diff --git a/libavcodec/smc.c b/libavcodec/smc.c
index 2bd3176f8e..257d5dae5f 100644
--- a/libavcodec/smc.c
+++ b/libavcodec/smc.c
@@ -69,7 +69,7 @@ typedef struct SmcContext {
         row_ptr += stride * 4; \
     } \
     total_blocks--; \
-    if (total_blocks < 0) \
+    if (total_blocks < !!n_blocks) \
     { \
         av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
         return; \