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Optimize decode_cabac_field_decoding_flag().

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~4 cpu cycles faster

Originally committed as revision 21447 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2010-01-25 02:44:34 +00:00
parent 7f8c3d1f4d
commit 2773920698
1 changed files with 6 additions and 12 deletions
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18
libavcodec/h264_cabac.c
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@ -706,21 +706,15 @@ void ff_h264_init_cabac_states(H264Context *h) {
static int decode_cabac_field_decoding_flag(H264Context *h) {
MpegEncContext * const s = &h->s;
const int mb_x = s->mb_x;
const int mb_y = s->mb_y & ~1;
const int mba_xy = mb_x - 1 + mb_y *s->mb_stride;
const int mbb_xy = mb_x + (mb_y-2)*s->mb_stride;
const long mba_xy = h->mb_xy - 1L;
const long mbb_xy = h->mb_xy - 2L*s->mb_stride;
unsigned int ctx = 0;
unsigned long ctx = 0;
if( h->slice_table[mba_xy] == h->slice_num && IS_INTERLACED( s->current_picture.mb_type[mba_xy] ) ) {
ctx += 1;
}
if( h->slice_table[mbb_xy] == h->slice_num && IS_INTERLACED( s->current_picture.mb_type[mbb_xy] ) ) {
ctx += 1;
}
ctx += (s->current_picture.mb_type[mba_xy]>>7)&(h->slice_table[mba_xy] == h->slice_num);
ctx += (s->current_picture.mb_type[mbb_xy]>>7)&(h->slice_table[mbb_xy] == h->slice_num);
return get_cabac_noinline( &h->cabac, &h->cabac_state[70 + ctx] );
return get_cabac_noinline( &h->cabac, &(h->cabac_state+70)[ctx] );
}
static int decode_cabac_intra_mb_type(H264Context *h, int ctx_base, int intra_slice) {