diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 31edb9399e..a1c1a44f04 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -6880,6 +6880,7 @@ static int mov_write_trailer(AVFormatContext *s)
             AVCodecParameters *par = track->par;
 
             track->vos_len  = par->extradata_size;
+            av_freep(&track->vos_data);
             track->vos_data = av_malloc(track->vos_len + AV_INPUT_BUFFER_PADDING_SIZE);
             if (!track->vos_data)
                 return AVERROR(ENOMEM);