text: /*
   * VC1 Test Bitstreams Format Demuxer
   * Copyright (c) 2006, 2008 Konstantin Shishkov
   *
   * 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
   */
  
  /**
   * @file
   * VC1 test bitstream file demuxer
   * by Konstantin Shishkov
   * Format specified in SMPTE standard 421 Annex L
   */
  
  #include "libavutil/intreadwrite.h"
  #include "avformat.h"
  #include "internal.h"
  
  #define VC1_EXTRADATA_SIZE 4
  
  static int vc1t_probe(AVProbeData *p)
  {
      if (p->buf_size < 24)
          return 0;
      if (p->buf[3] != 0xC5 || AV_RL32(&p->buf[4]) != 4 || AV_RL32(&p->buf[20]) != 0xC)
          return 0;
  
      return AVPROBE_SCORE_EXTENSION;
  }
  
  static int vc1t_read_header(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      AVStream *st;
      int frames;
      uint32_t fps;
  
      frames = avio_rl24(pb);
      if(avio_r8(pb) != 0xC5 || avio_rl32(pb) != 4)
          return -1;
  
      /* init video codec */
      st = avformat_new_stream(s, NULL);
      if (!st)
          return -1;
  
      st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
      st->codec->codec_id = AV_CODEC_ID_WMV3;
  
      st->codec->extradata = av_malloc(VC1_EXTRADATA_SIZE);
      st->codec->extradata_size = VC1_EXTRADATA_SIZE;
      avio_read(pb, st->codec->extradata, VC1_EXTRADATA_SIZE);
      st->codec->height = avio_rl32(pb);
      st->codec->width = avio_rl32(pb);
      if(avio_rl32(pb) != 0xC)
          return -1;
      avio_skip(pb, 8);
      fps = avio_rl32(pb);
      if(fps == 0xFFFFFFFF)
          avpriv_set_pts_info(st, 32, 1, 1000);
      else{
          if (!fps) {
              av_log(s, AV_LOG_ERROR, "Zero FPS specified, defaulting to 1 FPS\n");
              fps = 1;
          }
          avpriv_set_pts_info(st, 24, 1, fps);
          st->duration = frames;
      }
  
      return 0;
  }
  
  static int vc1t_read_packet(AVFormatContext *s,
                             AVPacket *pkt)
  {
      AVIOContext *pb = s->pb;
      int frame_size;
      int keyframe = 0;
      uint32_t pts;
  
      if(url_feof(pb))
          return AVERROR(EIO);
  
      frame_size = avio_rl24(pb);
      if(avio_r8(pb) & 0x80)
          keyframe = 1;
      pts = avio_rl32(pb);
      if(av_get_packet(pb, pkt, frame_size) < 0)
          return AVERROR(EIO);
      if(s->streams[0]->time_base.den == 1000)
          pkt->pts = pts;
      pkt->flags |= keyframe ? AV_PKT_FLAG_KEY : 0;
      pkt->pos -= 8;
  
      return pkt->size;
  }
  
  AVInputFormat ff_vc1t_demuxer = {
      .name           = "vc1test",
      .long_name      = NULL_IF_CONFIG_SMALL("VC-1 test bitstream"),
      .read_probe     = vc1t_probe,
      .read_header    = vc1t_read_header,
      .read_packet    = vc1t_read_packet,
      .flags          = AVFMT_GENERIC_INDEX,
  };
  