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Code Issues Releases Activity

mv overflow in map fix (untested except regression tests)

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Originally committed as revision 7287 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-12-12 13:31:12 +00:00
parent 428cc588f2
commit 2b0cdd9ec6
1 changed files with 10 additions and 3 deletions
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13
libavcodec/motion_est_template.c
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@ -823,20 +823,27 @@ static int sab_diamond_search(MpegEncContext * s, int *best, int dmin,
cmpf= s->dsp.me_cmp[size];
chroma_cmpf= s->dsp.me_cmp[size+1];
for(j=i=0; i<ME_MAP_SIZE; i++){
/*Note j<MAX_SAB_SIZE is needed if MAX_SAB_SIZE < ME_MAP_SIZE as j can
become larger due to MVs overflowing their ME_MAP_MV_BITS bits space in map
*/
for(j=i=0; i<ME_MAP_SIZE && j<MAX_SAB_SIZE; i++){
uint32_t key= map[i];
key += (1<<(ME_MAP_MV_BITS-1)) + (1<<(2*ME_MAP_MV_BITS-1));
if((key&((-1)<<(2*ME_MAP_MV_BITS))) != map_generation) continue;
assert(j<MAX_SAB_SIZE); //max j = number of predictors
minima[j].height= score_map[i];
minima[j].x= key & ((1<<ME_MAP_MV_BITS)-1); key>>=ME_MAP_MV_BITS;
minima[j].y= key & ((1<<ME_MAP_MV_BITS)-1);
minima[j].x-= (1<<(ME_MAP_MV_BITS-1));
minima[j].y-= (1<<(ME_MAP_MV_BITS-1));
// all entries in map should be in range except if the mv overflows their ME_MAP_MV_BITS bits space
if( minima[j].x > xmax || minima[j].x < xmin
|| minima[j].y > ymax || minima[j].y < ymin)
continue;
minima[j].checked=0;
if(minima[j].x || minima[j].y)
minima[j].height+= (mv_penalty[((minima[j].x)<<shift)-pred_x] + mv_penalty[((minima[j].y)<<shift)-pred_y])*penalty_factor;