github "0xced/XCDYouTubeKit" ~> 2.15

AVPlayerViewController *playerViewController = [AVPlayerViewController new];
[self presentViewController:playerViewController animated:YES completion:nil];

__weak AVPlayerViewController *weakPlayerViewController = playerViewController;
[[XCDYouTubeClient defaultClient] getVideoWithIdentifier:videoIdentifier completionHandler:^(XCDYouTubeVideo * _Nullable video, NSError * _Nullable error) {
    if (video)
    {
        NSDictionary *streamURLs = video.streamURLs;
        NSURL *streamURL = streamURLs[XCDYouTubeVideoQualityHTTPLiveStreaming] ?: streamURLs[@(XCDYouTubeVideoQualityHD720)] ?: streamURLs[@(XCDYouTubeVideoQualityMedium360)] ?: streamURLs[@(XCDYouTubeVideoQualitySmall240)];
        weakPlayerViewController.player = [AVPlayer playerWithURL:streamURL];
        [weakPlayerViewController.player play];
    }
    else
    {
        [self dismissViewControllerAnimated:YES completion:nil];
    }
}];

NSString *videoIdentifier = @"9bZkp7q19f0"; // A 11 characters YouTube video identifier
[[XCDYouTubeClient defaultClient] getVideoWithIdentifier:videoIdentifier completionHandler:^(XCDYouTubeVideo *video, NSError *error) {
	if (video)
	{
		// Do something with the `video` object
	}
	else
	{
		// Handle error
	}
}];

- (void) playVideo
{
	XCDYouTubeVideoPlayerViewController *videoPlayerViewController = [[XCDYouTubeVideoPlayerViewController alloc] initWithVideoIdentifier:@"9bZkp7q19f0"];
	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayerPlaybackDidFinish:) name:MPMoviePlayerPlaybackDidFinishNotification object:videoPlayerViewController.moviePlayer];
	[self presentMoviePlayerViewControllerAnimated:videoPlayerViewController];
}

- (void) moviePlayerPlaybackDidFinish:(NSNotification *)notification
{
	[[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:notification.object];
	MPMovieFinishReason finishReason = [notification.userInfo[MPMoviePlayerPlaybackDidFinishReasonUserInfoKey] integerValue];
	if (finishReason == MPMovieFinishReasonPlaybackError)
	{
		NSError *error = notification.userInfo[XCDMoviePlayerPlaybackDidFinishErrorUserInfoKey];
		// Handle error
	}
}

XCDYouTubeVideoPlayerViewController *videoPlayerViewController = [[XCDYouTubeVideoPlayerViewController alloc] initWithVideoIdentifier:@"9bZkp7q19f0"];
[videoPlayerViewController presentInView:self.videoContainerView];
[videoPlayerViewController.moviePlayer play];