PeerStreamer

/*

 * TTA demuxer

 * Copyright (c) 2006 Alex Beregszaszi

 *

 * 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 "libavcodec/get_bits.h"

#include "avformat.h"

#include "id3v1.h"

typedef struct {

    int totalframes, currentframe;

} TTAContext;

static int tta_probe(AVProbeData *p)

{

    const uint8_t *d = p->buf;

    if (d[0] == 'T' && d[1] == 'T' && d[2] == 'A' && d[3] == '1')

        return 80;

    return 0;

}

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

{

    TTAContext *c = s->priv_data;

    AVStream *st;

    int i, channels, bps, samplerate, datalen, framelen;

    uint64_t framepos, start_offset;

    if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))

        ff_id3v1_read(s);

    start_offset = avio_tell(s->pb);

    if (avio_rl32(s->pb) != AV_RL32("TTA1"))

        return -1; // not tta file

    avio_seek(s->pb, 2, SEEK_CUR); // FIXME: flags

    channels = avio_rl16(s->pb);

    bps = avio_rl16(s->pb);

    samplerate = avio_rl32(s->pb);

    if(samplerate <= 0 || samplerate > 1000000){

        av_log(s, AV_LOG_ERROR, "nonsense samplerate\n");

        return -1;

    }

    datalen = avio_rl32(s->pb);

    if(datalen < 0){

        av_log(s, AV_LOG_ERROR, "nonsense datalen\n");

        return -1;

    }

    avio_seek(s->pb, 4, SEEK_CUR); // header crc

    framelen = samplerate*256/245;

    c->totalframes = datalen / framelen + ((datalen % framelen) ? 1 : 0);

    c->currentframe = 0;

    if(c->totalframes >= UINT_MAX/sizeof(uint32_t)){

        av_log(s, AV_LOG_ERROR, "totalframes too large\n");

        return -1;

    }

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    av_set_pts_info(st, 64, 1, samplerate);

    st->start_time = 0;

    st->duration = datalen;

    framepos = avio_tell(s->pb) + 4*c->totalframes + 4;

    for (i = 0; i < c->totalframes; i++) {

        uint32_t size = avio_rl32(s->pb);

        av_add_index_entry(st, framepos, i*framelen, size, 0, AVINDEX_KEYFRAME);

        framepos += size;

    }

    avio_seek(s->pb, 4, SEEK_CUR); // seektable crc

    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    st->codec->codec_id = CODEC_ID_TTA;

    st->codec->channels = channels;

    st->codec->sample_rate = samplerate;

    st->codec->bits_per_coded_sample = bps;

    st->codec->extradata_size = avio_tell(s->pb) - start_offset;

    if(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE <= (unsigned)st->codec->extradata_size){

        //this check is redundant as avio_read should fail

        av_log(s, AV_LOG_ERROR, "extradata_size too large\n");

        return -1;

    }

    st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);

    avio_seek(s->pb, start_offset, SEEK_SET);

    avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);

    return 0;

}

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

{

    TTAContext *c = s->priv_data;

    AVStream *st = s->streams[0];

    int size, ret;

    // FIXME!

    if (c->currentframe > c->totalframes)

        return -1;

    size = st->index_entries[c->currentframe].size;

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

    pkt->dts = st->index_entries[c->currentframe++].timestamp;

    return ret;

}

static int tta_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)

{

    TTAContext *c = s->priv_data;

    AVStream *st = s->streams[stream_index];

    int index = av_index_search_timestamp(st, timestamp, flags);

    if (index < 0)

        return -1;

    c->currentframe = index;

    avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET);

    return 0;

}

AVInputFormat ff_tta_demuxer = {

    "tta",

    NULL_IF_CONFIG_SMALL("True Audio"),

    sizeof(TTAContext),

    tta_probe,

    tta_read_header,

    tta_read_packet,

    NULL,

    tta_read_seek,

    .extensions = "tta",

};