title: play video in background swift 3
body: <p>hello im trying to play video in background but its give an error and the error is " unexpectedly found nil while unwrapping an Optional value " and im already set the video in Bundle and select copy if need </p>
  
  <p>this the my code </p>
  
  <pre><code>import UIKit
  import AVFoundation
  
  class ViewController: UIViewController {
  
      var avPlayer: AVPlayer!
      var avPlayerLayer: AVPlayerLayer!
      var paused: Bool = false
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          let url = Bundle.main.url(forResource: "Grad_Cap_Toss", withExtension: "mp4")
  
  
          avPlayer = AVPlayer(url: url!)
          avPlayerLayer = AVPlayerLayer(player: avPlayer)
          avPlayerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
          avPlayer.volume = 0
          avPlayer.actionAtItemEnd = AVPlayerActionAtItemEnd.none
  
          avPlayerLayer.frame = view.layer.bounds
          view.backgroundColor = UIColor.clear;
          view.layer.insertSublayer(avPlayerLayer, at: 0)
  
          NotificationCenter.default.addObserver(self,selector: Selector(("playerItemDidReachEnd:")),name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,object: avPlayer.currentItem)
  
      }
  </code></pre>
  
  <p>please any body have ideas for that , thank you </p>