Function mov_write_header

libavformat/movenc.c:8385–8563

}

static int mov_write_header(AVFormatContext *s)
{
    AVIOContext *pb = s->pb;
    MOVMuxContext *mov = s->priv_data;
    int ret, hint_track = 0, tmcd_track = 0, nb_tracks = mov->nb_streams;

    if (mov->mode & (MODE_MP4|MODE_MOV|MODE_IPOD) && s->nb_chapters)
        nb_tracks++;

    if (mov->flags & FF_MOV_FLAG_RTP_HINT) {
        hint_track = nb_tracks;
        for (int i = 0; i < mov->nb_streams; i++) {
            if (rtp_hinting_needed(mov->tracks[i].st))
                nb_tracks++;
        }
    }

    if (mov->nb_meta_tmcd)
        tmcd_track = nb_tracks;

    for (int i = 0; i < mov->nb_streams; i++) {
        MOVTrack *track = &mov->tracks[i];
        AVStream *st = track->st;

        /* copy extradata if it exists */
        if (st->codecpar->extradata_size) {
            if (st->codecpar->codec_id == AV_CODEC_ID_DVD_SUBTITLE)
                mov_create_dvd_sub_decoder_specific_info(track, st);
            else if (!TAG_IS_AVCI(track->tag) && st->codecpar->codec_id != AV_CODEC_ID_DNXHD) {
                track->extradata_size[track->last_stsd_index]  = st->codecpar->extradata_size;
                track->extradata[track->last_stsd_index] =
                    av_malloc(track->extradata_size[track->last_stsd_index] + AV_INPUT_BUFFER_PADDING_SIZE);
                if (!track->extradata[track->last_stsd_index]) {
                    return AVERROR(ENOMEM);
                }
                memcpy(track->extradata[track->last_stsd_index],
                       st->codecpar->extradata, track->extradata_size[track->last_stsd_index]);
                memset(track->extradata[track->last_stsd_index] + track->extradata_size[track->last_stsd_index],
                       0, AV_INPUT_BUFFER_PADDING_SIZE);
            }
        }

        if (st->codecpar->codec_type != AVMEDIA_TYPE_AUDIO ||
            av_channel_layout_compare(&track->par->ch_layout,
                                      &(AVChannelLayout)AV_CHANNEL_LAYOUT_MONO))
            continue;

        for (int j = 0; j < mov->nb_streams; j++) {
            AVStream *stj= mov->tracks[j].st;
            MOVTrack *trackj= &mov->tracks[j];
            if (j == i)
                continue;

            if (stj->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
                (trackj->par->ch_layout.nb_channels != 1 ||
                 !av_channel_layout_compare(&trackj->par->ch_layout,
                                            &(AVChannelLayout)AV_CHANNEL_LAYOUT_MONO))
            )