title: AVPlayer layer not showing video content sometimes
body: <p>AVPlayer layer not showing video content sometimes but plays audio.
  This happens some times not each time 
  Here is my lines of code :</p>
  
  <pre><code> override func viewDidLoad() {
          super.viewDidLoad()
          self.tempVideoPath = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("tmpMov.mov")
          self.player = AVPlayer(url: self.tempVideoPath!)
  }
  
   override func viewDidAppear(_ animated: Bool) {
       super.viewDidAppear(animated)
       self.playerLayer = AVPlayerLayer(player: self.player)
       self.playerLayer?.frame = self.videoPlayer.bounds
       self.playerLayer?.backgroundColor = UIColor.yellow.cgColor
       self.videoPlayer.layer.addSublayer(playerLayer!)
       print("player = \(playerLayer?.bounds)")
  
   }
  </code></pre>
  
  <p>Help me to solve this issue.</p>