size += mov_write_tkhd_tag(pb, track); size += mov_write_mdia_tag(pb, track); writeSize (pb, pos, size); return size;
mov_write_tkhd_tag(pb, track); mov_write_mdia_tag(pb, track); return updateSize(pb, pos);
int mov_write_trak_tag(ByteIOContext *pb, MOVTrack* track){    int size = 8;    int pos;    pos = url_ftell(pb);    put_be32(pb, 0); /* size */    put_tag(pb, "trak");    size += mov_write_tkhd_tag(pb, track);    size += mov_write_mdia_tag(pb, track);    writeSize (pb, pos, size);    return size;}