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lavfi/mp/mcdeint: avoid uninited data read

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Do not read padding or out-of-buffer values when computing the output
value for a pixel close to the image buffer edge.

This avoids non visible artifacts which affected the output checksum.

See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi/mp/mcdeint: avoid uninited data read
Date: Thu, 30 May 2013 18:57:14 +0200
This commit is contained in:
Stefano Sabatini 2013-05-31 00:36:50 +02:00
parent 534f1a2821
commit 3a2b9911bf
1 changed files with 32 additions and 10 deletions
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42
libavfilter/libmpcodecs/vf_mcdeint.c
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@ -115,27 +115,49 @@ static void filter(struct vf_priv_s *p, uint8_t *dst[3], uint8_t *src[3], int ds
for(y=0; y<h; y++){
if((y ^ p->parity) & 1){
for(x=0; x<w; x++){
if((x-2)+(y-1)*w>=0 && (x+2)+(y+1)*w<w*h){ //FIXME either alloc larger images or optimize this
if(y>0 && y<h-1){
int is_edge= x<3 || x>w-4;
uint8_t *filp= &p->frame_dec->data[i][x + y*fils];
uint8_t *srcp= &src[i][x + y*srcs];
int diff0= filp[-fils] - srcp[-srcs];
int diff1= filp[+fils] - srcp[+srcs];
int spatial_score= ABS(srcp[-srcs-1] - srcp[+srcs-1])
+ABS(srcp[-srcs ] - srcp[+srcs ])
+ABS(srcp[-srcs+1] - srcp[+srcs+1]) - 1;
int temp= filp[0];
#define DELTA(j) av_clip(j, -x, w-1-x)
#define GET_SCORE_EDGE(j)\
ABS(srcp[-srcs+DELTA(-1+(j))] - srcp[+srcs+DELTA(-1-(j))])+\
ABS(srcp[-srcs+DELTA(j) ] - srcp[+srcs+DELTA( -(j))])+\
ABS(srcp[-srcs+DELTA(1+(j)) ] - srcp[+srcs+DELTA( 1-(j))])
#define GET_SCORE(j)\
ABS(srcp[-srcs-1+(j)] - srcp[+srcs-1-(j)])+\
ABS(srcp[-srcs +(j)] - srcp[+srcs -(j)])+\
ABS(srcp[-srcs+1+(j)] - srcp[+srcs+1-(j)])
#define CHECK_EDGE(j)\
{ int score= GET_SCORE_EDGE(j);\
if(score < spatial_score){\
spatial_score= score;\
diff0= filp[-fils+DELTA(j)] - srcp[-srcs+DELTA(j)];\
diff1= filp[+fils+DELTA(-(j))] - srcp[+srcs+DELTA(-(j))];\
#define CHECK(j)\
{ int score= ABS(srcp[-srcs-1+(j)] - srcp[+srcs-1-(j)])\
+ ABS(srcp[-srcs +(j)] - srcp[+srcs -(j)])\
+ ABS(srcp[-srcs+1+(j)] - srcp[+srcs+1-(j)]);\
{ int score= GET_SCORE(j);\
if(score < spatial_score){\
spatial_score= score;\
diff0= filp[-fils+(j)] - srcp[-srcs+(j)];\
diff1= filp[+fils-(j)] - srcp[+srcs-(j)];
diff1= filp[+fils-(j)] - srcp[+srcs-(j)];\
CHECK(-1) CHECK(-2) }} }}
CHECK( 1) CHECK( 2) }} }}
if (is_edge) {
int spatial_score= GET_SCORE_EDGE(0)-1;
CHECK_EDGE(-1) CHECK_EDGE(-2) }} }}
CHECK_EDGE( 1) CHECK_EDGE( 2) }} }}
} else {
int spatial_score= GET_SCORE(0)-1;
CHECK(-1) CHECK(-2) }} }}
CHECK( 1) CHECK( 2) }} }}
}
#if 0
if((diff0 ^ diff1) > 0){
int mindiff= ABS(diff0) > ABS(diff1) ? diff1 : diff0;