diff --git a/libavcodec/h264idct_template.c b/libavcodec/h264idct_template.c
index f19579a47c..ce66ed3ab8 100644
--- a/libavcodec/h264idct_template.c
+++ b/libavcodec/h264idct_template.c
@@ -283,8 +283,8 @@ void FUNCC(ff_h264_chroma422_dc_dequant_idct)(int16_t *_block, int qmul){
     dctcoef *block = (dctcoef*)_block;
 
     for(i=0; i<4; i++){
-        temp[2*i+0] = block[stride*i + xStride*0] + block[stride*i + xStride*1];
-        temp[2*i+1] = block[stride*i + xStride*0] - block[stride*i + xStride*1];
+        temp[2*i+0] = block[stride*i + xStride*0] + (unsigned)block[stride*i + xStride*1];
+        temp[2*i+1] = block[stride*i + xStride*0] - (unsigned)block[stride*i + xStride*1];
     }
 
     for(i=0; i<2; i++){