avformat/movenc: make AVStream easier to access

This adds a AVStream pointer to Track
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/movenc.c

@@ -3738,6 +3738,7 @@ static int mov_write_header(AVFormatContext *s)
         AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,0);
 
         track->enc = st->codec;
+        track->st = st;
         track->language = ff_mov_iso639_to_lang(lang?lang->value:"und", mov->mode!=MODE_MOV);
         if (track->language < 0)
             track->language = 0;

libavformat/movenc.h

@@ -98,6 +98,7 @@ typedef struct MOVTrack {
     int         language;
     int         track_id;
     int         tag; ///< stsd fourcc
+    AVStream    *st;
     AVCodecContext *enc;
 
     int         vos_len;