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	a085cfa654
	
	
	
		
			
			It is only used by demuxers (although it is hypothetically possible that some day e.g. a protocol might need it, but that is unlikely given that they don't deal with AVCodecParameters). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
		
			
				
	
	
		
			89 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			2.5 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 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 <string.h>
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| 
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| #include "libavutil/channel_layout.h"
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| #include "avformat.h"
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| #include "demux.h"
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| 
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| static int apc_probe(const 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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| 
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|     return 0;
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| }
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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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|     int ret;
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|     int channels;
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| 
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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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| 
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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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|     st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
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| 
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|     avio_rl32(pb); /* number of samples */
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|     st->codecpar->sample_rate = avio_rl32(pb);
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| 
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|     /* initial predictor values for adpcm decoder */
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|     if ((ret = ff_get_extradata(s, st->codecpar, pb, 2 * 4)) < 0)
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|         return ret;
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| 
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|     channels = !!avio_rl32(pb) + 1;
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|     av_channel_layout_default(&st->codecpar->ch_layout, channels);
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| 
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|     st->codecpar->bits_per_coded_sample = 4;
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|     st->codecpar->bit_rate = (int64_t)st->codecpar->bits_per_coded_sample * channels
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|                           * st->codecpar->sample_rate;
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|     st->codecpar->block_align = 1;
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| 
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|     return 0;
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| }
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| 
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| #define MAX_READ_SIZE 4096
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| 
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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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| 
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| const 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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