static int sox_read_header(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    unsigned header_size, comment_size;

    double sample_rate, sample_rate_frac;

    AVStream *st;



    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);



    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;



    if (avio_rl32(pb) == SOX_TAG) {

        st->codecpar->codec_id = AV_CODEC_ID_PCM_S32LE;

        header_size         = avio_rl32(pb);

        avio_skip(pb, 8); 

        sample_rate         = av_int2double(avio_rl64(pb));

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

        comment_size        = avio_rl32(pb);

    } else {

        st->codecpar->codec_id = AV_CODEC_ID_PCM_S32BE;

        header_size         = avio_rb32(pb);

        avio_skip(pb, 8); 

        sample_rate         = av_int2double(avio_rb64(pb));

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

        comment_size        = avio_rb32(pb);

    }



    if (comment_size > 0xFFFFFFFFU - SOX_FIXED_HDR - 4U) {

        av_log(s, AV_LOG_ERROR, "invalid comment size (%u)\n", comment_size);

        return AVERROR_INVALIDDATA;

    }



    if (sample_rate <= 0 || sample_rate > INT_MAX) {

        av_log(s, AV_LOG_ERROR, "invalid sample rate (%f)\n", sample_rate);

        return AVERROR_INVALIDDATA;

    }



    sample_rate_frac = sample_rate - floor(sample_rate);

    if (sample_rate_frac)

        av_log(s, AV_LOG_WARNING,

               "truncating fractional part of sample rate (%f)\n",

               sample_rate_frac);



    if ((header_size + 4) & 7 || header_size < SOX_FIXED_HDR + comment_size

        || st->codecpar->channels > 65535)  {

        av_log(s, AV_LOG_ERROR, "invalid header\n");

        return AVERROR_INVALIDDATA;

    }



    if (comment_size && comment_size < UINT_MAX) {

        char *comment = av_malloc(comment_size+1);

        if(!comment)

            return AVERROR(ENOMEM);

        if (avio_read(pb, comment, comment_size) != comment_size) {

            av_freep(&comment);

            return AVERROR(EIO);

        }

        comment[comment_size] = 0;



        av_dict_set(&s->metadata, "comment", comment,

                               AV_DICT_DONT_STRDUP_VAL);

    }



    avio_skip(pb, header_size - SOX_FIXED_HDR - comment_size);



    st->codecpar->sample_rate           = sample_rate;

    st->codecpar->bits_per_coded_sample = 32;

    st->codecpar->bit_rate              = st->codecpar->sample_rate *

                                          st->codecpar->bits_per_coded_sample *

                                          st->codecpar->channels;

    st->codecpar->block_align           = st->codecpar->bits_per_coded_sample *

                                          st->codecpar->channels / 8;



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



    return 0;

}
