diff --git a/ffmpeg.c b/ffmpeg.c
index 287b1c18e3..c4e3099780 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1161,7 +1161,7 @@ static void do_video_out(AVFormatContext *s,
     if (!ost->last_frame)
         ost->last_frame = av_frame_alloc();
     av_frame_unref(ost->last_frame);
-    if (next_picture)
+    if (next_picture && ost->last_frame)
         av_frame_ref(ost->last_frame, next_picture);
     else
         av_frame_free(&ost->last_frame);