diff --git a/libavcodec/snowenc.c b/libavcodec/snowenc.c
index 49e8227e23..48929cf351 100644
--- a/libavcodec/snowenc.c
+++ b/libavcodec/snowenc.c
@@ -564,6 +564,9 @@ static int get_dc(SnowContext *s, int mb_x, int mb_y, int plane_index){
     }
     *b= backup;
 
+    if (!aa)
+        return 0;
+
     return av_clip_uint8( ROUNDED_DIV(ab<<LOG2_OBMC_MAX, aa) ); //FIXME we should not need clipping
 }