PeerStreamer

/*

 * Electronic Arts .cdata file Demuxer

 * Copyright (c) 2007 Peter Ross

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

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

 */

/**

 * @file

 * Electronic Arts cdata Format Demuxer

 * by Peter Ross (pross@xvid.org)

 *

 * Technical details here:

 *  http://wiki.multimedia.cx/index.php?title=EA_Command_And_Conquer_3_Audio_Codec

 */

#include "avformat.h"

typedef struct {

  unsigned int channels;

  unsigned int audio_pts;

} CdataDemuxContext;

static int cdata_probe(AVProbeData *p)

{

    const uint8_t *b = p->buf;

    if (b[0] == 0x04 && (b[1] == 0x00 || b[1] == 0x04 || b[1] == 0x0C))

        return AVPROBE_SCORE_MAX/8;

    return 0;

}

static int cdata_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    CdataDemuxContext *cdata = s->priv_data;

    AVIOContext *pb = s->pb;

    unsigned int sample_rate, header;

    AVStream *st;

    header = avio_rb16(pb);

    switch (header) {

        case 0x0400: cdata->channels = 1; break;

        case 0x0404: cdata->channels = 2; break;

        case 0x040C: cdata->channels = 4; break;

        default:

            av_log(s, AV_LOG_INFO, "unknown header 0x%04x\n", header);

            return -1;

    };

    sample_rate = avio_rb16(pb);

    avio_skip(pb, 12);

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codec->codec_tag = 0; /* no fourcc */

    st->codec->codec_id = CODEC_ID_ADPCM_EA_XAS;

    st->codec->channels = cdata->channels;

    st->codec->sample_rate = sample_rate;

    av_set_pts_info(st, 64, 1, sample_rate);

    cdata->audio_pts = 0;

    return 0;

}

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

{

    CdataDemuxContext *cdata = s->priv_data;

    int packet_size = 76*cdata->channels;

    int ret = av_get_packet(s->pb, pkt, packet_size);

    if (ret < 0)

        return ret;

    pkt->pts = cdata->audio_pts++;

    return 0;

}

AVInputFormat ff_ea_cdata_demuxer = {

    "ea_cdata",

    NULL_IF_CONFIG_SMALL("Electronic Arts cdata"),

    sizeof(CdataDemuxContext),

    cdata_probe,

    cdata_read_header,

    cdata_read_packet,

    .extensions = "cdata",

};