在AVPlayerViewControllerDelegate中添加方法，当进入画中画模式或从画中画模式退出时，都需要设置AVPlayerViewController的contentOverlayView为nil，并在从画中画模式退出时调用AVPlayerViewController的方法viewWillDisappear()和viewDidDisappear()。

示例代码如下：

extension ViewController: AVPlayerViewControllerDelegate {
    
    func playerViewController(_ playerViewController: AVPlayerViewController, willBeginPictureInPictureWithAnimationCoordinator animationCoordinator: AVPictureInPictureControllerAnimationCoordinator) {
        playerViewController.contentOverlayView?.removeFromSuperview()
        playerViewController.contentOverlayView = nil
    }
    
    func playerViewController(_ playerViewController: AVPlayerViewController, willEndPictureInPictureWithAnimationCoordinator animationCoordinator: AVPictureInPictureControllerAnimationCoordinator) {
        playerViewController.viewWillDisappear(false)
        playerViewController.viewDidDisappear(false)
        playerViewController.contentOverlayView?.removeFromSuperview()
        playerViewController.contentOverlayView = nil
    }
    
}