diff --git a/libavcodec/h264_mp4toannexb_bsf.c b/libavcodec/h264_mp4toannexb_bsf.c
index 3ec4170e42..be42304c77 100644
--- a/libavcodec/h264_mp4toannexb_bsf.c
+++ b/libavcodec/h264_mp4toannexb_bsf.c
@@ -117,7 +117,7 @@ pps:
     }
 
     if (out)
-        memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+        memset(out + total_size, 0, padding);
 
     if (!sps_seen)
         av_log(avctx, AV_LOG_WARNING,