PeerStreamer

/*

 * MD STUDIO audio demuxer

 *

 * Copyright (c) 2009 Benjamin Larsson

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "avformat.h"

#include "pcm.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/audioconvert.h"

#define AT1_SU_SIZE     212

static int aea_read_probe(AVProbeData *p)

{

    if (p->buf_size <= 2048+212)

        return 0;

    /* Magic is '00 08 00 00' in Little Endian*/

    if (AV_RL32(p->buf)==0x800) {

        int bsm_s, bsm_e, inb_s, inb_e, ch;

        ch    = p->buf[264];

        bsm_s = p->buf[2048];

        inb_s = p->buf[2048+1];

        inb_e = p->buf[2048+210];

        bsm_e = p->buf[2048+211];

        if (ch != 1 && ch != 2)

            return 0;

        /* Check so that the redundant bsm bytes and info bytes are valid

         * the block size mode bytes have to be the same

         * the info bytes have to be the same

         */

        if (bsm_s == bsm_e && inb_s == inb_e)

            return AVPROBE_SCORE_MAX / 4 + 1;

    }

    return 0;

}

static int aea_read_header(AVFormatContext *s,

                           AVFormatParameters *ap)

{

    AVStream *st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    /* Parse the amount of channels and skip to pos 2048(0x800) */

    avio_skip(s->pb, 264);

    st->codec->channels = avio_r8(s->pb);

    avio_skip(s->pb, 1783);

    st->codec->codec_type     = AVMEDIA_TYPE_AUDIO;

    st->codec->codec_id       = CODEC_ID_ATRAC1;

    st->codec->sample_rate    = 44100;

    st->codec->bit_rate       = 292000;

    if (st->codec->channels != 1 && st->codec->channels != 2) {

        av_log(s,AV_LOG_ERROR,"Channels %d not supported!\n",st->codec->channels);

        return -1;

    }

    st->codec->channel_layout = (st->codec->channels == 1) ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

    st->codec->block_align = AT1_SU_SIZE * st->codec->channels;

    return 0;

}

static int aea_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);

    pkt->stream_index = 0;

    if (ret <= 0)

        return AVERROR(EIO);

    return ret;

}

AVInputFormat ff_aea_demuxer = {

    "aea",

    NULL_IF_CONFIG_SMALL("MD STUDIO audio"),

    0,

    aea_read_probe,

    aea_read_header,

    aea_read_packet,

    0,

    pcm_read_seek,

    .flags= AVFMT_GENERIC_INDEX,

    .extensions = "aea",

};