[FFmpeg-devel] [PATCH] libavfilter: improve atempo audio quality

[pkoshevoy at gmail.com]

From: Pavel Koshevoy <pkoshevoy at gmail.com>

Reduce audio fragment alignment jitter by penalizing alignment
correction offsets that deviate too much from the target offset.
This is accomplished by multiplying the cross correlation search
window with a quadratic function.

Signed-off-by: Pavel Koshevoy <pavel at homestead.aragog.com>
---
 libavfilter/af_atempo.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/libavfilter/af_atempo.c b/libavfilter/af_atempo.c
index 1ccc3f5..92390cf 100644
--- a/libavfilter/af_atempo.c
+++ b/libavfilter/af_atempo.c
@@ -654,7 +654,7 @@ static int yae_align(AudioFragment *frag,
 
         // normalize:
         FFTSample drifti = (FFTSample)(drift + i);
-        metric *= drifti;
+        metric *= drifti * (FFTSample)(i - i0) * (FFTSample)(i1 - i);
 
         if (metric > best_metric) {
             best_metric = metric;
-- 
1.7.7