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ffmpeg-4.2.2/libavformat/svag.c 2.44 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * SVAG demuxer
   * Copyright (c) 2015 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 "avformat.h"
  #include "internal.h"
  
  static int svag_probe(const AVProbeData *p)
  {
      if (memcmp(p->buf, "Svag", 4))
          return 0;
  
      return AVPROBE_SCORE_MAX;
  }
  
  static int svag_read_header(AVFormatContext *s)
  {
      unsigned size, align;
      AVStream *st;
  
      avio_skip(s->pb, 4);
  
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
      size                   = avio_rl32(s->pb);
      st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
      st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_PSX;
      st->codecpar->sample_rate = avio_rl32(s->pb);
      if (st->codecpar->sample_rate <= 0)
          return AVERROR_INVALIDDATA;
      st->codecpar->channels    = avio_rl32(s->pb);
      if (st->codecpar->channels <= 0 || st->codecpar->channels > 8)
          return AVERROR_INVALIDDATA;
      st->duration           = size / (16 * st->codecpar->channels) * 28;
      align                  = avio_rl32(s->pb);
      if (align <= 0 || align > INT_MAX / st->codecpar->channels)
          return AVERROR_INVALIDDATA;
      st->codecpar->block_align = align * st->codecpar->channels;
      avio_skip(s->pb, 0x800 - avio_tell(s->pb));
      avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
  
      return 0;
  }
  
  static int svag_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      AVCodecParameters *par = s->streams[0]->codecpar;
  
      return av_get_packet(s->pb, pkt, par->block_align);
  }
  
  AVInputFormat ff_svag_demuxer = {
      .name           = "svag",
      .long_name      = NULL_IF_CONFIG_SMALL("Konami PS2 SVAG"),
      .read_probe     = svag_probe,
      .read_header    = svag_read_header,
      .read_packet    = svag_read_packet,
      .extensions     = "svag",
  };