swscale: fix 16-bit horizontal scaling underflow.

When using e.g. lanczos scaling, values can drop below 0, so they
should never be unsigned.

1 files changed, 1 insertions, 1 deletions

diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 14807fdc46..a302373b85 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -1854,7 +1854,7 @@ static void hScale16_c(SwsContext *c, int16_t *_dst, int dstW, const uint8_t *_s
     for (i = 0; i < dstW; i++) {
         int j;
         int srcPos = filterPos[i];
-        unsigned int val = 0;
+        int val = 0;
 
         for (j = 0; j < filterSize; j++) {
             val += src[srcPos + j] * filter[filterSize * i + j];