diff --git a/libavcodec/dcadsp.c b/libavcodec/dcadsp.c
index fade1a6c02..f97874fbe6 100644
--- a/libavcodec/dcadsp.c
+++ b/libavcodec/dcadsp.c
@@ -328,7 +328,7 @@ static void dmix_add_c(int32_t *dst, const int32_t *src, int coeff, ptrdiff_t le
     int i;
 
     for (i = 0; i < len; i++)
-        dst[i] += mul15(src[i], coeff);
+        dst[i] += (unsigned)mul15(src[i], coeff);
 }
 
 static void dmix_scale_c(int32_t *dst, int scale, ptrdiff_t len)