Function parse_chunk

libavformat/usmdec.c:230–367

}

static int64_t parse_chunk(AVFormatContext *s, AVIOContext *pb,
                           uint32_t chunk_type, uint32_t chunk_size,
                           AVPacket *pkt)
{
    const int is_audio = chunk_type == MKBETAG('@','S','F','A');
    const int is_alpha = chunk_type == MKBETAG('@','A','L','P');
    const int is_subtt = chunk_type == MKBETAG('@','S','B','T');
    USMDemuxContext *usm = s->priv_data;
    int padding_size, payload_type, payload_offset;
    const int ch_type = is_subtt ? SUBTTI : is_audio ? AUDIOI : is_alpha ? ALPHAI : VIDEOI;
    int stream_index, frame_rate;
    int64_t chunk_start, ret;

    ret = avio_tell(pb);
    if (ret < 0)
        return ret;
    chunk_start = ret;
    avio_skip(pb, 1);
    payload_offset = avio_r8(pb);
    padding_size = avio_rb16(pb);
    stream_index = avio_r8(pb);
    avio_skip(pb, 2);
    payload_type = avio_r8(pb);
    /*frame_time =*/ avio_rb32(pb);
    frame_rate = avio_rb32(pb);
    avio_skip(pb, 8);
    ret = avio_tell(pb);
    if (ret < 0)
        return ret;
    ret = avio_skip(pb, FFMAX(0, (ret - chunk_start) - payload_offset));
    if (ret < 0)
        return ret;

    if (payload_type == 1) {
        if (usm->ch[ch_type][stream_index].used == 0) {
            USMChannel *ch = &usm->ch[ch_type][stream_index];

            switch (ch_type) {
            case ALPHAI:
            case VIDEOI:
                ch->type = AVMEDIA_TYPE_VIDEO;
                break;
            case AUDIOI:
                ch->type = AVMEDIA_TYPE_AUDIO;
                break;
            case SUBTTI:
                ch->type = AVMEDIA_TYPE_SUBTITLE;
                break;
            default:
                return AVERROR_INVALIDDATA;
            }

            ch->used = 1;
            ch->index = -1;
            usm->nb_channels[ch_type]++;

            ret = parse_utf(s, pb, ch, ch_type, chunk_size);
            if (ret < 0)