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optimizing high freq decode

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Originally committed as revision 6060 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-08-24 01:01:39 +00:00
parent daf4cd9ac3
commit 3c693e7743
1 changed files with 14 additions and 14 deletions
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28
libavcodec/mpegaudiodec.c
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@ -1741,22 +1741,22 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
}
last_gb= s->gb;
code = get_vlc2(&s->gb, vlc->table, vlc->bits, 2);
code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);
dprintf("t=%d code=%d\n", g->count1table_select, code);
if (code < 0)
return -1;
for(i=0;i<4;i++) {
if (code & (8 >> i)) {
/* non zero value. Could use a hand coded function for
'one' value */
v = l3_unscale(1, exponents[s_index]);
if(get_bits1(&s->gb))
v = -v;
} else {
v = 0;
}
g->sb_hybrid[s_index++] = v;
g->sb_hybrid[s_index+0]=
g->sb_hybrid[s_index+1]=
g->sb_hybrid[s_index+2]=
g->sb_hybrid[s_index+3]= 0;
while(code){
const static int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};
int pos= s_index+idxtab[code];
code ^= 8>>idxtab[code];
v = l3_unscale(1, exponents[pos]);
if(get_bits1(&s->gb))
v = -v;
g->sb_hybrid[pos] = v;
}
s_index+=4;
}
memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));
return 0;