From 31fca59294d2a916c3c74fcd90310ec293480b02 Mon Sep 17 00:00:00 2001 From: Andreas Eversberg Date: Fri, 23 Aug 2019 11:31:11 +0200 Subject: Fixed performance issue with IIR filter Passing samples with zero value (0.0) causes very slow processing of IIR filter on my test machine 'nuedel'. I don't know why. To solve this, I add a very small number to each input sample. --- src/libfilter/iir_filter.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'src/libfilter') diff --git a/src/libfilter/iir_filter.c b/src/libfilter/iir_filter.c index 2123feb..5872d61 100644 --- a/src/libfilter/iir_filter.c +++ b/src/libfilter/iir_filter.c @@ -104,7 +104,7 @@ void iir_notch_init(iir_filter_t *filter, double frequency, int samplerate, int filter->b1 = filter->a1; filter->b2 = (1 - K / Q + K * K) * norm; } - + void iir_process(iir_filter_t *filter, sample_t *samples, int length) { double a0, a1, a2, b1, b2; @@ -126,7 +126,8 @@ void iir_process(iir_filter_t *filter, sample_t *samples, int length) /* process filter */ for (i = 0; i < length; i++) { - in = *samples; + /* add a small value, otherwise this loop will perform really bad on my 'nuedel' machine!!! */ + in = *samples + 0.000000001; for (j = 0; j < iterations; j++) { out = in * a0 + z1[j]; z1[j] = in * a1 + z2[j] - b1 * out; @@ -163,7 +164,8 @@ void iir_process_baseband(iir_filter_t *filter, float *baseband, int length) /* process filter */ for (i = 0; i < length; i++) { - in = *baseband; + /* add a small value, otherwise this loop will perform really bad on my 'nuedel' machine!!! */ + in = *baseband + 0.000000001; for (j = 0; j < iterations; j++) { out = in * a0 + z1[j]; #ifdef DEBUG_NAN -- cgit v1.2.3