tag = track->enc->codec_tag; if (!tag)
static int mov_write_video_tag(ByteIOContext *pb, MOVTrack* track){    int pos = url_ftell(pb);    int tag;    put_be32(pb, 0); /* size */    tag = codec_get_tag(codec_movvideo_tags, track->enc->codec_id);    // if no mac fcc found, try with Microsoft tags    if (!tag)	tag = codec_get_tag(codec_bmp_tags, track->enc->codec_id);    put_le32(pb, tag); // store it byteswapped    put_be32(pb, 0); /* Reserved */    put_be16(pb, 0); /* Reserved */    put_be16(pb, 1); /* Data-reference index */    put_be32(pb, 0); /* Reserved (= 02000c) */    put_be32(pb, 0); /* Reserved ("SVis")*/    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved (400)*/    put_be16(pb, track->enc->width); /* Video width */    put_be16(pb, track->enc->height); /* Video height */    put_be32(pb, 0x00480000); /* Reserved */    put_be32(pb, 0x00480000); /* Reserved */    put_be32(pb, 0); /* Data size (= 0) */    put_be16(pb, 1); /* Frame count (= 1) */        put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */    put_be32(pb, 0); /* Reserved */        put_be16(pb, 0x18); /* Reserved */    put_be16(pb, 0xffff); /* Reserved */    if(track->enc->codec_id == CODEC_ID_MPEG4)        mov_write_esds_tag(pb, track);    else if(track->enc->codec_id == CODEC_ID_H263)        mov_write_d263_tag(pb);    else if(track->enc->codec_id == CODEC_ID_SVQ3)        mov_write_svq3_tag(pb);        return updateSize (pb, pos);}