For small video dimensions, these calculations of the upper bound
for pixel access may have a negative result. Using an unsigned
comparison to bound a potentially negative value only works if
the greater operand is non-negative. Fixed by doing edge emulation
when the upper bound is probably negative, everywhere that this
pattern appears.
---
libavcodec/snow.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/libavcodec/snow.c b/libavcodec/snow.c
index 905e02a..ffbc6b9 100644
--- a/libavcodec/snow.c
+++ b/libavcodec/snow.c
@@ -337,8 +337,9 @@ void ff_snow_pred_block(SnowContext *s, uint8_t *dst,
uint8_t *tmp, int stride,
sx += (mx>>4) - (HTAPS_MAX/2-1);
sy += (my>>4) - (HTAPS_MAX/2-1);
src += sx + sy*stride;
- if( (unsigned)sx >= w - b_w - (HTAPS_MAX-2)
- || (unsigned)sy >= h - b_h - (HTAPS_MAX-2)){
+ if(w - b_w < HTAPS_MAX - 2 || h - b_h < HTAPS_MAX - 2 ||
+ (unsigned)sx >= w - b_w - (HTAPS_MAX-2) ||
+ (unsigned)sy >= h - b_h - (HTAPS_MAX-2)) {
s->dsp.emulated_edge_mc(tmp + MB_SIZE, src, stride,
b_w+HTAPS_MAX-1, b_h+HTAPS_MAX-1, sx, sy, w, h);
src= tmp + MB_SIZE;
}
--
1.7.5.4
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