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ffmpeg-4.2.2/libavformat/ivfdec.c 2.65 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * Copyright (c) 2010 David Conrad
   *
   * 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"
  #include "riff.h"
  #include "libavutil/intreadwrite.h"
  
  static int probe(const AVProbeData *p)
  {
      if (AV_RL32(p->buf) == MKTAG('D','K','I','F')
          && !AV_RL16(p->buf+4) && AV_RL16(p->buf+6) == 32)
          return AVPROBE_SCORE_MAX-2;
  
      return 0;
  }
  
  static int read_header(AVFormatContext *s)
  {
      AVStream *st;
      AVRational time_base;
  
      avio_rl32(s->pb); // DKIF
      avio_rl16(s->pb); // version
      avio_rl16(s->pb); // header size
  
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
  
      st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
      st->codecpar->codec_tag  = avio_rl32(s->pb);
      st->codecpar->codec_id   = ff_codec_get_id(ff_codec_bmp_tags, st->codecpar->codec_tag);
      st->codecpar->width      = avio_rl16(s->pb);
      st->codecpar->height     = avio_rl16(s->pb);
      time_base.den         = avio_rl32(s->pb);
      time_base.num         = avio_rl32(s->pb);
      st->duration          = avio_rl64(s->pb);
  
      st->need_parsing      = AVSTREAM_PARSE_HEADERS;
  
      if (!time_base.den || !time_base.num) {
          av_log(s, AV_LOG_ERROR, "Invalid frame rate\n");
          return AVERROR_INVALIDDATA;
      }
  
      avpriv_set_pts_info(st, 64, time_base.num, time_base.den);
  
      return 0;
  }
  
  static int read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      int ret, size = avio_rl32(s->pb);
      int64_t   pts = avio_rl64(s->pb);
  
      ret = av_get_packet(s->pb, pkt, size);
      pkt->stream_index = 0;
      pkt->pts          = pts;
      pkt->pos         -= 12;
  
      return ret;
  }
  
  AVInputFormat ff_ivf_demuxer = {
      .name           = "ivf",
      .long_name      = NULL_IF_CONFIG_SMALL("On2 IVF"),
      .read_probe     = probe,
      .read_header    = read_header,
      .read_packet    = read_packet,
      .flags          = AVFMT_GENERIC_INDEX,
      .codec_tag      = (const AVCodecTag* const []){ ff_codec_bmp_tags, 0 },
  };