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https://github.com/FFmpeg/FFmpeg.git
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101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/*
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* AVR demuxer
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* Copyright (c) 2012 Paul B Mahol
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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 "libavutil/intreadwrite.h"
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#include "avformat.h"
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#include "internal.h"
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#include "pcm.h"
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static int avr_probe(AVProbeData *p)
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{
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if (AV_RL32(p->buf) == MKTAG('2', 'B', 'I', 'T'))
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return AVPROBE_SCORE_MAX / 2;
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return 0;
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}
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static int avr_read_header(AVFormatContext *s)
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{
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uint16_t chan, sign, bps;
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AVStream *st;
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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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avio_skip(s->pb, 4); // magic
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avio_skip(s->pb, 8); // sample_name
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chan = avio_rb16(s->pb);
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if (!chan) {
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st->codec->channels = 1;
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} else if (chan == 0xFFFFu) {
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st->codec->channels = 2;
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} else {
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av_log_ask_for_sample(s, "unknown number of channels\n");
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return AVERROR_PATCHWELCOME;
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}
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st->codec->bits_per_coded_sample = bps = avio_rb16(s->pb);
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sign = avio_rb16(s->pb);
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avio_skip(s->pb, 2); // loop
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avio_skip(s->pb, 2); // midi
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avio_skip(s->pb, 1); // replay speed
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st->codec->sample_rate = avio_rb24(s->pb);
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avio_skip(s->pb, 4 * 3);
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avio_skip(s->pb, 2 * 3);
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avio_skip(s->pb, 20);
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avio_skip(s->pb, 64);
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if (!sign && bps == 8) {
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st->codec->codec_id = AV_CODEC_ID_PCM_U8;
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} else if (!sign && bps == 16) {
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st->codec->codec_id = AV_CODEC_ID_PCM_U16BE;
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} else if (sign == 0xFFFFu && bps == 8) {
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st->codec->codec_id = AV_CODEC_ID_PCM_S8;
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} else if (sign == 0xFFFFu && bps == 16) {
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st->codec->codec_id = AV_CODEC_ID_PCM_S16BE;
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} else {
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av_log_ask_for_sample(s, "unknown bits per sample\n");
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return AVERROR_PATCHWELCOME;
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}
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st->codec->block_align = bps * st->codec->channels / 8;
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avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
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return 0;
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}
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AVInputFormat ff_avr_demuxer = {
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.name = "avr",
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.long_name = NULL_IF_CONFIG_SMALL("AVR (Audio Visual Research)"),
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.read_probe = avr_probe,
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.read_header = avr_read_header,
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.read_packet = ff_pcm_read_packet,
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.read_seek = ff_pcm_read_seek,
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.extensions = "avr",
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.flags = AVFMT_GENERIC_INDEX,
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};
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