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3rdparty/ffmpeg-4.4.4/libavformat/derf.c 2.32 KB
09c2d08c   Hu Chunming   arm交付版
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  /*
   * DERF demuxer
   * Copyright (c) 2020 Paul B Mahol
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/intreadwrite.h"
  #include "avformat.h"
  #include "internal.h"
  #include "pcm.h"
  
  static int derf_probe(const AVProbeData *p)
  {
      if (AV_RL32(p->buf) != MKTAG('D','E','R','F'))
          return 0;
      if (AV_RL32(p->buf+4) != 1 && AV_RL32(p->buf+4) != 2)
          return 0;
  
      return AVPROBE_SCORE_MAX / 3 * 2;
  }
  
  static int derf_read_header(AVFormatContext *s)
  {
      unsigned data_size;
      AVIOContext *pb = s->pb;
      AVCodecParameters *par;
      AVStream *st;
  
      avio_skip(pb, 4);
  
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
      par              = st->codecpar;
      par->codec_type  = AVMEDIA_TYPE_AUDIO;
      par->codec_id    = AV_CODEC_ID_DERF_DPCM;
      par->format      = AV_SAMPLE_FMT_S16;
      par->channels    = avio_rl32(pb);
      if (par->channels != 1 && par->channels != 2)
          return AVERROR_INVALIDDATA;
      if (par->channels == 1)
          par->channel_layout = AV_CH_LAYOUT_MONO;
      else if (par->channels == 2)
          par->channel_layout = AV_CH_LAYOUT_STEREO;
      data_size = avio_rl32(pb);
      st->duration = data_size / par->channels;
      par->sample_rate = 22050;
      par->block_align = 1;
  
      avpriv_set_pts_info(st, 64, 1, par->sample_rate);
  
      return 0;
  }
  
  AVInputFormat ff_derf_demuxer = {
      .name           = "derf",
      .long_name      = NULL_IF_CONFIG_SMALL("Xilam DERF"),
      .read_probe     = derf_probe,
      .read_header    = derf_read_header,
      .read_packet    = ff_pcm_read_packet,
      .read_seek      = ff_pcm_read_seek,
      .extensions     = "adp",
  };