[FFmpeg-cvslog] libswresample: Avoid needlessly large on-stack array.
Reimar Döffinger
git at videolan.org
Sun Sep 7 11:32:41 CEST 2014
ffmpeg | branch: master | Reimar Döffinger <Reimar.Doeffinger at gmx.de> | Tue Sep 2 23:50:55 2014 +0200| [2231d5b67185674ddd1703abf92ea0020f63ca04] | committer: Reimar Döffinger
libswresample: Avoid needlessly large on-stack array.
We only actually need to use a tiny part of it.
Unfortunately we seem to have no real test coverage on
the code, so this is a bit risky.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2231d5b67185674ddd1703abf92ea0020f63ca04
---
libswresample/rematrix.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/libswresample/rematrix.c b/libswresample/rematrix.c
index bf2abcf..62662f8 100644
--- a/libswresample/rematrix.c
+++ b/libswresample/rematrix.c
@@ -56,6 +56,7 @@
#define TOP_BACK_LEFT 15
#define TOP_BACK_CENTER 16
#define TOP_BACK_RIGHT 17
+#define NUM_NAMED_CHANNELS 18
int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride)
{
@@ -112,7 +113,7 @@ static int sane_layout(int64_t layout){
av_cold static int auto_matrix(SwrContext *s)
{
int i, j, out_i;
- double matrix[64][64]={{0}};
+ double matrix[NUM_NAMED_CHANNELS][NUM_NAMED_CHANNELS]={{0}};
int64_t unaccounted, in_ch_layout, out_ch_layout;
double maxcoef=0;
char buf[128];
@@ -145,7 +146,7 @@ av_cold static int auto_matrix(SwrContext *s)
}
memset(s->matrix, 0, sizeof(s->matrix));
- for(i=0; i<64; i++){
+ for(i=0; i<FF_ARRAY_ELEMS(matrix); i++){
if(in_ch_layout & out_ch_layout & (1ULL<<i))
matrix[i][i]= 1.0;
}
@@ -299,9 +300,12 @@ av_cold static int auto_matrix(SwrContext *s)
double sum=0;
int in_i=0;
for(j=0; j<64; j++){
- s->matrix[out_i][in_i]= matrix[i][j];
- if(matrix[i][j]){
- sum += fabs(matrix[i][j]);
+ if (i < FF_ARRAY_ELEMS(matrix) && j < FF_ARRAY_ELEMS(matrix[0]))
+ s->matrix[out_i][in_i]= matrix[i][j];
+ else
+ s->matrix[out_i][in_i]= i == j && (in_ch_layout & out_ch_layout & (1ULL<<i));
+ if(s->matrix[out_i][in_i]){
+ sum += fabs(s->matrix[out_i][in_i]);
}
if(in_ch_layout & (1ULL<<j))
in_i++;
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