func: static int check_checksum(ByteIOContext *bc){
  
      unsigned long checksum= get_checksum(bc);
  
  //    return checksum != get_be32(bc);
  
  
  
      av_log(NULL, AV_LOG_ERROR, "%08X %08X\n", checksum, (int)get_be32(bc));
  
  
  
      return 0;
  
  }
  