aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/DocBook/media/v4l/vidioc-enumstd.xml
blob: 3a5fc5405f96a869f0ff93262211c430dcbd4123 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
<refentry id="vidioc-enumstd">
  <refmeta>
    <refentrytitle>ioctl VIDIOC_ENUMSTD</refentrytitle>
    &manvol;
  </refmeta>

  <refnamediv>
    <refname>VIDIOC_ENUMSTD</refname>
    <refpurpose>Enumerate supported video standards</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcprototype>
	<funcdef>int <function>ioctl</function></funcdef>
	<paramdef>int <parameter>fd</parameter></paramdef>
	<paramdef>int <parameter>request</parameter></paramdef>
	<paramdef>struct v4l2_standard *<parameter>argp</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Arguments</title>

    <variablelist>
      <varlistentry>
	<term><parameter>fd</parameter></term>
	<listitem>
	  <para>&fd;</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><parameter>request</parameter></term>
	<listitem>
	  <para>VIDIOC_ENUMSTD</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><parameter>argp</parameter></term>
	<listitem>
	  <para></para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Description</title>

    <para>To query the attributes of a video standard,
especially a custom (driver defined) one, applications initialize the
<structfield>index</structfield> field of &v4l2-standard; and call the
<constant>VIDIOC_ENUMSTD</constant> 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 <errorcode>EINVAL</errorcode>. Drivers may enumerate a
different set of standards after switching the video input or
output.<footnote>
	<para>The supported standards may overlap and we need an
unambiguous set to find the current standard returned by
<constant>VIDIOC_G_STD</constant>.</para>
      </footnote></para>

    <table pgwide="1" frame="none" id="v4l2-standard">
      <title>struct <structname>v4l2_standard</structname></title>
      <tgroup cols="3">
	&cs-str;
	<tbody valign="top">
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>index</structfield></entry>
	    <entry>Number of the video standard, set by the
application.</entry>
	  </row>
	  <row>
	    <entry>&v4l2-std-id;</entry>
	    <entry><structfield>id</structfield></entry>
	    <entry>The bits in this field identify the standard as
one of the common standards listed in <xref linkend="v4l2-std-id" />,
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
<structfield>id</structfield> must be unique. No other enumerated
<structname>v4l2_standard</structname> structure, for this input or
output anyway, can contain the same set of bits.</entry>
	  </row>
	  <row>
	    <entry>__u8</entry>
	    <entry><structfield>name</structfield>[24]</entry>
	    <entry>Name of the standard, a NUL-terminated ASCII
string, for example: "PAL-B/G", "NTSC Japan". This information is
intended for the user.</entry>
	  </row>
	  <row>
	    <entry>&v4l2-fract;</entry>
	    <entry><structfield>frameperiod</structfield></entry>
	    <entry>The frame period (not field period) is numerator
/ denominator. For example M/NTSC has a frame period of 1001 /
30000 seconds.</entry>
	  </row>
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>framelines</structfield></entry>
	    <entry>Total lines per frame including blanking,
e.&nbsp;g. 625 for B/PAL.</entry>
	  </row>
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>reserved</structfield>[4]</entry>
	    <entry>Reserved for future extensions. Drivers must set
the array to zero.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <table pgwide="1" frame="none" id="v4l2-fract">
      <title>struct <structname>v4l2_fract</structname></title>
      <tgroup cols="3">
	&cs-str;
	<tbody valign="top">
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>numerator</structfield></entry>
	    <entry></entry>
	  </row>
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>denominator</structfield></entry>
	    <entry></entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <table pgwide="1" frame="none" id="v4l2-std-id">
      <title>typedef <structname>v4l2_std_id</structname></title>
      <tgroup cols="3">
	&cs-str;
	<tbody valign="top">
	  <row>
	    <entry>__u64</entry>
	    <entry><structfield>v4l2_std_id</structfield></entry>
	    <entry>This type is a set, each bit representing another
video standard as listed below and in <xref
linkend="video-standards" />. The 32 most significant bits are reserved
for custom (driver defined) video standards.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <para><programlisting>
#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)
</programlisting></para><para><constant>V4L2_STD_PAL_60</constant> 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.</para><para><programlisting>
#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)
</programlisting></para><para><constant>V4L2_STD_NTSC_443</constant>
is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC
color modulation with a 4.43 MHz color
subcarrier.</para><para><programlisting>
#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)
</programlisting></para><para><!-- ATSC proposal by Mark McClelland,
video4linux-list@redhat.com on 17 Oct 2002
--><constant>V4L2_STD_ATSC_8_VSB</constant> and
<constant>V4L2_STD_ATSC_16_VSB</constant> are U.S. terrestrial digital
TV standards. Presently the V4L2 API does not support digital TV. See
also the Linux DVB API at <ulink
url="http://linuxtv.org">http://linuxtv.org</ulink>.</para>
<para><programlisting>
#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)
</programlisting></para>

    <table pgwide="1" id="video-standards" orient="land">
      <title>Video Standards (based on [<xref linkend="itu470" />])</title>
      <tgroup cols="12" colsep="1" rowsep="1" align="center">
	<colspec colname="c1" align="left" />
	<colspec colname="c2" />
	<colspec colname="c3" />
	<colspec colname="c4" />
	<colspec colname="c5" />
	<colspec colnum="7" colname="c7" />
	<colspec colnum="9" colname="c9" />
	<colspec colnum="12" colname="c12" />
	<spanspec namest="c2" nameend="c3" spanname="m" align="center" />
	<spanspec namest="c4" nameend="c12" spanname="x" align="center" />
	<spanspec namest="c5" nameend="c7" spanname="b" align="center" />
	<spanspec namest="c9" nameend="c12" spanname="s" align="center" />
	<thead>
	  <row>
	    <entry>Characteristics</entry>
	    <entry><para>M/NTSC<footnote><para>Japan uses a standard
similar to M/NTSC
(V4L2_STD_NTSC_M_JP).</para></footnote></para></entry>
	    <entry>M/PAL</entry>
	    <entry><para>N/PAL<footnote><para> The values in
brackets apply to the combination N/PAL a.k.a.
N<subscript>C</subscript> used in Argentina
(V4L2_STD_PAL_Nc).</para></footnote></para></entry>
	    <entry align="center">B, B1, G/PAL</entry>
	    <entry align="center">D, D1, K/PAL</entry>
	    <entry align="center">H/PAL</entry>
	    <entry align="center">I/PAL</entry>
	    <entry align="center">B, G/SECAM</entry>
	    <entry align="center">D, K/SECAM</entry>
	    <entry align="center">K1/SECAM</entry>
	    <entry align="center">L/SECAM</entry>
	  </row>
	</thead>
	<tbody valign="top">
	  <row>
	    <entry>Frame lines</entry>
	    <entry spanname="m">525</entry>
	    <entry spanname="x">625</entry>
	  </row>
	  <row>
	    <entry>Frame period (s)</entry>
	    <entry spanname="m">1001/30000</entry>
	    <entry spanname="x">1/25</entry>
	  </row>
	  <row>
	    <entry>Chrominance sub-carrier frequency (Hz)</entry>
	    <entry>3579545 &plusmn;&nbsp;10</entry>
	    <entry>3579611.49 &plusmn;&nbsp;10</entry>
	    <entry>4433618.75 &plusmn;&nbsp;5 (3582056.25
&plusmn;&nbsp;5)</entry>
	    <entry spanname="b">4433618.75 &plusmn;&nbsp;5</entry>
	    <entry>4433618.75 &plusmn;&nbsp;1</entry>
	    <entry spanname="s">f<subscript>OR</subscript>&nbsp;=
4406250 &plusmn;&nbsp;2000, f<subscript>OB</subscript>&nbsp;= 4250000
&plusmn;&nbsp;2000</entry>
	  </row>
	  <row>
	    <entry>Nominal radio-frequency channel bandwidth
(MHz)</entry>
	    <entry>6</entry>
	    <entry>6</entry>
	    <entry>6</entry>
	    <entry>B: 7; B1, G: 8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	    <entry>8</entry>
	  </row>
	  <row>
	    <entry>Sound carrier relative to vision carrier
(MHz)</entry>
	    <entry>+&nbsp;4.5</entry>
	    <entry>+&nbsp;4.5</entry>
	    <entry>+&nbsp;4.5</entry>
	    <entry><para>+&nbsp;5.5 &plusmn;&nbsp;0.001
<footnote><para>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&nbsp;kHz above the frequency of the first sound carrier. For
stereophonic sound transmissions a similar system is used in
Australia.</para></footnote> <footnote><para>New Zealand uses a sound
carrier displaced 5.4996 &plusmn;&nbsp;0.0005 MHz from the vision
carrier.</para></footnote> <footnote><para>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&nbsp;MHz above the vision carrier and is DQPSK
modulated with 728&nbsp;kbit/s sound and data multiplex. (NICAM
system)</para></footnote> <footnote><para>In the United Kingdom, a
system of two sound carriers is used. The second sound carrier is
6.552&nbsp;MHz above the vision carrier and is DQPSK modulated with a
728&nbsp;kbit/s sound and data multiplex able to carry two sound
channels. (NICAM system)</para></footnote></para></entry>
	    <entry>+&nbsp;6.5 &plusmn;&nbsp;0.001</entry>
	    <entry>+&nbsp;5.5</entry>
	    <entry>+&nbsp;5.9996 &plusmn;&nbsp;0.0005</entry>
	    <entry>+&nbsp;5.5 &plusmn;&nbsp;0.001</entry>
	    <entry>+&nbsp;6.5 &plusmn;&nbsp;0.001</entry>
	    <entry>+&nbsp;6.5</entry>
	    <entry><para>+&nbsp;6.5 <footnote><para>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)</para></footnote></para></entry>
	  </row>
	</tbody>
      </tgroup>
    </table>
  </refsect1>

  <refsect1>
    &return-value;

    <variablelist>
      <varlistentry>
	<term><errorcode>EINVAL</errorcode></term>
	<listitem>
	  <para>The &v4l2-standard; <structfield>index</structfield>
is out of bounds.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
</refentry>