Merge commit '3559fb97'

* commit '3559fb97':
  movenc: Check that tracks->enc exists before trying to free extradata

Conflicts:
	libavformat/movenc.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/movenc.c

@@ -4044,7 +4044,8 @@ static int mov_write_trailer(AVFormatContext *s)
     }
 
     if (mov->chapter_track) {
-        av_freep(&mov->tracks[mov->chapter_track].enc->extradata);
+        if (mov->tracks[mov->chapter_track].enc)
+            av_freep(&mov->tracks[mov->chapter_track].enc->extradata);
         av_freep(&mov->tracks[mov->chapter_track].enc);
     }