AVPlayer Content Modes

I have a AVPlayer, and am using it as a background in my UIView as an aesthetic. To initialize and instantiate it, I do

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    guard let path = Bundle.main.path(forResource: "Background", ofType:"mp4") else {
        debugPrint("Background.mp4 not found")
        return
    }

    let player = AVPlayer(url: URL(fileURLWithPath: path))
    let playerLayer = AVPlayerLayer(player: player)

    playerLayer.frame = self.view.bounds
    player.actionAtItemEnd = .none
    player.volume = 0.0

    //chage content mode ** TODO **

    self.view.layer.addSublayer(playerLayer)
    player.play()

}

When I run this, the video plays just as expected, however the AVPlayer sets the content mode to fitToWidth as a default. I searched through all the methods of player and playerLayer for some type of method on changing content type, but to no avail.

What I want is instead of fitToWidth I would like fitToHeight.

Any thoughts? Thanks for looking!