AddVideoLayerToView.swift

// Load video
// Note: Needs to be a supported AVPlayer format, in this case MP4 (could also be M4V etc.)
if let filePath = Bundle.main.path(forResource: "video", ofType: "mp4") {

    // url
    let fileUrl = URL(fileURLWithPath: filePath)

    // Player
    let player = AVPlayer(url: fileUrl)

    // video layer
    let videoLayer = AVPlayerLayer(player: player)
    videoLayer.frame = self.view.bounds
    videoLayer.videoGravity = AVLayerVideoGravityResizeAspectFill

    let videoView = UIView(frame: self.view.frame)
    videoView.layer.addSublayer(videoLayer)

    // Add video to backgroundView
    self.view.addSubview(videoView)
    self.view.sendSubview(toBack: videoView)

    // play
    player.play()
}