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ffmpeg / libavformat / tta.c @ d7fb5a18

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/*
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 * TTA demuxer
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 * Copyright (c) 2006 Alex Beregszaszi
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavcodec/bitstream.h"
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#include "avformat.h"
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typedef struct {
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    int totalframes, currentframe;
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} TTAContext;
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static int tta_probe(AVProbeData *p)
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{
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    const uint8_t *d = p->buf;
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    if (d[0] == 'T' && d[1] == 'T' && d[2] == 'A' && d[3] == '1')
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        return 80;
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    return 0;
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}
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static int tta_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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    TTAContext *c = s->priv_data;
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    AVStream *st;
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    int i, channels, bps, samplerate, datalen, framelen;
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    uint64_t framepos;
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    if (get_le32(s->pb) != ff_get_fourcc("TTA1"))
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        return -1; // not tta file
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    url_fskip(s->pb, 2); // FIXME: flags
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    channels = get_le16(s->pb);
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    bps = get_le16(s->pb);
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    samplerate = get_le32(s->pb);
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    if(samplerate <= 0 || samplerate > 1000000){
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        av_log(s, AV_LOG_ERROR, "nonsense samplerate\n");
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        return -1;
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    }
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    datalen = get_le32(s->pb);
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    if(datalen < 0){
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        av_log(s, AV_LOG_ERROR, "nonsense datalen\n");
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        return -1;
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    }
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    url_fskip(s->pb, 4); // header crc
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    framelen = samplerate*256/245;
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    c->totalframes = datalen / framelen + ((datalen % framelen) ? 1 : 0);
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    c->currentframe = 0;
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    if(c->totalframes >= UINT_MAX/sizeof(uint32_t)){
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        av_log(s, AV_LOG_ERROR, "totalframes too large\n");
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        return -1;
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    }
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    st = av_new_stream(s, 0);
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    if (!st)
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        return AVERROR(ENOMEM);
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    av_set_pts_info(st, 64, 1, samplerate);
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    st->start_time = 0;
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    st->duration = datalen;
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    framepos = url_ftell(s->pb) + 4*c->totalframes + 4;
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    for (i = 0; i < c->totalframes; i++) {
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        uint32_t size = get_le32(s->pb);
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        av_add_index_entry(st, framepos, i*framelen, size, 0, AVINDEX_KEYFRAME);
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        framepos += size;
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    }
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    url_fskip(s->pb, 4); // seektable crc
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    st->codec->codec_type = CODEC_TYPE_AUDIO;
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    st->codec->codec_id = CODEC_ID_TTA;
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    st->codec->channels = channels;
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    st->codec->sample_rate = samplerate;
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    st->codec->bits_per_coded_sample = bps;
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    st->codec->extradata_size = url_ftell(s->pb);
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    if(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE <= (unsigned)st->codec->extradata_size){
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        //this check is redundant as get_buffer should fail
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        av_log(s, AV_LOG_ERROR, "extradata_size too large\n");
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        return -1;
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    }
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    st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
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    url_fseek(s->pb, 0, SEEK_SET);
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    get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
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    return 0;
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}
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static int tta_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    TTAContext *c = s->priv_data;
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    AVStream *st = s->streams[0];
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    int size, ret;
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    // FIXME!
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    if (c->currentframe > c->totalframes)
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        return -1;
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    size = st->index_entries[c->currentframe].size;
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    ret = av_get_packet(s->pb, pkt, size);
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    pkt->dts = st->index_entries[c->currentframe++].timestamp;
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    return ret;
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}
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static int tta_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
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{
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    TTAContext *c = s->priv_data;
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    AVStream *st = s->streams[stream_index];
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    int index = av_index_search_timestamp(st, timestamp, flags);
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    if (index < 0)
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        return -1;
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    c->currentframe = index;
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    url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET);
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    return 0;
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}
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AVInputFormat tta_demuxer = {
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    "tta",
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    NULL_IF_CONFIG_SMALL("True Audio"),
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    sizeof(TTAContext),
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    tta_probe,
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    tta_read_header,
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    tta_read_packet,
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    NULL,
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    tta_read_seek,
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    .extensions = "tta",
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};