swift – 在iOS 11上滑动时AVPlayerViewController黑屏

我正在使用AVPlayerViewController在iPad-App上播放视频文件(H.264,AAC,MP4-Container).
一切都在iOS 10中运行.而且在iOS 11中它正确播放视频.

但是在iOS 11中,当我开始向任何方向滑动时,它会立即使视频变黑并且还会使音频静音.它还会在底部的时间轴旁边显示一个加载指示器.

它也忽略了allowsPictureInPicturePlayback属性,因此它不会在iOS 11上显示PIP-Button.

这是我使用的代码：

avPlayerController = AVPlayerViewController()
avPlayerController?.showsPlaybackControls = true
avPlayerController?.allowsPictureInPicturePlayback = true
avPlayerController?.player = AVPlayer(url: videoUrl as URL)
avPlayerController?.player?.play()            

self.present(self.avPlayerController!,animated: true,completion: nil)            

avPlayerController?.player?.actionAtItemEnd = AVPlayerActionAtItemEnd.none
NotificationCenter.default.addobserver(self,selector: #selector(onVideoCompleted),name: NSNotification.Name.AVPlayerItemDidplayToEndTime,object: self.avPlayerController!.player?.currentItem)

此功能可在视频结束时关闭视频播放器：

func onVideoCompleted(notification:Notification) {
    self.avPlayerController?.player = nil
    self.avPlayerController?.dismiss(animated: true,completion: nil)
}

当屏幕黑屏时,我在控制台中看到了这个：

AVOutputDevicediscoverySession (figRoutediscoverer) 
>>>> -[AVfigRoutediscovererOutputDevicediscoverySessionImpl 
outputDevicediscoverySessionDidChangediscoveryMode:]: Setting device discovery 
mode to discoveryMode_Presence (client: MyAppName)

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

    if avPlayerController?.isBeingdismissed ?? false {
        avPlayerController?.player = nil
    }
}