PeerStreamer

/*

 * VQF demuxer

 * Copyright (c) 2009 Vitor Sessak

 *

 * 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 "libavutil/intreadwrite.h"

typedef struct VqfContext {

    int frame_bit_len;

    uint8_t last_frame_bits;

    int remaining_bits;

} VqfContext;

static int vqf_probe(AVProbeData *probe_packet)

{

    if (AV_RL32(probe_packet->buf) != MKTAG('T','W','I','N'))

        return 0;

    if (!memcmp(probe_packet->buf + 4, "97012000", 8))

        return AVPROBE_SCORE_MAX;

    if (!memcmp(probe_packet->buf + 4, "00052200", 8))

        return AVPROBE_SCORE_MAX;

    return AVPROBE_SCORE_MAX/2;

}

static void add_metadata(AVFormatContext *s, const char *tag,

                         unsigned int tag_len, unsigned int remaining)

{

    int len = FFMIN(tag_len, remaining);

    char *buf;

    if (len == UINT_MAX)

        return;

    buf = av_malloc(len+1);

    if (!buf)

        return;

    avio_read(s->pb, buf, len);

    buf[len] = 0;

    av_metadata_set2(&s->metadata, tag, buf, AV_METADATA_DONT_STRDUP_VAL);

}

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

{

    VqfContext *c = s->priv_data;

    AVStream *st  = av_new_stream(s, 0);

    int chunk_tag;

    int rate_flag = -1;

    int header_size;

    int read_bitrate = 0;

    int size;

    if (!st)

        return AVERROR(ENOMEM);

    avio_skip(s->pb, 12);

    header_size = avio_rb32(s->pb);

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codec->codec_id   = CODEC_ID_TWINVQ;

    st->start_time = 0;

    do {

        int len;

        chunk_tag = avio_rl32(s->pb);

        if (chunk_tag == MKTAG('D','A','T','A'))

            break;

        len = avio_rb32(s->pb);

        if ((unsigned) len > INT_MAX/2) {

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

            return -1;

        }

        header_size -= 8;

        switch(chunk_tag){

        case MKTAG('C','O','M','M'):

            st->codec->channels = avio_rb32(s->pb) + 1;

            read_bitrate        = avio_rb32(s->pb);

            rate_flag           = avio_rb32(s->pb);

            avio_skip(s->pb, len-12);

            st->codec->bit_rate              = read_bitrate*1000;

            st->codec->bits_per_coded_sample = 16;

            break;

        case MKTAG('N','A','M','E'):

            add_metadata(s, "title"    , len, header_size);

            break;

        case MKTAG('(','c',')',' '):

            add_metadata(s, "copyright", len, header_size);

            break;

        case MKTAG('A','U','T','H'):

            add_metadata(s, "author"   , len, header_size);

            break;

        case MKTAG('A','L','B','M'):

            add_metadata(s, "album"    , len, header_size);

            break;

        case MKTAG('T','R','C','K'):

            add_metadata(s, "track"    , len, header_size);

            break;

        case MKTAG('C','O','M','T'):

            add_metadata(s, "comment"  , len, header_size);

            break;

        case MKTAG('F','I','L','E'):

            add_metadata(s, "filename" , len, header_size);

            break;

        case MKTAG('D','S','I','Z'):

            add_metadata(s, "size"     , len, header_size);

            break;

        case MKTAG('D','A','T','E'):

            add_metadata(s, "date"     , len, header_size);

            break;

        case MKTAG('G','E','N','R'):

            add_metadata(s, "genre"    , len, header_size);

            break;

        default:

            av_log(s, AV_LOG_ERROR, "Unknown chunk: %c%c%c%c\n",

                   ((char*)&chunk_tag)[0], ((char*)&chunk_tag)[1],

                   ((char*)&chunk_tag)[2], ((char*)&chunk_tag)[3]);

            avio_skip(s->pb, FFMIN(len, header_size));

            break;

        }

        header_size -= len;

    } while (header_size >= 0);

    switch (rate_flag) {

    case -1:

        av_log(s, AV_LOG_ERROR, "COMM tag not found!\n");

        return -1;

    case 44:

        st->codec->sample_rate = 44100;

        break;

    case 22:

        st->codec->sample_rate = 22050;

        break;

    case 11:

        st->codec->sample_rate = 11025;

        break;

    default:

        st->codec->sample_rate = rate_flag*1000;

        break;

    }

    switch (((st->codec->sample_rate/1000) << 8) +

            read_bitrate/st->codec->channels) {

    case (11<<8) + 8 :

    case (8 <<8) + 8 :

    case (11<<8) + 10:

    case (22<<8) + 32:

        size = 512;

        break;

    case (16<<8) + 16:

    case (22<<8) + 20:

    case (22<<8) + 24:

        size = 1024;

        break;

    case (44<<8) + 40:

    case (44<<8) + 48:

        size = 2048;

        break;

    default:

        av_log(s, AV_LOG_ERROR, "Mode not suported: %d Hz, %d kb/s.\n",

               st->codec->sample_rate, st->codec->bit_rate);

        return -1;

    }

    c->frame_bit_len = st->codec->bit_rate*size/st->codec->sample_rate;

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

    return 0;

}

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

{

    VqfContext *c = s->priv_data;

    int ret;

    int size = (c->frame_bit_len - c->remaining_bits + 7)>>3;

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

    pkt->stream_index = 0;

    if (av_new_packet(pkt, size+2) < 0)

        return AVERROR(EIO);

    pkt->data[0] = 8 - c->remaining_bits; // Number of bits to skip

    pkt->data[1] = c->last_frame_bits;

    ret = avio_read(s->pb, pkt->data+2, size);

    if (ret<=0) {

        av_free_packet(pkt);

        return AVERROR(EIO);

    }

    c->last_frame_bits = pkt->data[size+1];

    c->remaining_bits  = (size << 3) - c->frame_bit_len + c->remaining_bits;

    return size+2;

}

static int vqf_read_seek(AVFormatContext *s,

                         int stream_index, int64_t timestamp, int flags)

{

    VqfContext *c = s->priv_data;

    AVStream *st;

    int ret;

    int64_t pos;

    st = s->streams[stream_index];

    pos = av_rescale_rnd(timestamp * st->codec->bit_rate,

                         st->time_base.num,

                         st->time_base.den * (int64_t)c->frame_bit_len,

                         (flags & AVSEEK_FLAG_BACKWARD) ?

                                                   AV_ROUND_DOWN : AV_ROUND_UP);

    pos *= c->frame_bit_len;

    st->cur_dts = av_rescale(pos, st->time_base.den,

                             st->codec->bit_rate * (int64_t)st->time_base.num);

    if ((ret = avio_seek(s->pb, ((pos-7) >> 3) + s->data_offset, SEEK_SET)) < 0)

        return ret;

    c->remaining_bits = -7 - ((pos-7)&7);

    return 0;

}

AVInputFormat ff_vqf_demuxer = {

    "vqf",

    NULL_IF_CONFIG_SMALL("Nippon Telegraph and Telephone Corporation (NTT) TwinVQ"),

    sizeof(VqfContext),

    vqf_probe,

    vqf_read_header,

    vqf_read_packet,

    NULL,

    vqf_read_seek,

    .extensions = "vqf",

};