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prefetch pixels for future motion compensation. 4-10% faster mpeg1/2/4 decoding (on an athlon-xp).

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Originally committed as revision 5204 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Loren Merritt 2006-03-23 21:54:46 +00:00
parent 513fbd8e5a
commit e77ef2755a
1 changed files with 14 additions and 0 deletions
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14
libavcodec/mpegvideo.c
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@ -3359,6 +3359,18 @@ static inline void chroma_4mv_motion_lowres(MpegEncContext *s,
pix_op[lowres](dest_cr, ptr, s->uvlinesize, block_s, sx, sy);
}
static inline void prefetch_motion(MpegEncContext *s, uint8_t **pix, int dir){
/* fetch pixels for estimated mv 4 macroblocks ahead
* optimized for 64byte cache lines */
const int shift = s->quarter_sample ? 2 : 1;
const int mx= (s->mv[dir][0][0]>>shift) + 16*s->mb_x + 8;
const int my= (s->mv[dir][0][1]>>shift) + 16*s->mb_y;
int off= mx + (my + (s->mb_x&3)*4)*s->linesize + 64;
s->dsp.prefetch(pix[0]+off, s->linesize, 4);
off= (mx>>1) + ((my>>1) + (s->mb_x&7))*s->uvlinesize + 64;
s->dsp.prefetch(pix[1]+off, pix[2]-pix[1], 2);
}
/**
* motion compensation of a single macroblock
* @param s context
@ -3383,6 +3395,8 @@ static inline void MPV_motion(MpegEncContext *s,
mb_x = s->mb_x;
mb_y = s->mb_y;
prefetch_motion(s, ref_picture, dir);
if(s->obmc && s->pict_type != B_TYPE){
int16_t mv_cache[4][4][2];
const int xy= s->mb_x + s->mb_y*s->mb_stride;