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			100 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			100 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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| 
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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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| 
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| static int avr_probe(const 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 0;
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| 
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|     if (!AV_RB16(p->buf+12) || AV_RB16(p->buf+12) > 256) // channels
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|         return AVPROBE_SCORE_EXTENSION/2;
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|     if (AV_RB16(p->buf+14) > 256) // bps
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|         return AVPROBE_SCORE_EXTENSION/2;
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| 
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|     return AVPROBE_SCORE_EXTENSION;
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| }
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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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| 
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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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| 
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|     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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| 
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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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| 
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|     chan = avio_rb16(s->pb);
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|     if (!chan) {
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|         st->codecpar->channels = 1;
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|     } else if (chan == 0xFFFFu) {
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|         st->codecpar->channels = 2;
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|     } else {
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|         avpriv_request_sample(s, "chan %d", chan);
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|         return AVERROR_PATCHWELCOME;
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|     }
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| 
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|     st->codecpar->bits_per_coded_sample = bps = avio_rb16(s->pb);
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| 
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|     sign = avio_rb16(s->pb);
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| 
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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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| 
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|     st->codecpar->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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| 
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|     st->codecpar->codec_id = ff_get_pcm_codec_id(bps, 0, 1, sign);
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|     if (st->codecpar->codec_id == AV_CODEC_ID_NONE) {
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|         avpriv_request_sample(s, "Bps %d and sign %d", bps, sign);
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|         return AVERROR_PATCHWELCOME;
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|     }
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| 
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|     st->codecpar->block_align = bps * st->codecpar->channels / 8;
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| 
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|     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
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|     return 0;
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| }
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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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