diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index 160528e007..56aecd514e 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -109,7 +109,7 @@ static int decode_plane(UtvideoContext *c, int plane_no,
                 for (i = 0; i < width * step; i += step) {
                     pix = fsym;
                     if (use_pred) {
-                        prev += pix;
+                        prev += (unsigned)pix;
                         pix   = prev;
                     }
                     dest[i] = pix;