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Use the new VLC table for the first non trailing coeff too. 

Sadly only 5 cycles faster here on pentium dual. So maybe the
complexity is not worth it and this should be reverted ...

Originally committed as revision 16295 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2008-12-23 19:10:46 +00:00
parent 593af7cdda
commit d42fc4a8ca
1 changed files with 18 additions and 5 deletions
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23
libavcodec/h264.c
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@ -4142,9 +4142,16 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in
level[2] = 1-((i&1)<<1);
if(trailing_ones<total_coeff) {
int level_code, mask;
int mask, prefix;
int suffix_length = total_coeff > 10 && trailing_ones < 3;
int prefix= get_level_prefix(gb);
int bitsi= show_bits(gb, LEVEL_TAB_BITS);
int level_code= cavlc_level_tab[suffix_length][bitsi][0];
skip_bits(gb, cavlc_level_tab[suffix_length][bitsi][1]);
if(level_code >= 100){
prefix= level_code - 100;
if(prefix == LEVEL_TAB_BITS)
prefix += get_level_prefix(gb);
//first coefficient has suffix_length equal to 0 or 1
if(prefix<14){ //FIXME try to build a large unified VLC table for all this
@ -4166,11 +4173,17 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in
if(trailing_ones < 3) level_code += 2;
suffix_length = 1;
if(level_code > 5)
suffix_length++;
suffix_length = 2;
mask= -(level_code&1);
level[trailing_ones]= (((2+level_code)>>1) ^ mask) - mask;
}else{
if(trailing_ones < 3) level_code += (level_code>>31)|1;
suffix_length = 1;
if(level_code + 3U > 6U)
suffix_length++;
level[trailing_ones]= level_code;
}
//remaining coefficients have suffix_length > 0
for(i=trailing_ones+1;i<total_coeff;i++) {