PeerStreamer

/*

 * Creative Voice File demuxer.

 * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>

 *

 * 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

 */

#include "libavutil/intreadwrite.h"

#include "voc.h"

#include "internal.h"

static int voc_probe(AVProbeData *p)

{

    int version, check;

    if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))

        return 0;

    version = AV_RL16(p->buf + 22);

    check = AV_RL16(p->buf + 24);

    if (~version + 0x1234 != check)

        return 10;

    return AVPROBE_SCORE_MAX;

}

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

{

    VocDecContext *voc = s->priv_data;

    AVIOContext *pb = s->pb;

    int header_size;

    AVStream *st;

    avio_seek(pb, 20, SEEK_CUR);

    header_size = avio_rl16(pb) - 22;

    if (header_size != 4) {

        av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);

        return AVERROR(ENOSYS);

    }

    avio_seek(pb, header_size, SEEK_CUR);

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    voc->remaining_size = 0;

    return 0;

}

int

voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)

{

    VocDecContext *voc = s->priv_data;

    AVCodecContext *dec = st->codec;

    AVIOContext *pb = s->pb;

    VocType type;

    int size, tmp_codec=-1;

    int sample_rate = 0;

    int channels = 1;

    while (!voc->remaining_size) {

        type = avio_r8(pb);

        if (type == VOC_TYPE_EOF)

            return AVERROR(EIO);

        voc->remaining_size = avio_rl24(pb);

        if (!voc->remaining_size) {

            if (url_is_streamed(s->pb))

                return AVERROR(EIO);

            voc->remaining_size = url_fsize(pb) - avio_tell(pb);

        }

        max_size -= 4;

        switch (type) {

        case VOC_TYPE_VOICE_DATA:

            dec->sample_rate = 1000000 / (256 - avio_r8(pb));

            if (sample_rate)

                dec->sample_rate = sample_rate;

            dec->channels = channels;

            tmp_codec = avio_r8(pb);

            dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);

            voc->remaining_size -= 2;

            max_size -= 2;

            channels = 1;

            break;

        case VOC_TYPE_VOICE_DATA_CONT:

            break;

        case VOC_TYPE_EXTENDED:

            sample_rate = avio_rl16(pb);

            avio_r8(pb);

            channels = avio_r8(pb) + 1;

            sample_rate = 256000000 / (channels * (65536 - sample_rate));

            voc->remaining_size = 0;

            max_size -= 4;

            break;

        case VOC_TYPE_NEW_VOICE_DATA:

            dec->sample_rate = avio_rl32(pb);

            dec->bits_per_coded_sample = avio_r8(pb);

            dec->channels = avio_r8(pb);

            tmp_codec = avio_rl16(pb);

            avio_seek(pb, 4, SEEK_CUR);

            voc->remaining_size -= 12;

            max_size -= 12;

            break;

        default:

            avio_seek(pb, voc->remaining_size, SEEK_CUR);

            max_size -= voc->remaining_size;

            voc->remaining_size = 0;

            break;

        }

    }

    if (tmp_codec >= 0) {

        tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec);

        if (dec->codec_id == CODEC_ID_NONE)

            dec->codec_id = tmp_codec;

        else if (dec->codec_id != tmp_codec)

            av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n");

        if (dec->codec_id == CODEC_ID_NONE) {

            if (s->audio_codec_id == CODEC_ID_NONE) {

                av_log(s, AV_LOG_ERROR, "unknown codec tag\n");

                return AVERROR(EINVAL);

            }

            av_log(s, AV_LOG_WARNING, "unknown codec tag\n");

        }

    }

    dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample;

    if (max_size <= 0)

        max_size = 2048;

    size = FFMIN(voc->remaining_size, max_size);

    voc->remaining_size -= size;

    return av_get_packet(pb, pkt, size);

}

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

{

    return voc_get_packet(s, pkt, s->streams[0], 0);

}

AVInputFormat ff_voc_demuxer = {

    "voc",

    NULL_IF_CONFIG_SMALL("Creative Voice file format"),

    sizeof(VocDecContext),

    voc_probe,

    voc_read_header,

    voc_read_packet,

    .codec_tag=(const AVCodecTag* const []){ff_voc_codec_tags, 0},

};