wrapper/FFmpeg
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

10l: reverse the biquad coefficients.

Browse source 
I did not notice that the filter implementation uses a reversed history state.

Signed-off-by: Janne Grunau <janne-ffmpeg@jannau.net>
(cherry picked from commit 98cfadd648)
This commit is contained in:
Justin Ruggles 2011-01-21 20:59:20 +00:00 • committed by Michael Niedermayer
parent ba0dd9e8ff
commit ff5eded449
1 changed files with 6 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

12
libavcodec/iirfilter.c
View file

@ -137,15 +137,15 @@ static int biquad_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
if (filt_mode == FF_FILTER_MODE_HIGHPASS) {
c->gain = ((1.0 + cos_w0) / 2.0) / a0;
x0 = (-(1.0 + cos_w0)) / a0;
x1 = ((1.0 + cos_w0) / 2.0) / a0;
x0 = ((1.0 + cos_w0) / 2.0) / a0;
x1 = (-(1.0 + cos_w0)) / a0;
} else { // FF_FILTER_MODE_LOWPASS
c->gain = ((1.0 - cos_w0) / 2.0) / a0;
x0 = (1.0 - cos_w0) / a0;
x1 = ((1.0 - cos_w0) / 2.0) / a0;
x0 = ((1.0 - cos_w0) / 2.0) / a0;
x1 = (1.0 - cos_w0) / a0;
}
c->cy[0] = (2.0 * cos_w0) / a0;
c->cy[1] = (-1.0 + (sin_w0 / 2.0)) / a0;
c->cy[0] = (-1.0 + (sin_w0 / 2.0)) / a0;
c->cy[1] = (2.0 * cos_w0) / a0;
// divide by gain to make the x coeffs integers.
// during filtering, the delay state will include the gain multiplication