[SCM] libav/experimental: remove dithering of filter coefficients, improves precision by 1-2 bits and improves subjective sound quality on artificial sample (udial.wav resampling to 32khz)
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:58:03 UTC 2013
The following commit has been merged in the experimental branch:
commit 66a148a19ae6c6284afeaf7a14dea6ba49069a9a
Author: Michael Niedermayer <michaelni at gmx.at>
Date: Wed Mar 21 22:02:52 2007 +0000
remove dithering of filter coefficients, improves precision by 1-2 bits and
improves subjective sound quality on artificial sample (udial.wav resampling
to 32khz)
Originally committed as revision 8467 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/libavcodec/resample2.c b/libavcodec/resample2.c
index 9cc2edb..82eddf6 100644
--- a/libavcodec/resample2.c
+++ b/libavcodec/resample2.c
@@ -93,7 +93,6 @@ void av_build_filter(FELEM *filter, double factor, int tap_count, int phase_coun
for(ph=0;ph<phase_count;ph++) {
double norm = 0;
- double e= 0;
for(i=0;i<tap_count;i++) {
x = M_PI * ((double)(i - center) - (double)ph / phase_count) * factor;
if (x == 0) y = 1.0;
@@ -121,9 +120,8 @@ void av_build_filter(FELEM *filter, double factor, int tap_count, int phase_coun
/* normalize so that an uniform color remains the same */
for(i=0;i<tap_count;i++) {
- v = av_clip(lrintf(tab[i] * scale / norm + e), FELEM_MIN, FELEM_MAX);
+ v = av_clip(lrintf(tab[i] * scale / norm), FELEM_MIN, FELEM_MAX);
filter[ph * tap_count + i] = v;
- e += tab[i] * scale / norm - v;
}
}
}
--
Libav/FFmpeg packaging
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