func: static int mtv_read_header(AVFormatContext *s)
  
  {
  
      MTVDemuxContext *mtv = s->priv_data;
  
      AVIOContext   *pb  = s->pb;
  
      AVStream        *st;
  
      unsigned int    audio_subsegments;
  
  
  
      avio_skip(pb, 3);
  
      mtv->file_size         = avio_rl32(pb);
  
      mtv->segments          = avio_rl32(pb);
  
      avio_skip(pb, 32);
  
      mtv->audio_identifier  = avio_rl24(pb);
  
      mtv->audio_br          = avio_rl16(pb);
  
      mtv->img_colorfmt      = avio_rl24(pb);
  
      mtv->img_bpp           = avio_r8(pb);
  
      mtv->img_width         = avio_rl16(pb);
  
      mtv->img_height        = avio_rl16(pb);
  
      mtv->img_segment_size  = avio_rl16(pb);
  
  
  
      /* Calculate width and height if missing from header */
  
  
  
      if(mtv->img_bpp>>3){
  
      if(!mtv->img_width && mtv->img_height)
  
          mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3)
  
                          / mtv->img_height;
  
  
  
      if(!mtv->img_height && mtv->img_width)
  
          mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3)
  
                          / mtv->img_width;
  
      }
  
      if(!mtv->img_height || !mtv->img_width || !mtv->img_segment_size){
  
          av_log(s, AV_LOG_ERROR, "width or height or segment_size is invalid and I cannot calculate them from other information\n");
  
          return AVERROR(EINVAL);
  
      }
  
  
  
      avio_skip(pb, 4);
  
      audio_subsegments = avio_rl16(pb);
  
  
  
      if (audio_subsegments == 0) {
  
          avpriv_request_sample(s, "MTV files without audio");
  
          return AVERROR_PATCHWELCOME;
  
      }
  
  
  
      mtv->full_segment_size =
  
          audio_subsegments * (MTV_AUDIO_PADDING_SIZE + MTV_ASUBCHUNK_DATA_SIZE) +
  
          mtv->img_segment_size;
  
      mtv->video_fps         = (mtv->audio_br / 4) / audio_subsegments;
  
  
  
      // FIXME Add sanity check here
  
  
  
      // all systems go! init decoders
  
  
  
      // video - raw rgb565
  
  
  
      st = avformat_new_stream(s, NULL);
  
      if(!st)
  
          return AVERROR(ENOMEM);
  
  
  
      avpriv_set_pts_info(st, 64, 1, mtv->video_fps);
  
      st->codec->codec_type      = AVMEDIA_TYPE_VIDEO;
  
      st->codec->codec_id        = AV_CODEC_ID_RAWVIDEO;
  
      st->codec->pix_fmt         = AV_PIX_FMT_RGB565BE;
  
      st->codec->width           = mtv->img_width;
  
      st->codec->height          = mtv->img_height;
  
      st->codec->sample_rate     = mtv->video_fps;
  
      st->codec->extradata       = av_strdup("BottomUp");
  
      st->codec->extradata_size  = 9;
  
  
  
      // audio - mp3
  
  
  
      st = avformat_new_stream(s, NULL);
  
      if(!st)
  
          return AVERROR(ENOMEM);
  
  
  
      avpriv_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE);
  
      st->codec->codec_type      = AVMEDIA_TYPE_AUDIO;
  
      st->codec->codec_id        = AV_CODEC_ID_MP3;
  
      st->codec->bit_rate        = mtv->audio_br;
  
      st->need_parsing           = AVSTREAM_PARSE_FULL;
  
  
  
      // Jump over header
  
  
  
      if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
  
          return AVERROR(EIO);
  
  
  
      return 0;
  
  
  
  }
  