diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 8e704a6af2..7f9d2078a1 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -726,7 +726,7 @@ typedef struct MpegEncContext {
 
 #define REBASE_PICTURE(pic, new_ctx, old_ctx) (pic ? \
     (pic >= old_ctx->picture && pic < old_ctx->picture+old_ctx->picture_count ?\
-        &new_ctx->picture[pic - old_ctx->picture] : pic - (Picture*)old_ctx + (Picture*)new_ctx)\
+        &new_ctx->picture[pic - old_ctx->picture] : (Picture*) ((uint8_t*)pic - (uint8_t*)old_ctx + (uint8_t*)new_ctx))\
     : NULL)
 
 /* mpegvideo_enc common options */