关于ios：录制后临时目录中的AVPlayer视频几秒钟后停止播放

AVPlayer video from temporary directory after recording stops playing after few seconds

我有一个定制的相机，可以录制视频和拍照。问题是在录制并推送带有录制视频预览的 viewController 后，视频在几秒钟后停止播放。
所以流程是：

Custom camera opened;

I've recorded a video;

Controller with recorded video preview is shown. (by pushViewController(controller, animated: true));

Video started playing;

After N seconds (1-2 sec) video stopped for some reason.

代码：

didFinishRecordingTo outputFileURL:

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if let error = error {
// handle error
return
}

if let currentBackgroundRecordingID = backgroundRecordingID {
backgroundRecordingID = UIBackgroundTaskIdentifier.invalid

if currentBackgroundRecordingID != UIBackgroundTaskIdentifier.invalid {
UIApplication.shared.endBackgroundTask(currentBackgroundRecordingID)
}
}
// open viewController and play recently recorded video from temporary files.

setupVideoBackground() -> AVPlayer 的配置，在 viewDidLoad/viewWillAppear 中调用：

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let player = AVPlayer(url: url)
player.actionAtItemEnd = .none

let playerLayer = AVPlayerLayer(player: player)
playerLayer.frame = self.view.frame
playerLayer.videoGravity = .resizeAspectFill

self.view.layer.insertSublayer(playerLayer, at: 0)

player.seek(to: .zero)
player.play()

推送视图控制器：

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let vc = TestController()
vc.url = url!
self.navigationController?.pushViewController(vc, animated: true)

注意：一件奇怪的事情是，如果我将 pushViewController 与动画：false 一起使用，那么播放器将播放完整视频，如果动画：true，视频将在几秒钟后停止。此外，当前视图控制器工作正常。

注意 2：如果我使用 DispatchQueue 以 0.5 秒的延迟调用 setupVideoBackground()，视频将不会停止。

我不明白，为什么视频在 pushViewController(vc, animated: false) 之后播放正常，而在 pushViewController(vc, animated: true)

之后停止播放