private void downloadSingleVideoAsVideo(string uri, string outputDirectory)
    {
      var video = GetVideoFromSingleVideo(uri);

      var downloader = new Downloader(this);
      downloader.AsVideo(outputDirectory, new System.Collections.Generic.List<YoutubeVideo> { video });
    }
    private void downloadPlaylistAsVideo(string uri, string outputDirectory)
    {
      var videos = GetListOfVideosFromPlaylist(uri);

      var downloader = new Downloader(this);
      downloader.AsVideo(outputDirectory, videos);
    }