text: /*
   * LVF demuxer
   * Copyright (c) 2012 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 "riff.h"
  
  static int lvf_probe(AVProbeData *p)
  {
      if (AV_RL32(p->buf) == MKTAG('L', 'V', 'F', 'F'))
          return AVPROBE_SCORE_EXTENSION;
      return 0;
  }
  
  static int lvf_read_header(AVFormatContext *s)
  {
      AVStream *st;
      int64_t next_offset;
      unsigned size, nb_streams, id;
  
      avio_skip(s->pb, 16);
      nb_streams = avio_rl32(s->pb);
      if (!nb_streams)
          return AVERROR_INVALIDDATA;
      if (nb_streams > 2) {
          avpriv_request_sample(s, "%d streams", nb_streams);
          return AVERROR_PATCHWELCOME;
      }
  
      avio_skip(s->pb, 1012);
  
      while (!url_feof(s->pb)) {
          id          = avio_rl32(s->pb);
          size        = avio_rl32(s->pb);
          next_offset = avio_tell(s->pb) + size;
  
          switch (id) {
          case MKTAG('0', '0', 'f', 'm'):
              st = avformat_new_stream(s, 0);
              if (!st)
                  return AVERROR(ENOMEM);
  
              st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
              avio_skip(s->pb, 4);
              st->codec->width      = avio_rl32(s->pb);
              st->codec->height     = avio_rl32(s->pb);
              avio_skip(s->pb, 4);
              st->codec->codec_tag  = avio_rl32(s->pb);
              st->codec->codec_id   = ff_codec_get_id(ff_codec_bmp_tags,
                                                      st->codec->codec_tag);
              avpriv_set_pts_info(st, 32, 1, 1000);
              break;
          case MKTAG('0', '1', 'f', 'm'):
              st = avformat_new_stream(s, 0);
              if (!st)
                  return AVERROR(ENOMEM);
  
              st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
              st->codec->codec_tag   = avio_rl16(s->pb);
              st->codec->channels    = avio_rl16(s->pb);
              st->codec->sample_rate = avio_rl16(s->pb);
              avio_skip(s->pb, 8);
              st->codec->bits_per_coded_sample = avio_r8(s->pb);
              st->codec->codec_id    = ff_codec_get_id(ff_codec_wav_tags,
                                                       st->codec->codec_tag);
              avpriv_set_pts_info(st, 32, 1, 1000);
              break;
          case 0:
              avio_seek(s->pb, 2048 + 8, SEEK_SET);
              return 0;
          default:
              avpriv_request_sample(s, "id %d", id);
              return AVERROR_PATCHWELCOME;
          }
  
          avio_seek(s->pb, next_offset, SEEK_SET);
      }
  
      return AVERROR_EOF;
  }
  
  static int lvf_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      unsigned size, flags, timestamp, id;
      int64_t pos;
      int ret, is_video = 0;
  
      pos = avio_tell(s->pb);
      while (!url_feof(s->pb)) {
          id    = avio_rl32(s->pb);
          size  = avio_rl32(s->pb);
  
          if (size == 0xFFFFFFFFu)
              return AVERROR_EOF;
  
          switch (id) {
          case MKTAG('0', '0', 'd', 'c'):
              is_video = 1;
          case MKTAG('0', '1', 'w', 'b'):
              if (size < 8)
                  return AVERROR_INVALIDDATA;
              timestamp = avio_rl32(s->pb);
              flags = avio_rl32(s->pb);
              ret = av_get_packet(s->pb, pkt, size - 8);
              if (flags & (1 << 12))
                  pkt->flags |= AV_PKT_FLAG_KEY;
              pkt->stream_index = is_video ? 0 : 1;
              pkt->pts          = timestamp;
              pkt->pos          = pos;
              return ret;
          default:
              ret = avio_skip(s->pb, size);
          }
  
          if (ret < 0)
              return ret;
      }
  
      return AVERROR_EOF;
  }
  
  AVInputFormat ff_lvf_demuxer = {
      .name        = "lvf",
      .long_name   = NULL_IF_CONFIG_SMALL("LVF"),
      .read_probe  = lvf_probe,
      .read_header = lvf_read_header,
      .read_packet = lvf_read_packet,
      .extensions  = "lvf",
      .flags       = AVFMT_GENERIC_INDEX,
  };
  