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ffmpeg / libavformat / apc.c @ acaceca2

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/*
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 * CRYO APC audio format demuxer
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 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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 <string.h>
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#include "avformat.h"
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static int apc_probe(AVProbeData *p)
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{
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    if (!strncmp(p->buf, "CRYO_APC", 8))
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        return AVPROBE_SCORE_MAX;
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    return 0;
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}
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static int apc_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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    AVIOContext *pb = s->pb;
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    AVStream *st;
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    avio_rl32(pb); /* CRYO */
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    avio_rl32(pb); /* _APC */
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    avio_rl32(pb); /* 1.20 */
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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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    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
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    st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
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    avio_rl32(pb); /* number of samples */
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    st->codec->sample_rate = avio_rl32(pb);
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    st->codec->extradata_size = 2 * 4;
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    st->codec->extradata = av_malloc(st->codec->extradata_size +
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                                     FF_INPUT_BUFFER_PADDING_SIZE);
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    if (!st->codec->extradata)
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        return AVERROR(ENOMEM);
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    /* initial predictor values for adpcm decoder */
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    avio_read(pb, st->codec->extradata, 2 * 4);
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    st->codec->channels = 1;
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    if (avio_rl32(pb))
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        st->codec->channels = 2;
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    st->codec->bits_per_coded_sample = 4;
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    st->codec->bit_rate = st->codec->bits_per_coded_sample * st->codec->channels
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                          * st->codec->sample_rate;
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    st->codec->block_align = 1;
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    return 0;
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}
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#define MAX_READ_SIZE 4096
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static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
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        return AVERROR(EIO);
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    pkt->stream_index = 0;
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    return 0;
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}
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AVInputFormat ff_apc_demuxer = {
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    "apc",
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    NULL_IF_CONFIG_SMALL("CRYO APC format"),
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    0,
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    apc_probe,
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    apc_read_header,
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    apc_read_packet,
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};