func: static int get_riff(AVFormatContext *s, AVIOContext *pb)
  
  {
  
      AVIContext *avi = s->priv_data;
  
      char header[8];
  
      int i;
  
  
  
      /* check RIFF header */
  
      avio_read(pb, header, 4);
  
      avi->riff_end = avio_rl32(pb);  /* RIFF chunk size */
  
      avi->riff_end += avio_tell(pb); /* RIFF chunk end */
  
      avio_read(pb, header+4, 4);
  
  
  
      for(i=0; avi_headers[i][0]; i++)
  
          if(!memcmp(header, avi_headers[i], 8))
  
              break;
  
      if(!avi_headers[i][0])
  
          return -1;
  
  
  
      if(header[7] == 0x19)
  
          av_log(s, AV_LOG_INFO, "This file has been generated by a totally broken muxer.\n");
  
  
  
      return 0;
  
  }
  