From 303bd95cd2a8c2df5f0726dd2e435bb31d44aced Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 22 Mar 2007 11:10:30 +0000 Subject: [PATCH] optimize linear filter coeff interpolation code, this also makes the code less prone to overflows Originally committed as revision 8480 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/resample2.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/libavcodec/resample2.c b/libavcodec/resample2.c index e88e709..0cbe9b7 100644 --- a/libavcodec/resample2.c +++ b/libavcodec/resample2.c @@ -268,13 +268,12 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int }else if(sample_index + c->filter_length > src_size){ break; }else if(c->linear){ - int64_t v=0; - int sub_phase= (frac<<8) / c->src_incr; + FELEM2 v2=0; for(i=0; ifilter_length; i++){ - FELEML coeff= filter[i]*(256 - sub_phase) + filter[i + c->filter_length]*sub_phase; - v += src[sample_index + i] * coeff; + val += src[sample_index + i] * (FELEM2)filter[i]; + v2 += src[sample_index + i] * (FELEM2)filter[i + c->filter_length]; } - val= v>>8; + val+=(v2-val)*(FELEML)frac / c->src_incr; }else{ for(i=0; ifilter_length; i++){ val += src[sample_index + i] * (FELEM2)filter[i]; -- 2.7.4