var player = AVPlayer()
var  playerViewController = AVPlayerViewController()
override func viewDidLoad() {
    super.viewDidLoad()

    do {
        try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: [.mixWithOthers, .allowAirPlay])
        print("Playback OK")
        UIApplication.shared.beginReceivingRemoteControlEvents()
        addPlayerNotifications()
        try AVAudioSession.sharedInstance().setActive(true)
        print("Session is Active")

    } catch {
        fatalError(error.localizedDescription)
    }

}

func addPlayerNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(playerItemDidPlayToEnd), name: .AVPlayerItemDidPlayToEndTime, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(applicationWillEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
}