supported by the driver. + + + + EACCES + + An attempt was made to read a write-only control. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-querystd.xml b/Documentation/DocBook/media/v4l/vidioc-querystd.xml new file mode 100644 index 00000000000..1a9e6039309 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querystd.xml @@ -0,0 +1,89 @@ + + + ioctl VIDIOC_QUERYSTD + &manvol; + + + + VIDIOC_QUERYSTD + Sense the video standard received by the current +input + + + + + + int ioctl + int fd + int request + v4l2_std_id *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYSTD + + + + argp + + + + + + + + + Description + + The hardware may be able to detect the current video +standard automatically. To do so, applications call +VIDIOC_QUERYSTD with a pointer to a &v4l2-std-id; type. The +driver stores here a set of candidates, this can be a single flag or a +set of supported standards if for example the hardware can only +distinguish between 50 and 60 Hz systems. When detection is not +possible or fails, the set must contain all standards supported by the +current video input or output. + + + + + &return-value; + + + + EINVAL + + This ioctl is not supported. + + + + EBUSY + + The device is busy and therefore can not detect the standard + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml new file mode 100644 index 00000000000..69800ae2334 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml @@ -0,0 +1,150 @@ + + + ioctl VIDIOC_REQBUFS + &manvol; + + + + VIDIOC_REQBUFS + Initiate Memory Mapping or User Pointer I/O + + + + + + int ioctl + int fd + int request + struct v4l2_requestbuffers *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_REQBUFS + + + + argp + + + + + + + + + Description + + This ioctl is used to initiate memory +mapped or user pointer +I/O. Memory mapped buffers are located in device memory and must be +allocated with this ioctl before they can be mapped into the +application's address space. User buffers are allocated by +applications themselves, and this ioctl is merely used to switch the +driver into user pointer I/O mode and to setup some internal structures. + + To allocate device buffers applications initialize all +fields of the v4l2_requestbuffers structure. +They set the type field to the respective +stream or buffer type, the count field to +the desired number of buffers, memory +must be set to the requested I/O method and the reserved array +must be zeroed. When the ioctl +is called with a pointer to this structure the driver will attempt to allocate +the requested number of buffers and it stores the actual number +allocated in the count field. It can be +smaller than the number requested, even zero, when the driver runs out +of free memory. A larger number is also possible when the driver requires +more buffers to function correctly. For example video output requires at least two buffers, +one displayed and one filled by the application. + When the I/O method is not supported the ioctl +returns an &EINVAL;. + + Applications can call VIDIOC_REQBUFS +again to change the number of buffers, however this cannot succeed +when any buffers are still mapped. A count +value of zero frees all buffers, after aborting or finishing any DMA +in progress, an implicit &VIDIOC-STREAMOFF;. + + + struct <structname>v4l2_requestbuffers</structname> + + &cs-str; + + + __u32 + count + The number of buffers requested or granted. + + + &v4l2-buf-type; + type + Type of the stream or buffers, this is the same +as the &v4l2-format; type field. See for valid values. + + + &v4l2-memory; + memory + Applications set this field to +V4L2_MEMORY_MMAP or +V4L2_MEMORY_USERPTR. + + + __u32 + reserved[2] + A place holder for future extensions and custom +(driver defined) buffer types V4L2_BUF_TYPE_PRIVATE and +higher. This array should be zeroed by applications. + + + +
+ + + + &return-value; + + + + EBUSY + + The driver supports multiple opens and I/O is already +in progress, or reallocation of buffers was attempted although one or +more are still mapped. + + + + EINVAL + + The buffer type (type field) or the +requested I/O method (memory) is not +supported. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml new file mode 100644 index 00000000000..c30dcc4232c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml @@ -0,0 +1,135 @@ + + + ioctl VIDIOC_S_HW_FREQ_SEEK + &manvol; + + + + VIDIOC_S_HW_FREQ_SEEK + Perform a hardware frequency seek + + + + + + int ioctl + int fd + int request + struct v4l2_hw_freq_seek +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_S_HW_FREQ_SEEK + + + + argp + + + + + + + + + Description + + Start a hardware frequency seek from the current frequency. +To do this applications initialize the tuner, +type, seek_upward, +spacing and +wrap_around fields, and zero out the +reserved array of a &v4l2-hw-freq-seek; and +call the VIDIOC_S_HW_FREQ_SEEK ioctl with a pointer +to this structure. + + This ioctl is supported if the V4L2_CAP_HW_FREQ_SEEK capability is set. + + + struct <structname>v4l2_hw_freq_seek</structname> + + &cs-str; + + + __u32 + tuner + The tuner index number. This is the +same value as in the &v4l2-input; tuner +field and the &v4l2-tuner; index field. + + + &v4l2-tuner-type; + type + The tuner type. This is the same value as in the +&v4l2-tuner; type field. + + + __u32 + seek_upward + If non-zero, seek upward from the current frequency, else seek downward. + + + __u32 + wrap_around + If non-zero, wrap around when at the end of the frequency range, else stop seeking. + + + __u32 + spacing + If non-zero, defines the hardware seek resolution in Hz. The driver selects the nearest value that is supported by the device. If spacing is zero a reasonable default value is used. + + + __u32 + reserved[7] + Reserved for future extensions. Drivers and + applications must set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + The tuner index is out of +bounds or the value in the type field is +wrong. + + + + EAGAIN + + The ioctl timed-out. Try again. + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml new file mode 100644 index 00000000000..75ed39bf4d2 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-streamon.xml @@ -0,0 +1,115 @@ + + + ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF + &manvol; + + + + VIDIOC_STREAMON + VIDIOC_STREAMOFF + Start or stop streaming I/O + + + + + + int ioctl + int fd + int request + const int *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_STREAMON, VIDIOC_STREAMOFF + + + + argp + + + + + + + + + Description + + The VIDIOC_STREAMON and +VIDIOC_STREAMOFF ioctl start and stop the capture +or output process during streaming (memory +mapping or user pointer) I/O. + + Specifically the capture hardware is disabled and no input +buffers are filled (if there are any empty buffers in the incoming +queue) until VIDIOC_STREAMON has been called. +Accordingly the output hardware is disabled, no video signal is +produced until VIDIOC_STREAMON has been called. +The ioctl will succeed only when at least one output buffer is in the +incoming queue. + + The VIDIOC_STREAMOFF ioctl, apart of +aborting or finishing any DMA in progress, unlocks any user pointer +buffers locked in physical memory, and it removes all buffers from the +incoming and outgoing queues. That means all images captured but not +dequeued yet will be lost, likewise all images enqueued for output but +not transmitted yet. I/O returns to the same state as after calling +&VIDIOC-REQBUFS; and can be restarted accordingly. + + Both ioctls take a pointer to an integer, the desired buffer or +stream type. This is the same as &v4l2-requestbuffers; +type. + + Note applications can be preempted for unknown periods right +before or after the VIDIOC_STREAMON or +VIDIOC_STREAMOFF calls, there is no notion of +starting or stopping "now". Buffer timestamps can be used to +synchronize with other events. + + + + &return-value; + + + + EINVAL + + Streaming I/O is not supported, the buffer +type is not supported, or no buffers have +been allocated (memory mapping) or enqueued (output) yet. + + + + EPIPE + + The driver implements pad-level format configuration and + the pipeline configuration is invalid. + + + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml new file mode 100644 index 00000000000..2f8f4f0a023 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml @@ -0,0 +1,152 @@ + + + ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL + &manvol; + + + + VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL + Enumerate frame intervals + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_frame_interval_enum * + argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + This ioctl lets applications enumerate available frame intervals on a + given sub-device pad. Frame intervals only makes sense for sub-devices that + can control the frame period on their own. This includes, for instance, + image sensors and TV tuners. + + For the common use case of image sensors, the frame intervals + available on the sub-device output pad depend on the frame format and size + on the same pad. Applications must thus specify the desired format and size + when enumerating frame intervals. + + To enumerate frame intervals applications initialize the + index, pad, + code, width and + height fields of + &v4l2-subdev-frame-interval-enum; and call the + VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL ioctl with a pointer + to this structure. Drivers fill the rest of the structure or return + an &EINVAL; if one of the input fields is invalid. All frame intervals are + enumerable by beginning at index zero and incrementing by one until + EINVAL is returned. + + Available frame intervals may depend on the current 'try' formats + at other pads of the sub-device, as well as on the current active links. See + &VIDIOC-SUBDEV-G-FMT; for more information about the try formats. + + Sub-devices that support the frame interval enumeration ioctl should + implemented it on a single pad only. Its behaviour when supported on + multiple pads of the same sub-device is not defined. + + + struct <structname>v4l2_subdev_frame_interval_enum</structname> + + &cs-str; + + + __u32 + index + Number of the format in the enumeration, set by the + application. + + + __u32 + pad + Pad number as reported by the media controller API. + + + __u32 + code + The media bus format code, as defined in + . + + + __u32 + width + Frame width, in pixels. + + + __u32 + height + Frame height, in pixels. + + + &v4l2-fract; + interval + Period, in seconds, between consecutive video frames. + + + __u32 + reserved[9] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-subdev-frame-interval-enum; + pad references a non-existing pad, one of + the code, width + or height fields are invalid for the given + pad or the index field is out of bounds. + + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml new file mode 100644 index 00000000000..79ce42b7c60 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml @@ -0,0 +1,154 @@ + + + ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE + &manvol; + + + + VIDIOC_SUBDEV_ENUM_FRAME_SIZE + Enumerate media bus frame sizes + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_frame_size_enum * + argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_ENUM_FRAME_SIZE + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + This ioctl allows applications to enumerate all frame sizes + supported by a sub-device on the given pad for the given media bus format. + Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE; + ioctl. + + To enumerate frame sizes applications initialize the + pad, code and + index fields of the + &v4l2-subdev-mbus-code-enum; and call the + VIDIOC_SUBDEV_ENUM_FRAME_SIZE ioctl with a pointer to + the structure. Drivers fill the minimum and maximum frame sizes or return + an &EINVAL; if one of the input parameters is invalid. + + Sub-devices that only support discrete frame sizes (such as most + sensors) will return one or more frame sizes with identical minimum and + maximum values. + + Not all possible sizes in given [minimum, maximum] ranges need to be + supported. For instance, a scaler that uses a fixed-point scaling ratio + might not be able to produce every frame size between the minimum and + maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to + try the sub-device for an exact supported frame size. + + Available frame sizes may depend on the current 'try' formats at other + pads of the sub-device, as well as on the current active links and the + current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more + information about try formats. + + + struct <structname>v4l2_subdev_frame_size_enum</structname> + + &cs-str; + + + __u32 + index + Number of the format in the enumeration, set by the + application. + + + __u32 + pad + Pad number as reported by the media controller API. + + + __u32 + code + The media bus format code, as defined in + . + + + __u32 + min_width + Minimum frame width, in pixels. + + + __u32 + max_width + Maximum frame width, in pixels. + + + __u32 + min_height + Minimum frame height, in pixels. + + + __u32 + max_height + Maximum frame height, in pixels. + + + __u32 + reserved[9] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-subdev-frame-size-enum; pad + references a non-existing pad, the code is + invalid for the given pad or the index + field is out of bounds. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml new file mode 100644 index 00000000000..a6b3432449f --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml @@ -0,0 +1,119 @@ + + + ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE + &manvol; + + + + VIDIOC_SUBDEV_ENUM_MBUS_CODE + Enumerate media bus formats + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_mbus_code_enum * + argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_ENUM_MBUS_CODE + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + To enumerate media bus formats available at a given sub-device pad + applications initialize the pad and + index fields of &v4l2-subdev-mbus-code-enum; and + call the VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl with a + pointer to this structure. Drivers fill the rest of the structure or return + an &EINVAL; if either the pad or + index are invalid. All media bus formats are + enumerable by beginning at index zero and incrementing by one until + EINVAL is returned. + + Available media bus formats may depend on the current 'try' formats + at other pads of the sub-device, as well as on the current active links. See + &VIDIOC-SUBDEV-G-FMT; for more information about the try formats. + + + struct <structname>v4l2_subdev_mbus_code_enum</structname> + + &cs-str; + + + __u32 + pad + Pad number as reported by the media controller API. + + + __u32 + index + Number of the format in the enumeration, set by the + application. + + + __u32 + code + The media bus format code, as defined in + . + + + __u32 + reserved[9] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-subdev-mbus-code-enum; pad + references a non-existing pad, or the index + field is out of bounds. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml new file mode 100644 index 00000000000..06197323a8c --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-crop.xml @@ -0,0 +1,155 @@ + + + ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP + &manvol; + + + + VIDIOC_SUBDEV_G_CROP + VIDIOC_SUBDEV_S_CROP + Get or set the crop rectangle on a subdev pad + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_crop *argp + + + + + int ioctl + int fd + int request + const struct v4l2_subdev_crop *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + To retrieve the current crop rectangle applications set the + pad field of a &v4l2-subdev-crop; to the + desired pad number as reported by the media API and the + which field to + V4L2_SUBDEV_FORMAT_ACTIVE. They then call the + VIDIOC_SUBDEV_G_CROP ioctl with a pointer to this + structure. The driver fills the members of the rect + field or returns &EINVAL; if the input arguments are invalid, or if cropping + is not supported on the given pad. + + To change the current crop rectangle applications set both the + pad and which fields + and all members of the rect field. They then call + the VIDIOC_SUBDEV_S_CROP ioctl with a pointer to this + structure. The driver verifies the requested crop rectangle, adjusts it + based on the hardware capabilities and configures the device. Upon return + the &v4l2-subdev-crop; contains the current format as would be returned + by a VIDIOC_SUBDEV_G_CROP call. + + Applications can query the device capabilities by setting the + which to + V4L2_SUBDEV_FORMAT_TRY. When set, 'try' crop + rectangles are not applied to the device by the driver, but are mangled + exactly as active crop rectangles and stored in the sub-device file handle. + Two applications querying the same sub-device would thus not interact with + each other. + + Drivers must not return an error solely because the requested crop + rectangle doesn't match the device capabilities. They must instead modify + the rectangle to match what the hardware can provide. The modified format + should be as close as possible to the original request. + + + struct <structname>v4l2_subdev_crop</structname> + + &cs-str; + + + __u32 + pad + Pad number as reported by the media framework. + + + __u32 + which + Crop rectangle to get or set, from + &v4l2-subdev-format-whence;. + + + &v4l2-rect; + rect + Crop rectangle boundaries, in pixels. + + + __u32 + reserved[8] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + + &return-value; + + + + EBUSY + + The crop rectangle can't be changed because the pad is currently + busy. This can be caused, for instance, by an active video stream on + the pad. The ioctl must not be retried without performing another + action to fix the problem first. Only returned by + VIDIOC_SUBDEV_S_CROP + + + + EINVAL + + The &v4l2-subdev-crop; pad + references a non-existing pad, the which + field references a non-existing format, or cropping is not supported + on the given subdev pad. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml new file mode 100644 index 00000000000..f367c570c53 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml @@ -0,0 +1,180 @@ + + + ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT + &manvol; + + + + VIDIOC_SUBDEV_G_FMT + VIDIOC_SUBDEV_S_FMT + Get or set the data format on a subdev pad + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_format *argp + + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + These ioctls are used to negotiate the frame format at specific + subdev pads in the image pipeline. + + To retrieve the current format applications set the + pad field of a &v4l2-subdev-format; to the + desired pad number as reported by the media API and the + which field to + V4L2_SUBDEV_FORMAT_ACTIVE. When they call the + VIDIOC_SUBDEV_G_FMT ioctl with a pointer to this + structure the driver fills the members of the format + field. + + To change the current format applications set both the + pad and which fields + and all members of the format field. When they + call the VIDIOC_SUBDEV_S_FMT ioctl with a pointer to this + structure the driver verifies the requested format, adjusts it based on the + hardware capabilities and configures the device. Upon return the + &v4l2-subdev-format; contains the current format as would be returned by a + VIDIOC_SUBDEV_G_FMT call. + + Applications can query the device capabilities by setting the + which to + V4L2_SUBDEV_FORMAT_TRY. When set, 'try' formats are not + applied to the device by the driver, but are changed exactly as active + formats and stored in the sub-device file handle. Two applications querying + the same sub-device would thus not interact with each other. + + For instance, to try a format at the output pad of a sub-device, + applications would first set the try format at the sub-device input with the + VIDIOC_SUBDEV_S_FMT ioctl. They would then either + retrieve the default format at the output pad with the + VIDIOC_SUBDEV_G_FMT ioctl, or set the desired output + pad format with the VIDIOC_SUBDEV_S_FMT ioctl and check + the returned value. + + Try formats do not depend on active formats, but can depend on the + current links configuration or sub-device controls value. For instance, a + low-pass noise filter might crop pixels at the frame boundaries, modifying + its output frame size. + + Drivers must not return an error solely because the requested format + doesn't match the device capabilities. They must instead modify the format + to match what the hardware can provide. The modified format should be as + close as possible to the original request. + + + struct <structname>v4l2_subdev_format</structname> + + &cs-str; + + + __u32 + pad + Pad number as reported by the media controller API. + + + __u32 + which + Format to modified, from &v4l2-subdev-format-whence;. + + + &v4l2-mbus-framefmt; + format + Definition of an image format, see for details. + + + __u32 + reserved[8] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + enum <structname>v4l2_subdev_format_whence</structname> + + &cs-def; + + + V4L2_SUBDEV_FORMAT_TRY + 0 + Try formats, used for querying device capabilities. + + + V4L2_SUBDEV_FORMAT_ACTIVE + 1 + Active formats, applied to the hardware. + + + +
+ + + + &return-value; + + + + EBUSY + + The format can't be changed because the pad is currently busy. + This can be caused, for instance, by an active video stream on the + pad. The ioctl must not be retried without performing another action + to fix the problem first. Only returned by + VIDIOC_SUBDEV_S_FMT + + + + EINVAL + + The &v4l2-subdev-format; pad + references a non-existing pad, or the which + field references a non-existing format. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml new file mode 100644 index 00000000000..0bc3ea22d31 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-frame-interval.xml @@ -0,0 +1,141 @@ + + + ioctl VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL + &manvol; + + + + VIDIOC_SUBDEV_G_FRAME_INTERVAL + VIDIOC_SUBDEV_S_FRAME_INTERVAL + Get or set the frame interval on a subdev pad + + + + + + int ioctl + int fd + int request + struct v4l2_subdev_frame_interval *argp + + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + These ioctls are used to get and set the frame interval at specific + subdev pads in the image pipeline. The frame interval only makes sense for + sub-devices that can control the frame period on their own. This includes, + for instance, image sensors and TV tuners. Sub-devices that don't support + frame intervals must not implement these ioctls. + + To retrieve the current frame interval applications set the + pad field of a &v4l2-subdev-frame-interval; to + the desired pad number as reported by the media controller API. When they + call the VIDIOC_SUBDEV_G_FRAME_INTERVAL ioctl with a + pointer to this structure the driver fills the members of the + interval field. + + To change the current frame interval applications set both the + pad field and all members of the + interval field. When they call the + VIDIOC_SUBDEV_S_FRAME_INTERVAL ioctl with a pointer to + this structure the driver verifies the requested interval, adjusts it based + on the hardware capabilities and configures the device. Upon return the + &v4l2-subdev-frame-interval; contains the current frame interval as would be + returned by a VIDIOC_SUBDEV_G_FRAME_INTERVAL call. + + + Drivers must not return an error solely because the requested interval + doesn't match the device capabilities. They must instead modify the interval + to match what the hardware can provide. The modified interval should be as + close as possible to the original request. + + Sub-devices that support the frame interval ioctls should implement + them on a single pad only. Their behaviour when supported on multiple pads + of the same sub-device is not defined. + + + struct <structname>v4l2_subdev_frame_interval</structname> + + &cs-str; + + + __u32 + pad + Pad number as reported by the media controller API. + + + &v4l2-fract; + interval + Period, in seconds, between consecutive video frames. + + + __u32 + reserved[9] + Reserved for future extensions. Applications and drivers must + set the array to zero. + + + +
+ + + + &return-value; + + + + EBUSY + + The frame interval can't be changed because the pad is currently + busy. This can be caused, for instance, by an active video stream on + the pad. The ioctl must not be retried without performing another + action to fix the problem first. Only returned by + VIDIOC_SUBDEV_S_FRAME_INTERVAL + + + + EINVAL + + The &v4l2-subdev-frame-interval; pad + references a non-existing pad, or the pad doesn't support frame + intervals. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml new file mode 100644 index 00000000000..8b501791aa6 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -0,0 +1,133 @@ + + + ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + &manvol; + + + + VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + Subscribe or unsubscribe event + + + + + + int ioctl + int fd + int request + struct v4l2_event_subscription +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + + + + argp + + + + + + + + + Description + + Subscribe or unsubscribe V4L2 event. Subscribed events are + dequeued by using the &VIDIOC-DQEVENT; ioctl. + + + struct <structname>v4l2_event_subscription</structname> + + &cs-str; + + + __u32 + type + Type of the event. + + + __u32 + reserved[7] + Reserved for future extensions. Drivers and applications + must set the array to zero. + + + +
+ + + Event Types + + &cs-def; + + + V4L2_EVENT_ALL + 0 + All events. V4L2_EVENT_ALL is valid only for + VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once. + + + + V4L2_EVENT_VSYNC + 1 + This event is triggered on the vertical sync. + This event has &v4l2-event-vsync; associated with it. + + + + V4L2_EVENT_EOS + 2 + This event is triggered when the end of a stream is reached. + This is typically used with MPEG decoders to report to the application + when the last of the MPEG stream has been decoded. + + + + V4L2_EVENT_PRIVATE_START + 0x08000000 + Base event number for driver-private events. + + + +
+ + + struct <structname>v4l2_event_vsync</structname> + + &cs-str; + + + __u8 + field + The upcoming field. See &v4l2-field;. + + + +
+ + + + -- cgit v1.2.3 From 82f7b59cb80679038e8e3a99738cce5e094f69b6 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Sun, 15 May 2011 12:33:58 -0300 Subject: [media] v4l: Document EACCES in VIDIOC_[GS]_CTRL and VIDIOC_{G, S, TRY}_EXT_CTRLS VIDIOC_S_CTRL and VIDIOC_S_EXT_CTRLS return EACCES when setting a read-only control VIDIOC_TRY_EXT_CTRLS when trying a read-only control and VIDIOC_G_CTRL and VIDIOC_G_EXT_CTRLS when getting a write-only control. Document this. Signed-off-by: Sakari Ailus Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml | 7 +++++++ Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 7 +++++++ 2 files changed, 14 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml index 8b5e6ff7f3d..5146d00782e 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-ctrl.xml @@ -117,6 +117,13 @@ because another applications took over control of the device function this control belongs to. + + EACCES + + Attempt to set a read-only control or to get a + write-only control. + + diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml index 3aa7f8f9ff0..5e73517fa23 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -294,6 +294,13 @@ The field size is set to a value that is enough to store the payload and this error code is returned. + + EACCES + + Attempt to try or set a read-only control or to get a + write-only control. + + -- cgit v1.2.3 From 157e03f2d30d78bde0b6778560430e425d4ff7e9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jean-Fran=C3=A7ois=20Moine?= Date: Fri, 3 Jun 2011 03:33:41 -0300 Subject: [media] v4l: Documentation about the JPGL pixel format MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The JPG-Light, AKA Pegasus Lossless JPEG, is used in Divio webcams based on NW 800/801/802 chips. Signed-off-by: Jean-François Moine Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/pixfmt.xml | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index deb660207f9..88e5c212140 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -804,6 +804,12 @@ kernel sources in the file Documentation/video4linux/cx2341x/README.hm 'CPIA' YUV format used by the gspca cpia1 driver. + + V4L2_PIX_FMT_JPGL + 'JPGL' + JPEG-Light format (Pegasus Lossless JPEG) + used in Divio webcams NW 80x. + V4L2_PIX_FMT_SPCA501 'S501' -- cgit v1.2.3 From bd7319dc325ac327ddb3777564361bd4186ecdb6 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 15 Jun 2011 23:13:19 -0300 Subject: [media] DocBook: Use base64 for gif/png files The patch utility doesn't work with non-binary files. This causes some tools to break, like generating tarball targets and the scripts that generate diff patches at http://www.kernel.org/pub/linux/kernel/v2.6/. So, let's convert all binaries to ascii using base64, and add a logic at Makefile to convert them back into binaries at runtime. Reported-by: Randy Dunlap Reported-by: Andrew Morton Reviewed-by: Michal Marek Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/bayer.pdf | Bin 12116 -> 0 bytes Documentation/DocBook/media/v4l/bayer.png | Bin 9725 -> 0 bytes Documentation/DocBook/media/v4l/crop.gif | Bin 5967 -> 0 bytes Documentation/DocBook/media/v4l/fieldseq_bt.gif | Bin 25430 -> 0 bytes Documentation/DocBook/media/v4l/fieldseq_tb.gif | Bin 25323 -> 0 bytes Documentation/DocBook/media/v4l/nv12mt.gif | Bin 2108 -> 0 bytes Documentation/DocBook/media/v4l/nv12mt_example.gif | Bin 6858 -> 0 bytes Documentation/DocBook/media/v4l/pipeline.png | Bin 12130 -> 0 bytes Documentation/DocBook/media/v4l/subdev-formats.xml | 3 --- Documentation/DocBook/media/v4l/vbi_525.gif | Bin 4741 -> 0 bytes Documentation/DocBook/media/v4l/vbi_625.gif | Bin 5095 -> 0 bytes Documentation/DocBook/media/v4l/vbi_hsync.gif | Bin 2400 -> 0 bytes 12 files changed, 3 deletions(-) delete mode 100644 Documentation/DocBook/media/v4l/bayer.pdf delete mode 100644 Documentation/DocBook/media/v4l/bayer.png delete mode 100644 Documentation/DocBook/media/v4l/crop.gif delete mode 100644 Documentation/DocBook/media/v4l/fieldseq_bt.gif delete mode 100644 Documentation/DocBook/media/v4l/fieldseq_tb.gif delete mode 100644 Documentation/DocBook/media/v4l/nv12mt.gif delete mode 100644 Documentation/DocBook/media/v4l/nv12mt_example.gif delete mode 100644 Documentation/DocBook/media/v4l/pipeline.png delete mode 100644 Documentation/DocBook/media/v4l/vbi_525.gif delete mode 100644 Documentation/DocBook/media/v4l/vbi_625.gif delete mode 100644 Documentation/DocBook/media/v4l/vbi_hsync.gif (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/bayer.pdf b/Documentation/DocBook/media/v4l/bayer.pdf deleted file mode 100644 index 905e60e6cd4..00000000000 Binary files a/Documentation/DocBook/media/v4l/bayer.pdf and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/bayer.png b/Documentation/DocBook/media/v4l/bayer.png deleted file mode 100644 index 9b15fb22e81..00000000000 Binary files a/Documentation/DocBook/media/v4l/bayer.png and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/crop.gif b/Documentation/DocBook/media/v4l/crop.gif deleted file mode 100644 index 3b9e7d836d4..00000000000 Binary files a/Documentation/DocBook/media/v4l/crop.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/fieldseq_bt.gif b/Documentation/DocBook/media/v4l/fieldseq_bt.gif deleted file mode 100644 index 60e8569a76c..00000000000 Binary files a/Documentation/DocBook/media/v4l/fieldseq_bt.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/fieldseq_tb.gif b/Documentation/DocBook/media/v4l/fieldseq_tb.gif deleted file mode 100644 index 718492f1cfc..00000000000 Binary files a/Documentation/DocBook/media/v4l/fieldseq_tb.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/nv12mt.gif b/Documentation/DocBook/media/v4l/nv12mt.gif deleted file mode 100644 index ef2d4cf8367..00000000000 Binary files a/Documentation/DocBook/media/v4l/nv12mt.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/nv12mt_example.gif b/Documentation/DocBook/media/v4l/nv12mt_example.gif deleted file mode 100644 index df81d68108e..00000000000 Binary files a/Documentation/DocBook/media/v4l/nv12mt_example.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/pipeline.png b/Documentation/DocBook/media/v4l/pipeline.png deleted file mode 100644 index f19b86c2c24..00000000000 Binary files a/Documentation/DocBook/media/v4l/pipeline.png and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml index 8d3409d2c63..bab70711c7c 100644 --- a/Documentation/DocBook/media/v4l/subdev-formats.xml +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -379,9 +379,6 @@
Bayer Patterns - - - diff --git a/Documentation/DocBook/media/v4l/vbi_525.gif b/Documentation/DocBook/media/v4l/vbi_525.gif deleted file mode 100644 index 5580b690d50..00000000000 Binary files a/Documentation/DocBook/media/v4l/vbi_525.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/vbi_625.gif b/Documentation/DocBook/media/v4l/vbi_625.gif deleted file mode 100644 index 34e3251983c..00000000000 Binary files a/Documentation/DocBook/media/v4l/vbi_625.gif and /dev/null differ diff --git a/Documentation/DocBook/media/v4l/vbi_hsync.gif b/Documentation/DocBook/media/v4l/vbi_hsync.gif deleted file mode 100644 index b02434d3b35..00000000000 Binary files a/Documentation/DocBook/media/v4l/vbi_hsync.gif and /dev/null differ -- cgit v1.2.3 From 3751e32961f22e256de85ebd585597ce5875037a Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Sat, 18 Jun 2011 05:52:21 -0300 Subject: [media] v4l: Fix minor typos in the documentation Signed-off-by: Sylwester Nawrocki Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/media-ioc-enum-links.xml | 2 +- Documentation/DocBook/media/v4l/subdev-formats.xml | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml index d2fc73ef8d5..355df43badc 100644 --- a/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml +++ b/Documentation/DocBook/media/v4l/media-ioc-enum-links.xml @@ -139,7 +139,7 @@ - struct <structname>media_links_desc</structname> + struct <structname>media_link_desc</structname> &cs-str; diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml index bab70711c7c..49c532ebbbb 100644 --- a/Documentation/DocBook/media/v4l/subdev-formats.xml +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -2525,7 +2525,7 @@ Those data formats consist of an ordered sequence of 8-bit bytes obtained from JPEG compression process. Additionally to the - _JPEG prefix the format code is made of + _JPEG postfix the format code is made of the following information. The number of bus samples per entropy encoded byte. -- cgit v1.2.3 From b6dc1bab052891f7cbe158f7146a0f9d55806471 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sat, 25 Jun 2011 14:28:08 -0300 Subject: [media] DocBook/v4l: Remove references to the old V4L1 compat layer The old V4L1 Kernel copatibility layer was removed, but the API spec still says that it is there. Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/compat.xml | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index 9f7cd4f2579..b010ac6bfd2 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -10,12 +10,10 @@ driver writers to port or update their code.The Video For Linux API was first introduced in Linux 2.1 to unify and replace various TV and radio device related interfaces, developed independently by driver writers in prior years. Starting -with Linux 2.5 the much improved V4L2 API replaces the V4L API, -although existing drivers will continue to support V4L applications in -the future, either directly or through the V4L2 compatibility layer in -the videodev kernel module translating ioctls on -the fly. For a transition period not all drivers will support the V4L2 -API. +with Linux 2.5 the much improved V4L2 API replaces the V4L API. +The support for the old V4L calls were removed from Kernel, but the +library supports the conversion of a V4L +API system call into a V4L2 one.
Opening and Closing Devices @@ -84,12 +82,7 @@ not compatible with V4L or V4L2. , device file. V4L2 drivers may support multiple opens, see for details and consequences. - V4L drivers respond to V4L2 ioctls with an &EINVAL;. The -compatibility layer in the V4L2 videodev module -can translate V4L ioctl requests to their V4L2 counterpart, however a -V4L2 driver usually needs more preparation to become fully V4L -compatible. This is covered in more detail in . + V4L drivers respond to V4L2 ioctls with an &EINVAL;.
-- cgit v1.2.3 From c20eb18ce1db6792db69f0574f7e955e9f92a213 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sat, 25 Jun 2011 14:11:52 -0300 Subject: [media] DocBook/v4l: Document the new system-wide version behavior Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/common.xml | 10 +++++++++- Documentation/DocBook/media/v4l/v4l2.xml | 6 ++++++ Documentation/DocBook/media/v4l/vidioc-querycap.xml | 15 +++++++++------ 3 files changed, 24 insertions(+), 7 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/common.xml b/Documentation/DocBook/media/v4l/common.xml index 9028721438d..a86f7a04552 100644 --- a/Documentation/DocBook/media/v4l/common.xml +++ b/Documentation/DocBook/media/v4l/common.xml @@ -236,7 +236,15 @@ important parts of the API. The &VIDIOC-QUERYCAP; ioctl is available to check if the kernel device is compatible with this specification, and to query the functions and I/O -methods supported by the device. Other features can be queried +methods supported by the device. + + Starting with kernel version 3.1, VIDIOC-QUERYCAP will return the +V4L2 API version used by the driver, with generally matches the Kernel version. +There's no need of using &VIDIOC-QUERYCAP; to check if an specific ioctl is +supported, the V4L2 core now returns ENOIOCTLCMD if a driver doesn't provide +support for an ioctl. + + Other features can be queried by calling the respective ioctl, for example &VIDIOC-ENUMINPUT; to learn about the number, types and names of video connectors on the device. Although abstraction is a major objective of this API, the diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index a7fd76d0dac..c5ee3982cff 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -127,6 +127,12 @@ structs, ioctls) must be noted in more detail in the history chapter (compat.xml), along with the possible impact on existing drivers and applications. --> + + 3.1 + 2011-06-27 + mcc, po + Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. + 2.6.39 2011-03-01 diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index f29f1b86213..7aa697323c7 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -67,9 +67,8 @@ driver is not compatible with this specification the ioctl returns an Name of the driver, a unique NUL-terminated ASCII string. For example: "bttv". Driver specific applications can use this information to verify the driver identity. It is also useful -to work around known bugs, or to identify drivers in error reports. -The driver version is stored in the version -field.Storing strings in fixed sized arrays is bad +to work around known bugs, or to identify drivers in error reports. +Storing strings in fixed sized arrays is bad practice but unavoidable here. Drivers and applications should take precautions to never read or write beyond the end of the array and to make sure the strings are properly NUL-terminated. @@ -100,9 +99,13 @@ empty string (bus_info[0] = 0). EINVAL The &v4l2-cropcap; type is -invalid or the ioctl is not supported. This is not permitted for -video capture, output and overlay devices, which must support -VIDIOC_CROPCAP. +invalid. This is not permitted for video capture, output and overlay devices, +which must support VIDIOC_CROPCAP. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml index 4a09e203af0..4ecd966808d 100644 --- a/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml @@ -258,18 +258,9 @@ could not identify it. EINVAL - The driver does not support this ioctl, or the -match_type is invalid. + The match_type is invalid. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml index 980c7f3e2fd..a44aebc7997 100644 --- a/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-register.xml @@ -246,15 +246,6 @@ register. &return-value; - - EINVAL - - The driver does not support this ioctl, or the kernel -was not compiled with the CONFIG_VIDEO_ADV_DEBUG -option, or the match_type is invalid, or the -selected chip or register does not exist. - - EPERM @@ -265,11 +256,3 @@ to execute these ioctls. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml index b8c4f7657d6..7769642ee43 100644 --- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -136,11 +136,7 @@
+ + &return-value; + - diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml index b0dde943825..af7f3f2a36d 100644 --- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml @@ -180,8 +180,7 @@ Pictures, rather than immediately. EINVAL - The driver does not support this ioctl, or the -cmd field is invalid. + The cmd field is invalid. @@ -194,11 +193,3 @@ the encoder was not running. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml index 3c216e113a5..5fd72c4c33e 100644 --- a/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml +++ b/Documentation/DocBook/media/v4l/vidioc-enum-frameintervals.xml @@ -254,17 +254,6 @@ enumerated. &return-value; - - See the description section above for a list of return -values that errno can have. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml index 6afa4542c81..f77a13f486d 100644 --- a/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml +++ b/Documentation/DocBook/media/v4l/vidioc-enum-framesizes.xml @@ -267,16 +267,5 @@ application should zero out all members except for the &return-value; - - See the description section above for a list of return -values that errno can have. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml index 9ae8f2d3a96..ea816ab2e49 100644 --- a/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudio.xml @@ -68,19 +68,9 @@ until the driver returns EINVAL. EINVAL - The number of the audio input is out of bounds, or -there are no audio inputs at all and this ioctl is not -supported. + The number of the audio input is out of bounds. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml index d3d7c0ab17b..2e87cedb0d3 100644 --- a/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml +++ b/Documentation/DocBook/media/v4l/vidioc-enumaudioout.xml @@ -71,19 +71,9 @@ signal to a sound card are not audio outputs in this sense. EINVAL - The number of the audio output is out of bounds, or -there are no audio outputs at all and this ioctl is not -supported. + The number of the audio output is out of bounds. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audio.xml b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml index 65361a8c2b0..d7bb9b3738f 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-audio.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-audio.xml @@ -164,25 +164,9 @@ tuner. No audio inputs combine with the current video input, or the number of the selected audio input is out of bounds or it does -not combine, or there are no audio inputs at all and the ioctl is not -supported. - - - - EBUSY - - I/O is in progress, the input cannot be -switched. +not combine. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml index 3632730c5c6..200a2704a97 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-audioout.xml @@ -130,25 +130,9 @@ applications must set the array to zero. No audio outputs combine with the current video output, or the number of the selected audio output is out of bounds or -it does not combine, or there are no audio outputs at all and the -ioctl is not supported. - - - - EBUSY - - I/O is in progress, the output cannot be -switched. +it does not combine. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml index d235b1dedbe..01a50640dce 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-crop.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml @@ -122,22 +122,5 @@ for &v4l2-cropcap; bounds is used. &return-value; - - - - EINVAL - - Cropping is not supported. - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml index d733721a751..7940c114939 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml @@ -97,14 +97,8 @@ If the preset is not supported, it returns an &EINVAL; - + + + &return-value; - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml index d5ec6abf0ce..4a8648ae9a6 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml @@ -212,12 +212,7 @@ bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_H + + &return-value; + - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml index 9f242e4b294..2aef02c9044 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-enc-index.xml @@ -192,22 +192,5 @@ this mask to obtain the picture coding type. &return-value; - - - - EINVAL - - The driver does not support this ioctl. - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml index e7dda4822f0..055718231bc 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml @@ -445,29 +445,12 @@ by a privileged user to negotiate the parameters for a destructive overlay. - - EBUSY - - The framebuffer parameters cannot be changed at this -time because overlay is already enabled, or capturing is enabled -and the hardware cannot capture and overlay simultaneously. - - EINVAL - The ioctl is not supported or the -VIDIOC_S_FBUF parameters are unsuitable. + The VIDIOC_S_FBUF parameters are unsuitable. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml index a4ae59b664e..17fbda15137 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml @@ -183,30 +183,14 @@ capture and output devices. &return-value; - - EBUSY - - The data format cannot be changed at this -time, for example because I/O is already in progress. - - EINVAL The &v4l2-format; type -field is invalid, the requested buffer type not supported, or -VIDIOC_TRY_FMT was called and is not -supported with this buffer type. +field is invalid, the requested buffer type not supported, or the +format is not supported with this buffer type. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-input.xml b/Documentation/DocBook/media/v4l/vidioc-g-input.xml index ed076e92760..08ae82f131f 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-input.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-input.xml @@ -75,26 +75,9 @@ querying or negotiating any other parameters. EINVAL - The number of the video input is out of bounds, or -there are no video inputs at all and this ioctl is not -supported. - - - - EBUSY - - I/O is in progress, the input cannot be -switched. + The number of the video input is out of bounds. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml index 77394b28741..01ea24b8438 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml @@ -159,22 +159,5 @@ to add them. &return-value; - - - - EINVAL - - This ioctl is not supported. - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-output.xml b/Documentation/DocBook/media/v4l/vidioc-g-output.xml index 3ea8c0ed812..fd45f1c13cc 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-output.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-output.xml @@ -76,25 +76,9 @@ negotiating any other parameters. EINVAL The number of the video output is out of bounds, or -there are no video outputs at all and this ioctl is not -supported. - - - - EBUSY - - I/O is in progress, the output cannot be -switched. +there are no video outputs at all. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-parm.xml b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml index 392aa9e5571..19b1d85dd66 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-parm.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml @@ -311,22 +311,5 @@ excessive motion blur. &return-value; - - - - EINVAL - - This ioctl is not supported. - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-priority.xml b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml index 5fb00197864..8f5e3da7002 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-priority.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-priority.xml @@ -120,8 +120,7 @@ recording. EINVAL - The requested priority value is invalid, or the -driver does not support access priorities. + The requested priority value is invalid. diff --git a/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml index 10e721b1737..71741daaf72 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml @@ -246,19 +246,10 @@ line systems. EINVAL - The device does not support sliced VBI capturing or -output, or the value in the type field is + The value in the type field is wrong. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-g-std.xml b/Documentation/DocBook/media/v4l/vidioc-g-std.xml index 912f8513e5d..37996f25b5d 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-std.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-std.xml @@ -82,14 +82,7 @@ standards. EINVAL - This ioctl is not supported, or the -VIDIOC_S_STD parameter was unsuitable. - - - - EBUSY - - The device is busy and therefore can not change the standard + The VIDIOC_S_STD parameter was unsuitable. diff --git a/Documentation/DocBook/media/v4l/vidioc-log-status.xml b/Documentation/DocBook/media/v4l/vidioc-log-status.xml index 2634b7c88b5..5ded7d35e27 100644 --- a/Documentation/DocBook/media/v4l/vidioc-log-status.xml +++ b/Documentation/DocBook/media/v4l/vidioc-log-status.xml @@ -37,22 +37,5 @@ was introduced in Linux 2.6.15. &return-value; - - - - EINVAL - - The driver does not support this ioctl. - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-overlay.xml b/Documentation/DocBook/media/v4l/vidioc-overlay.xml index 1036c582cc1..250a7de1877 100644 --- a/Documentation/DocBook/media/v4l/vidioc-overlay.xml +++ b/Documentation/DocBook/media/v4l/vidioc-overlay.xml @@ -65,19 +65,10 @@ EINVAL - Video overlay is not supported, or the -parameters have not been set up. See The overlay parameters have not been set up. See for the necessary steps. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml index f2b11f8a403..9caa49af580 100644 --- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml @@ -158,15 +158,6 @@ or no buffers have been allocated yet, or the userptr or length are invalid. - - - ENOMEM - - Not enough physical or virtual memory was available to -enqueue a user pointer buffer. - - - EIO VIDIOC_DQBUF failed due to an @@ -184,11 +175,3 @@ continue streaming. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml index d272f7ab91b..23b17f60421 100644 --- a/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml +++ b/Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml @@ -61,27 +61,5 @@ returned. &return-value; - - - EINVAL - - This ioctl is not supported. - - - - EBUSY - - The device is busy and therefore can not sense the preset - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index 7aa697323c7..e3664d6f2de 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -283,24 +283,5 @@ linkend="mmap">streaming I/O method. &return-value; - - - - EINVAL - - The device is not compatible with this -specification. - - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-querystd.xml b/Documentation/DocBook/media/v4l/vidioc-querystd.xml index 1a9e6039309..4b79c7c04ed 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querystd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querystd.xml @@ -62,28 +62,5 @@ current video input or output. &return-value; - - - - EINVAL - - This ioctl is not supported. - - - - EBUSY - - The device is busy and therefore can not detect the standard - - - - - diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml index 69800ae2334..7be4b1d29b9 100644 --- a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml +++ b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml @@ -121,14 +121,6 @@ higher. This array should be zeroed by applications. &return-value; - - EBUSY - - The driver supports multiple opens and I/O is already -in progress, or reallocation of buffers was attempted although one or -more are still mapped. - - EINVAL @@ -140,11 +132,3 @@ supported. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml index 75ed39bf4d2..81cca456905 100644 --- a/Documentation/DocBook/media/v4l/vidioc-streamon.xml +++ b/Documentation/DocBook/media/v4l/vidioc-streamon.xml @@ -88,9 +88,9 @@ synchronize with other events. EINVAL - Streaming I/O is not supported, the buffer -type is not supported, or no buffers have -been allocated (memory mapping) or enqueued (output) yet. + The buffertype is not supported, + or no buffers have been allocated (memory mapping) or enqueued + (output) yet. @@ -105,11 +105,3 @@ been allocated (memory mapping) or enqueued (output) yet. - - diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml index f367c570c53..a67cde6f8c5 100644 --- a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml +++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml @@ -177,4 +177,7 @@ + + &return-value; + diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml index 25471e8e5da..69c0d8a2a3d 100644 --- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -290,13 +290,8 @@ - + + + &return-value; - -- cgit v1.2.3 From dfcf4f9d97eec997283e41cef2d2b6956c32fecd Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 11:37:58 -0300 Subject: [media] DocBook: Use the generic error code page also for MC API Instead of having their own generic error codes at the MC API, move its section to the generic one and be sure that all media ioctl's will point to it. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/gen-errors.xml | 16 +++++++- .../DocBook/media/v4l/media-func-ioctl.xml | 48 +--------------------- .../DocBook/media/v4l/media-ioc-device-info.xml | 3 +- 3 files changed, 18 insertions(+), 49 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index 6ef476a5401..9bf9ca7f46d 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -5,6 +5,11 @@ &cs-str; + + + EBADF + fd is not a valid open file descriptor. + EBUSY The ioctl can't be handled because the device is busy. This is @@ -14,8 +19,17 @@ must not be retried without performing another action to fix the problem first (typically: stop the stream before retrying). + + EFAULT + fd is not a valid open file descriptor. + EINVAL + One or more of the ioctl parameters are invalid. This is a widely + used error code. See the individual ioctl requests for actual causes. + + + EINVAL or ENOTTY The ioctl is not supported by the driver, actually meaning that the required functionality is not available. @@ -25,7 +39,7 @@ ENOSPC - On USB devices, the stream ioctl's can return this error meaning + On USB devices, the stream ioctl's can return this error, meaning that this request would overcommit the usb bandwidth reserved for periodic transfers (up to 80% of the USB bandwidth). diff --git a/Documentation/DocBook/media/v4l/media-func-ioctl.xml b/Documentation/DocBook/media/v4l/media-func-ioctl.xml index bda8604de15..e0ee285baf1 100644 --- a/Documentation/DocBook/media/v4l/media-func-ioctl.xml +++ b/Documentation/DocBook/media/v4l/media-func-ioctl.xml @@ -63,54 +63,10 @@ - Return Value - - ioctl() returns 0 on - success. On failure, -1 is returned, and the - errno variable is set appropriately. Generic error codes - are listed below, and request-specific error codes are listed in the + &return-value; + Request-specific error codes are listed in the individual requests descriptions. When an ioctl that takes an output or read/write parameter fails, the parameter remains unmodified. - - - - EBADF - - fd is not a valid open file descriptor. - - - - - EFAULT - - argp references an inaccessible memory - area. - - - - EINVAL - - The request or the data pointed to by - argp is not valid. This is a very common error - code, see the individual ioctl requests listed in - for actual causes. - - - - ENOMEM - - Insufficient kernel memory was available to complete the - request. - - - - ENOTTY - - fd is not associated with a character - special device. - - - diff --git a/Documentation/DocBook/media/v4l/media-ioc-device-info.xml b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml index 1f3237351bb..2ce521419e6 100644 --- a/Documentation/DocBook/media/v4l/media-ioc-device-info.xml +++ b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml @@ -127,7 +127,6 @@ - Return value - This function doesn't return specific error codes. + &return-value; -- cgit v1.2.3 From 9e1d50756bad35c7e1b566bed9426f68d93135fd Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 11:39:53 -0300 Subject: [media] DocBook/media-ioc-setup-link.xml: Remove EBUSY The EBUSY is already described as a generic error condition, with a similar text. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/media-ioc-setup-link.xml | 9 --------- 1 file changed, 9 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml index cec97af4dab..fc2e522ee65 100644 --- a/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml +++ b/Documentation/DocBook/media/v4l/media-ioc-setup-link.xml @@ -71,15 +71,6 @@ &return-value; - - EBUSY - - The link properties can't be changed because the link is - currently busy. This can be caused, for instance, by an active media - stream (audio or video) on the link. The ioctl shouldn't be retried if - no other action is performed before to fix the problem. - - EINVAL -- cgit v1.2.3 From 4c14e4a93f02e89e7d0a62604a7652f61057c923 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 11:57:05 -0300 Subject: [media] DocBook: Remove V4L generic error description for ioctl() V4L ioctl function descripton also has a generic error chapter. Remove it, as it is now obsoleted by a general, multi-API generic error descriptions. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/func-ioctl.xml | 72 +--------------------- Documentation/DocBook/media/v4l/gen-errors.xml | 10 ++- .../DocBook/media/v4l/media-func-ioctl.xml | 1 + 3 files changed, 13 insertions(+), 70 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/func-ioctl.xml b/Documentation/DocBook/media/v4l/func-ioctl.xml index b60fd37a629..2de64be706f 100644 --- a/Documentation/DocBook/media/v4l/func-ioctl.xml +++ b/Documentation/DocBook/media/v4l/func-ioctl.xml @@ -64,75 +64,9 @@ their respective function and parameters are specified in - Return Value - - On success the ioctl() function returns -0 and does not reset the -errno variable. On failure --1 is returned, when the ioctl takes an -output or read/write parameter it remains unmodified, and the -errno variable is set appropriately. See below for -possible error codes. Generic errors like EBADF -or EFAULT are not listed in the sections -discussing individual ioctl requests. - Note ioctls may return undefined error codes. Since errors -may have side effects such as a driver reset applications should -abort on unexpected errors. - - - - EBADF - - fd is not a valid open file -descriptor. - - - - EBUSY - - The property cannot be changed right now. Typically -this error code is returned when I/O is in progress or the driver -supports multiple opens and another process locked the property. - - - - EFAULT - - argp references an inaccessible -memory area. - - - - ENOTTY - - fd is not associated with a -character special device. - - - - EINVAL - - The request or the data pointed -to by argp is not valid. This is a very common -error code, see the individual ioctl requests listed in for actual causes. - - - - ENOMEM - - Not enough physical or virtual memory was available to -complete the request. - - - - ERANGE - - The application attempted to set a control with the -&VIDIOC-S-CTRL; ioctl to a value which is out of bounds. - - - + &return-value; + When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified. diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index 9bf9ca7f46d..4268c658652 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -31,7 +31,8 @@ EINVAL or ENOTTY The ioctl is not supported by the driver, actually meaning that - the required functionality is not available. + the required functionality is not available, or the file + descriptor is not for a media device. ENOMEM @@ -46,3 +47,10 @@ + +Note 1: ioctls may return other error codes. Since errors may have side +effects such as a driver reset, applications should abort on unexpected errors. + + +Note 2: Request-specific error codes are listed in the individual +requests descriptions. diff --git a/Documentation/DocBook/media/v4l/media-func-ioctl.xml b/Documentation/DocBook/media/v4l/media-func-ioctl.xml index e0ee285baf1..39478d0fbca 100644 --- a/Documentation/DocBook/media/v4l/media-func-ioctl.xml +++ b/Documentation/DocBook/media/v4l/media-func-ioctl.xml @@ -64,6 +64,7 @@ &return-value; + Request-specific error codes are listed in the individual requests descriptions. When an ioctl that takes an output or read/write parameter fails, -- cgit v1.2.3 From 10dc380f79a9f6f7c34d5a0e92f6b056d9a77d79 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 12:02:12 -0300 Subject: [media] DocBook: Add an error code session for LIRC interface Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/lirc_device_interface.xml | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/lirc_device_interface.xml b/Documentation/DocBook/media/v4l/lirc_device_interface.xml index 0e0453f39e7..a060f3fb6ca 100644 --- a/Documentation/DocBook/media/v4l/lirc_device_interface.xml +++ b/Documentation/DocBook/media/v4l/lirc_device_interface.xml @@ -248,4 +248,8 @@ on working with the default settings initially. + +
+ &return-value; +
-- cgit v1.2.3 From c55d6f8270cab805983aba8cdf1d1980167d3517 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 12:07:54 -0300 Subject: [media] DocBook: Add return error codes to LIRC ioctl session Add a reference for the generic error code chapter to LIRC ioctl description. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/lirc_device_interface.xml | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/lirc_device_interface.xml b/Documentation/DocBook/media/v4l/lirc_device_interface.xml index a060f3fb6ca..8d7eb6bf631 100644 --- a/Documentation/DocBook/media/v4l/lirc_device_interface.xml +++ b/Documentation/DocBook/media/v4l/lirc_device_interface.xml @@ -246,10 +246,8 @@ on working with the default settings initially. - - -
- &return-value; + &return-value; +
-- cgit v1.2.3 From b424f60c5b728c27b0bd719a907847ad4c0e7e59 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 13:18:15 -0300 Subject: [media] DocBook/audio.xml: Remove generic errors Remove generic errors from ioctl() descriptions. For other ioctl's, there's no generic section. So, just keep whatever is there. Also remove the EINTERNAL error code, as no DVB driver returns it, and this error code is not defined on POSIX or on Linux. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/gen-errors.xml | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index 4268c658652..d970f080f88 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -34,6 +34,10 @@ the required functionality is not available, or the file descriptor is not for a media device. + + ENODEV + Device not found or was removed. + ENOMEM There's not enough memory to handle the desired operation. -- cgit v1.2.3 From c1798c90adabf16713086f34a793d89d147022a5 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 5 Jul 2011 13:39:38 -0300 Subject: [media] DocBook/demux.xml: Remove generic errors Remove generic errors from ioctl() descriptions. For other ioctl's, there's no generic section. So, just keep whatever is there. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/gen-errors.xml | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index d970f080f88..c9818799764 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -48,6 +48,11 @@ that this request would overcommit the usb bandwidth reserved for periodic transfers (up to 80% of the USB bandwidth). + + EWOULDBLOCK + Operation would block. Used when the ioctl would need to wait + for an event, but the device was opened in non-blocking mode. + -- cgit v1.2.3 From 66b30b5d510f46c47beb330932afdcb7943d1d78 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 6 Jul 2011 13:42:08 -0300 Subject: [media] DocBook/dvb: Use generic descriptions for the frontend API Move generic stuff into gen-errors.xml, and remove them from DVB API. While here, removes two bogus error codes that aren't supported or used on Linux: EINTERNAL and ENOSIGNAL. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/gen-errors.xml | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index c9818799764..7c1980e8747 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -8,7 +8,7 @@ EBADF - fd is not a valid open file descriptor. + The file descriptor is not a valid. EBUSY @@ -21,18 +21,21 @@ EFAULT - fd is not a valid open file descriptor. + There was a failure while copying data from/to userspace, + probably caused by an invalid pointer reference. EINVAL - One or more of the ioctl parameters are invalid. This is a widely - used error code. See the individual ioctl requests for actual causes. + One or more of the ioctl parameters are invalid or out of the + allowed range. This is a widely used error code. See the individual + ioctl requests for specific causes. EINVAL or ENOTTY The ioctl is not supported by the driver, actually meaning that the required functionality is not available, or the file - descriptor is not for a media device. + descriptor is not for a media device. The usage of EINVAL is + deprecated and will be fixed on a latter patch. ENODEV @@ -48,6 +51,17 @@ that this request would overcommit the usb bandwidth reserved for periodic transfers (up to 80% of the USB bandwidth). + + ENOSYS or EOPNOTSUPP + Function not available for this device (dvb API only. Will likely + be replaced anytime soon by ENOTTY). + + + EPERM + Permission denied. Can be returned if the device needs write + permission, or some special capabilities is needed + (e. g. root) + EWOULDBLOCK Operation would block. Used when the ioctl would need to wait -- cgit v1.2.3 From 9190d191b1b814dfb488125b54cf0de6eedd9220 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 6 Jul 2011 14:08:08 -0300 Subject: [media] v4l2 core: return -ENOTTY if an ioctl doesn't exist Currently, -EINVAL is used to return either when an IOCTL is not implemented, or if the ioctl was not implemented. Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/gen-errors.xml | 13 ++++++------- Documentation/DocBook/media/v4l/v4l2.xml | 2 ++ 2 files changed, 8 insertions(+), 7 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/gen-errors.xml b/Documentation/DocBook/media/v4l/gen-errors.xml index 7c1980e8747..5bbf3ce1973 100644 --- a/Documentation/DocBook/media/v4l/gen-errors.xml +++ b/Documentation/DocBook/media/v4l/gen-errors.xml @@ -30,13 +30,6 @@ allowed range. This is a widely used error code. See the individual ioctl requests for specific causes. - - EINVAL or ENOTTY - The ioctl is not supported by the driver, actually meaning that - the required functionality is not available, or the file - descriptor is not for a media device. The usage of EINVAL is - deprecated and will be fixed on a latter patch. - ENODEV Device not found or was removed. @@ -45,6 +38,12 @@ ENOMEM There's not enough memory to handle the desired operation. + + ENOTTY + The ioctl is not supported by the driver, actually meaning that + the required functionality is not available, or the file + descriptor is not for a media device. + ENOSPC On USB devices, the stream ioctl's can return this error, meaning diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index c5ee3982cff..43386a6aef7 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -132,7 +132,9 @@ applications. --> 2011-06-27 mcc, po Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. + Standardize an error code for invalid ioctl. + 2.6.39 2011-03-01 -- cgit v1.2.3 From 21144ea601f1fea37c7add15a099affec7c08425 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 5 Jun 2011 08:32:27 -0300 Subject: [media] videodev2.h Add SE401 compressed RGB format Signed-off-by: Hans de Goede Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/pixfmt.xml | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index 88e5c212140..804b2e5e080 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -860,6 +860,11 @@ kernel sources in the file Documentation/video4linux/cx2341x/README.hm 'PJPG' Pixart 73xx JPEG format used by the gspca driver. + + V4L2_PIX_FMT_SE401 + 'S401' + Compressed RGB format used by the gspca se401 driver + V4L2_PIX_FMT_SQ905C '905C' -- cgit v1.2.3 From ee490b466162925193c847b02aabd6048ff8cbe9 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Tue, 5 Jul 2011 07:17:39 -0300 Subject: [media] DocBook: fix typo: vl42_plane_pix_format -> v4l2_plane_pix_format Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/pixfmt.xml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index 804b2e5e080..389432d780a 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -121,7 +121,7 @@ set this field to zero. an array of v4l2_plane_pix_format structures, describing all planes of that format. - struct <structname>vl42_plane_pix_format</structname> + struct <structname>v4l2_plane_pix_format</structname> &cs-str; -- cgit v1.2.3 From aec67f054205da77f83ba52f83239225d6cbe366 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 23 May 2011 07:36:55 -0300 Subject: [media] DocBook: document V4L2_CTRL_TYPE_BITMASK [mchehab@redhat.com: Fix a merge conflict and make compat.xml coherent with v4l2.xml] Signed-off-by: Hans Verkuil Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/compat.xml | 10 ++++++++++ Documentation/DocBook/media/v4l/v4l2.xml | 11 ++++++----- Documentation/DocBook/media/v4l/vidioc-queryctrl.xml | 12 +++++++++++- 3 files changed, 27 insertions(+), 6 deletions(-) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index b010ac6bfd2..d7c015e8df8 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2360,6 +2360,16 @@ that used it. It was originally scheduled for removal in 2.6.35. +
+ V4L2 in Linux 3.1 + + + VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. + Standardize an error code for invalid ioctl. + Added V4L2_CTRL_TYPE_BITMASK. + + +
Relation of V4L2 to other Linux multimedia APIs diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index 43386a6aef7..0d05e8747c1 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -87,7 +87,7 @@ Remote Controller chapter. - Pawel + Pawel Osciak Designed and documented the multi-planar API. @@ -130,9 +130,10 @@ applications. --> 3.1 2011-06-27 - mcc, po - Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. - Standardize an error code for invalid ioctl. + mcc, po, hv + Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. + Standardize an error code for invalid ioctl. + Added V4L2_CTRL_TYPE_BITMASK. @@ -409,7 +410,7 @@ and discussions on the V4L mailing list. Video for Linux Two API Specification - Revision 2.6.39 + Revision 3.1 &sub-common; diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml index 0d5e8283cf3..677ea646c29 100644 --- a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml +++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml @@ -156,7 +156,8 @@ signed value. Maximum value, inclusive. This field gives an upper bound for V4L2_CTRL_TYPE_INTEGER controls and the highest valid index for V4L2_CTRL_TYPE_MENU -controls. +controls. For V4L2_CTRL_TYPE_BITMASK controls it is the +set of usable bits. For V4L2_CTRL_TYPE_STRING controls the maximum value gives the maximum length of the string. This length does not include the terminating zero. It may not be valid for any other type of control, including @@ -289,6 +290,15 @@ values which are actually different on the hardware. The control has a menu of N choices. The names of the menu items can be enumerated with the VIDIOC_QUERYMENU ioctl. + + + V4L2_CTRL_TYPE_BITMASK + 0 + n/a + any + A bitmask field. The maximum value is the set of bits that can +be used, all other bits are to be 0. The maximum value is interpreted as a __u32, +allowing the use of bit 31 in the bitmask. V4L2_CTRL_TYPE_BUTTON -- cgit v1.2.3 From 7ba85fa4fdbbe800e92a937ca567120ef32fe49f Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Wed, 4 May 2011 10:45:58 -0300 Subject: [media] v4l: Add flash control documentation Add documentation for V4L2 flash controls. Signed-off-by: Sakari Ailus Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/compat.xml | 3 + Documentation/DocBook/media/v4l/controls.xml | 283 +++++++++++++++++++++ .../DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 7 + 3 files changed, 293 insertions(+) (limited to 'Documentation/DocBook/media/v4l') diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index d7c015e8df8..ce1004a7da5 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2475,6 +2475,9 @@ ioctls. &VIDIOC-DBG-G-CHIP-IDENT; ioctl. + + Flash API. +
diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index a920ee80f64..9155127ed6a 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -2092,6 +2092,289 @@ manually or automatically if set to zero. Unit, range and step are driver-specif For more details about RDS specification, refer to document, from CENELEC. + +
+ Flash Control Reference + + + Experimental + + This is an experimental +interface and may change in the future. + + + + The V4L2 flash controls are intended to provide generic access + to flash controller devices. Flash controller devices are + typically used in digital cameras. + + + + The interface can support both LED and xenon flash devices. As + of writing this, there is no xenon flash driver using this + interface. + + +
+ Supported use cases + +
+ Unsynchronised LED flash (software strobe) + + + Unsynchronised LED flash is controlled directly by the + host as the sensor. The flash must be enabled by the host + before the exposure of the image starts and disabled once + it ends. The host is fully responsible for the timing of + the flash. + + + Example of such device: Nokia N900. +
+ +
+ Synchronised LED flash (hardware strobe) + + + The synchronised LED flash is pre-programmed by the host + (power and timeout) but controlled by the sensor through a + strobe signal from the sensor to the flash. + + + + The sensor controls the flash duration and timing. This + information typically must be made available to the + sensor. + + +
+ +
+ LED flash as torch + + + LED flash may be used as torch in conjunction with another + use case involving camera or individually. + + +
+ +
+ +
+ Flash Control IDs + + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_FLASH_CLASS + class + + + The FLASH class descriptor. + + + V4L2_CID_FLASH_LED_MODE + menu + + + Defines the mode of the flash LED, + the high-power white LED attached to the flash controller. + Setting this control may not be possible in presence of + some faults. See V4L2_CID_FLASH_FAULT. + + + + + + V4L2_FLASH_LED_MODE_NONE + Off. + + + V4L2_FLASH_LED_MODE_FLASH + Flash mode. + + + V4L2_FLASH_LED_MODE_TORCH + Torch mode. See V4L2_CID_FLASH_TORCH_INTENSITY. + + + + + + V4L2_CID_FLASH_STROBE_SOURCE + menu + + Defines the source of the flash LED + strobe. + + + + + + V4L2_FLASH_STROBE_SOURCE_SOFTWARE + The flash strobe is triggered by using + the V4L2_CID_FLASH_STROBE control. + + + V4L2_FLASH_STROBE_SOURCE_EXTERNAL + The flash strobe is triggered by an + external source. Typically this is a sensor, + which makes it possible to synchronises the + flash strobe start to exposure start. + + + + + + V4L2_CID_FLASH_STROBE + button + + + Strobe flash. Valid when + V4L2_CID_FLASH_LED_MODE is set to + V4L2_FLASH_LED_MODE_FLASH and V4L2_CID_FLASH_STROBE_SOURCE + is set to V4L2_FLASH_STROBE_SOURCE_SOFTWARE. Setting this + control may not be possible in presence of some faults. + See V4L2_CID_FLASH_FAULT. + + + V4L2_CID_FLASH_STROBE_STOP + button + + Stop flash strobe immediately. + + + V4L2_CID_FLASH_STROBE_STATUS + boolean + + + Strobe status: whether the flash + is strobing at the moment or not. This is a read-only + control. + + + V4L2_CID_FLASH_TIMEOUT + integer + + + Hardware timeout for flash. The + flash strobe is stopped after this period of time has + passed from the start of the strobe. + + + V4L2_CID_FLASH_INTENSITY + integer + + + Intensity of the flash strobe when + the flash LED is in flash mode + (V4L2_FLASH_LED_MODE_FLASH). The unit should be milliamps + (mA) if possible. + + + V4L2_CID_FLASH_TORCH_INTENSITY + integer + + + Intensity of the flash LED in + torch mode (V4L2_FLASH_LED_MODE_TORCH). The unit should be + milliamps (mA) if possible. Setting this control may not + be possible in presence of some faults. See + V4L2_CID_FLASH_FAULT. + + + V4L2_CID_FLASH_INDICATOR_INTENSITY + integer + + + Intensity of the indicator LED. + The indicator LED may be fully independent of the flash + LED. The unit should be microamps (uA) if possible. + + + V4L2_CID_FLASH_FAULT + bitmask + + + Faults related to the flash. The + faults tell about specific problems in the flash chip + itself or the LEDs attached to it. Faults may prevent + further use of some of the flash controls. In particular, + V4L2_CID_FLASH_LED_MODE is set to V4L2_FLASH_LED_MODE_NONE + if the fault affects the flash LED. Exactly which faults + have such an effect is chip dependent. Reading the faults + resets the control and returns the chip to a usable state + if possible. + + + + + + V4L2_FLASH_FAULT_OVER_VOLTAGE + Flash controller voltage to the flash LED + has exceeded the limit specific to the flash + controller. + + + V4L2_FLASH_FAULT_TIMEOUT + The flash strobe was still on when + the timeout set by the user --- + V4L2_CID_FLASH_TIMEOUT control --- has expired. + Not all flash controllers may set this in all + such conditions. + + + V4L2_FLASH_FAULT_OVER_TEMPERATURE + The flash controller has overheated. + + + V4L2_FLASH_FAULT_SHORT_CIRCUIT + The short circuit protection of the flash + controller has been triggered. + + + + + + V4L2_CID_FLASH_CHARGE + boolean + + Enable or disable charging of the xenon + flash capacitor. + + + V4L2_CID_FLASH_READY + boolean + + + Is the flash ready to strobe? + Xenon flashes require their capacitors charged before + strobing. LED flashes often require a cooldown period + after strobe during which another strobe will not be + possible. This is a read-only control. + + + + +
+ +