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https://github.com/FFmpeg/FFmpeg.git
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96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/*
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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 "libavutil/channel_layout.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)
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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 = avformat_new_stream(s, NULL);
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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 = AV_CODEC_ID_ADPCM_IMA_APC;
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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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if (avio_rl32(pb)) {
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st->codec->channels = 2;
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st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
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} else {
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st->codec->channels = 1;
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st->codec->channel_layout = AV_CH_LAYOUT_MONO;
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}
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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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.name = "apc",
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.long_name = NULL_IF_CONFIG_SMALL("CRYO APC"),
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.read_probe = apc_probe,
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.read_header = apc_read_header,
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.read_packet = apc_read_packet,
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};
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