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  1. /*
  2.  * AVR demuxer
  3.  * Copyright (c) 2012 Paul B Mahol
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include "libavutil/intreadwrite.h"
  23. #include "avformat.h"
  24. #include "internal.h"
  25. #include "pcm.h"
  26.  
  27. static int avr_probe(AVProbeData *p)
  28. {
  29.     if (AV_RL32(p->buf) == MKTAG('2', 'B', 'I', 'T'))
  30.         return AVPROBE_SCORE_EXTENSION;
  31.     return 0;
  32. }
  33.  
  34. static int avr_read_header(AVFormatContext *s)
  35. {
  36.     uint16_t chan, sign, bps;
  37.     AVStream *st;
  38.  
  39.     st = avformat_new_stream(s, NULL);
  40.     if (!st)
  41.         return AVERROR(ENOMEM);
  42.  
  43.     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  44.  
  45.     avio_skip(s->pb, 4); // magic
  46.     avio_skip(s->pb, 8); // sample_name
  47.  
  48.     chan = avio_rb16(s->pb);
  49.     if (!chan) {
  50.         st->codec->channels = 1;
  51.     } else if (chan == 0xFFFFu) {
  52.         st->codec->channels = 2;
  53.     } else {
  54.         avpriv_request_sample(s, "chan %d", chan);
  55.         return AVERROR_PATCHWELCOME;
  56.     }
  57.  
  58.     st->codec->bits_per_coded_sample = bps = avio_rb16(s->pb);
  59.  
  60.     sign = avio_rb16(s->pb);
  61.  
  62.     avio_skip(s->pb, 2); // loop
  63.     avio_skip(s->pb, 2); // midi
  64.     avio_skip(s->pb, 1); // replay speed
  65.  
  66.     st->codec->sample_rate = avio_rb24(s->pb);
  67.     avio_skip(s->pb, 4 * 3);
  68.     avio_skip(s->pb, 2 * 3);
  69.     avio_skip(s->pb, 20);
  70.     avio_skip(s->pb, 64);
  71.  
  72.     st->codec->codec_id = ff_get_pcm_codec_id(bps, 0, 1, sign);
  73.     if (st->codec->codec_id == AV_CODEC_ID_NONE) {
  74.         avpriv_request_sample(s, "Bps %d and sign %d", bps, sign);
  75.         return AVERROR_PATCHWELCOME;
  76.     }
  77.  
  78.     st->codec->block_align = bps * st->codec->channels / 8;
  79.  
  80.     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
  81.     return 0;
  82. }
  83.  
  84. AVInputFormat ff_avr_demuxer = {
  85.     .name           = "avr",
  86.     .long_name      = NULL_IF_CONFIG_SMALL("AVR (Audio Visual Research)"),
  87.     .read_probe     = avr_probe,
  88.     .read_header    = avr_read_header,
  89.     .read_packet    = ff_pcm_read_packet,
  90.     .read_seek      = ff_pcm_read_seek,
  91.     .extensions     = "avr",
  92.     .flags          = AVFMT_GENERIC_INDEX,
  93. };
  94.