func: static int compare_codec_desc(const void *a, const void *b)
  
  {
  
      const AVCodecDescriptor * const *da = a;
  
      const AVCodecDescriptor * const *db = b;
  
  
  
      return (*da)->type != (*db)->type ? (*da)->type - (*db)->type :
  
             strcmp((*da)->name, (*db)->name);
  
  }
  