static int xvag_read_header(AVFormatContext *s)

{

    unsigned offset, big_endian, codec;

    AVStream *st;



    avio_skip(s->pb, 4);



    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);



    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;



    offset     = avio_rl32(s->pb);

    big_endian = offset > av_bswap32(offset);

    if (big_endian) {

        offset                 = av_bswap32(offset);

        avio_skip(s->pb, 28);

        codec                  = avio_rb32(s->pb);

        st->codecpar->channels = avio_rb32(s->pb);

        avio_skip(s->pb, 4);

        st->duration           = avio_rb32(s->pb);

        avio_skip(s->pb, 8);

        st->codecpar->sample_rate = avio_rb32(s->pb);

    } else {

        avio_skip(s->pb, 28);

        codec                  = avio_rl32(s->pb);

        st->codecpar->channels = avio_rl32(s->pb);

        avio_skip(s->pb, 4);

        st->duration           = avio_rl32(s->pb);

        avio_skip(s->pb, 8);

        st->codecpar->sample_rate = avio_rl32(s->pb);

    }



    if (st->codecpar->sample_rate <= 0)

        return AVERROR_INVALIDDATA;

    if (st->codecpar->channels <= 0)

        return AVERROR_INVALIDDATA;



    switch (codec) {

    case 0x1c:

        st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_PSX;

        st->codecpar->block_align = 16 * st->codecpar->channels;

        break;

    default:

        avpriv_request_sample(s, "codec %X", codec);

        return AVERROR_PATCHWELCOME;

    };



    avio_skip(s->pb, offset - avio_tell(s->pb));



    if (avio_rb16(s->pb) == 0xFFFB) {

        st->codecpar->codec_id    = AV_CODEC_ID_MP3;

        st->codecpar->block_align = 0x1000;

        st->need_parsing       = AVSTREAM_PARSE_FULL_RAW;

    }



    avio_skip(s->pb, -2);

    avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);



    return 0;

}
