static int msf_read_header(AVFormatContext *s)

{

    unsigned codec, align, size;

    AVStream *st;



    avio_skip(s->pb, 4);



    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);



    st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;

    codec                  = avio_rb32(s->pb);

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

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

        return AVERROR_INVALIDDATA;

    size = avio_rb32(s->pb);

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

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

        return AVERROR_INVALIDDATA;

    align = avio_rb32(s->pb) ;

    if (align > INT_MAX / st->codec->channels)

        return AVERROR_INVALIDDATA;

    st->codec->block_align = align;

    switch (codec) {

    case 0: st->codec->codec_id = AV_CODEC_ID_PCM_S16BE; break;

    case 3: st->codec->block_align = 16 * st->codec->channels;

            st->codec->codec_id = AV_CODEC_ID_ADPCM_PSX; break;

    case 7: st->need_parsing = AVSTREAM_PARSE_FULL_RAW;

            st->codec->codec_id = AV_CODEC_ID_MP3;       break;

    default:

            avpriv_request_sample(s, "Codec %d", codec);

            return AVERROR_PATCHWELCOME;

    }

    st->duration = av_get_audio_frame_duration(st->codec, size);

    avio_skip(s->pb, 0x40 - avio_tell(s->pb));

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



    return 0;

}
