[FFmpeg-devel] [PATCH 3/3] aacenc: Remove energy 'normalization' modification from the 3GPP psymodel

Nathan Caldwell saintdev
Tue Oct 26 01:30:32 CEST 2010


This greatly improves bitrate handling. You will now get within a few
kbps of your requested bitrate instead of 20-40kbps higher.

There is absolutely no analog to this line in the 3GPP spec, that I
can find.
---
 libavcodec/aacpsy.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 16528d6..7259d4c 100644
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -404,7 +404,6 @@ static void psy_3gpp_analyze(FFPsyContext *ctx, int channel,
             band->energy = 0.0f;
             for (i = 0; i < band_sizes[g]; i++)
                 band->energy += coefs[start+i] * coefs[start+i];
-            band->energy *= 1.0f / (512*512);
             band->thr     = band->energy * 0.001258925f;
             start        += band_sizes[g];

-- 
1.7.3.2



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