dca: factorize scaling in inverse ADPCM
authorJanne Grunau <janne-libav@jannau.net>
Fri, 21 Feb 2014 12:13:36 +0000 (13:13 +0100)
committerJanne Grunau <janne-libav@jannau.net>
Fri, 28 Feb 2014 12:00:48 +0000 (13:00 +0100)
commit7686afd049be98d18663682b92d983340fa2c305
treee50dd1c93c3eef3bdb920b223bfcbb900816c915
parent08e3ea60ff4059341b74be04a428a38f7c3630b0
dca: factorize scaling in inverse ADPCM

Based on a patch from Christophe Gisquet.

Unrolling of the m == 0 case avoids a possible use of the uninitilized
value sum when s->predictor_history is not set. I failed to find a
sample for it. It also reduced the cycle count from 220 to 150 on
sandy bridge, x86_64 linux, gcc 4.8.2 compared to his patch.
libavcodec/dcadec.c