PeerStreamer

/*

 * amr file format

 * Copyright (c) 2001 ffmpeg project

 *

 * 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

 */

/*

Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267

Only mono files are supported.

*/

#include "avformat.h"

static const char AMR_header [] = "#!AMR\n";

static const char AMRWB_header [] = "#!AMR-WB\n";

#if CONFIG_AMR_MUXER

static int amr_write_header(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    AVCodecContext *enc = s->streams[0]->codec;

    s->priv_data = NULL;

    if (enc->codec_id == CODEC_ID_AMR_NB)

    {

        avio_write(pb, AMR_header,   sizeof(AMR_header)   - 1); /* magic number */

    }

    else if(enc->codec_id == CODEC_ID_AMR_WB)

    {

        avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */

    }

    else

    {

        return -1;

    }

    put_flush_packet(pb);

    return 0;

}

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

{

    avio_write(s->pb, pkt->data, pkt->size);

    put_flush_packet(s->pb);

    return 0;

}

#endif /* CONFIG_AMR_MUXER */

static int amr_probe(AVProbeData *p)

{

    //Only check for "#!AMR" which could be amr-wb, amr-nb.

    //This will also trigger multichannel files: "#!AMR_MC1.0\n" and

    //"#!AMR-WB_MC1.0\n" (not supported)

    if(memcmp(p->buf,AMR_header,5)==0)

        return AVPROBE_SCORE_MAX;

    else

        return 0;

}

/* amr input */

static int amr_read_header(AVFormatContext *s,

                           AVFormatParameters *ap)

{

    AVIOContext *pb = s->pb;

    AVStream *st;

    uint8_t header[9];

    avio_read(pb, header, 6);

    st = av_new_stream(s, 0);

    if (!st)

    {

        return AVERROR(ENOMEM);

    }

    if(memcmp(header,AMR_header,6)!=0)

    {

        avio_read(pb, header+6, 3);

        if(memcmp(header,AMRWB_header,9)!=0)

        {

            return -1;

        }

        st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');

        st->codec->codec_id = CODEC_ID_AMR_WB;

        st->codec->sample_rate = 16000;

        st->codec->frame_size = 320;

    }

    else

    {

        st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');

        st->codec->codec_id = CODEC_ID_AMR_NB;

        st->codec->sample_rate = 8000;

        st->codec->frame_size = 160;

    }

    st->codec->channels = 1;

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

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

    return 0;

}

static int amr_read_packet(AVFormatContext *s,

                          AVPacket *pkt)

{

    AVCodecContext *enc = s->streams[0]->codec;

    int read, size = 0, toc, mode;

    if (s->pb->eof_reached)

    {

        return AVERROR(EIO);

    }

//FIXME this is wrong, this should rather be in a AVParset

    toc=avio_r8(s->pb);

    mode = (toc >> 3) & 0x0F;

    if (enc->codec_id == CODEC_ID_AMR_NB)

    {

        static const uint8_t packed_size[16] = {12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0};

        size=packed_size[mode]+1;

    }

    else if(enc->codec_id == CODEC_ID_AMR_WB)

    {

        static uint8_t packed_size[16] = {18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1};

        size=packed_size[mode];

    }

    else

    {

        assert(0);

    }

    if ( (size==0) || av_new_packet(pkt, size))

    {

        return AVERROR(EIO);

    }

    pkt->stream_index = 0;

    pkt->pos= avio_tell(s->pb);

    pkt->data[0]=toc;

    pkt->duration= enc->codec_id == CODEC_ID_AMR_NB ? 160 : 320;

    read = avio_read(s->pb, pkt->data+1, size-1);

    if (read != size-1)

    {

        av_free_packet(pkt);

        return AVERROR(EIO);

    }

    return 0;

}

#if CONFIG_AMR_DEMUXER

AVInputFormat ff_amr_demuxer = {

    "amr",

    NULL_IF_CONFIG_SMALL("3GPP AMR file format"),

    0, /*priv_data_size*/

    amr_probe,

    amr_read_header,

    amr_read_packet,

    NULL,

};

#endif

#if CONFIG_AMR_MUXER

AVOutputFormat ff_amr_muxer = {

    "amr",

    NULL_IF_CONFIG_SMALL("3GPP AMR file format"),

    "audio/amr",

    "amr",

    0,

    CODEC_ID_AMR_NB,

    CODEC_ID_NONE,

    amr_write_header,

    amr_write_packet,

};

#endif