// init downloader
YoutubeDownloader downloader = new YoutubeDownloader();

// you can easly implement or extend default parsing logic 
YoutubeDownloader downloader = new YoutubeDownloader(new Parser()); 
// or just extend functionality via existing API
// cipher features
downloader.addCipherFunctionPattern(2, "\\b([a-zA-Z0-9$]{2})\\s*=\\s*function\\(\\s*a\\s*\\)\\s*\\{\\s*a\\s*=\\s*a\\.split\\(\\s*\"\"\\s*\\)");
downloader.addCipherFunctionEquivalent("some regex for js function", new CustomJavaFunction());
// extractor features
downloader.setParserRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36");
downloader.setParserRetryOnFailure(1);

// parsing data
String videoId = "abc12345"; // for url https://www.youtube.com/watch?v=abc12345
YoutubeVideo video = downloader.getVideo(videoId);

// video details
VideoDetails details = video.details();
System.out.println(details.title());
...
System.out.println(details.viewCount());
details.thumbnails().forEach(image -> System.out.println("Thumbnail: " + image));

// get videos with audio
List<AudioVideoFormat> videoWithAudioFormats = video.videoWithAudioFormats();
videoWithAudioFormats.forEach(it -> {
    System.out.println(it.videoQuality() + " : " + it.url());
});

// filtering only video formats
List<VideoFormat> videoFormats = video.findVideoWithQuality(VideoQuality.hd720);
videoFormats.forEach(it -> {
    System.out.println(it.videoQuality() + " : " + it.url());
});

// itags can be found here - https://gist.github.com/sidneys/7095afe4da4ae58694d128b1034e01e2
Format formatByItag = video.findFormatByItag(136); 
if (formatByItag != null) {
    System.out.println(formatByItag.url());
}

File outputDir = new File("my_videos");

// sync downloading
File file = video.download(videoFormats.get(0), outputDir);

// async downloading with callback
video.downloadAsync(videoFormats.get(0), outputDir, new OnYoutubeDownloadListener() {
    @Override
    public void onDownloading(int progress) {
        System.out.printf("Downloaded %d%%\n", progress);
    }
            
    @Override
    public void onFinished(File file) {
        System.out.println("Finished file: " + file);
    }

    @Override
    public void onError(Throwable throwable) {
        System.out.println("Error: " + throwable.getLocalizedMessage());
    }
});

// async downloading with future
Future<File> future = video.downloadAsync(format, outputDir);
File file = future.get(5, TimeUnit.SECONDS);