AVPlayer SeekToTime导致AVLayer消失

Question

我目前正在使用AVAssetWriter来捕获我的视频和数据。完成后，我播放我的AVPlayerItem。问题是在第一次初始播放之后，一旦调用了DidItemFinishPlaying通知，我会尝试将其重新开始。当我这样做时，avlayer消失，而不是显示处于暂停状态的海报帧。我尝试的另一件事是当我即将开始重播视频时正在做SeektoTime但是我可以在我的相机开始播放视频之前看到我的相机大约1-2秒的实时预览。这是我的代码。

let outputFileURL = NSURL(fileURLWithPath: self.outputVidFilePath)

appDel.currCamData = NSFileManager.defaultManager().contentsAtPath(outputFileURL.path!)
appDel.currCamDataType = "Video"
appDel.currCamDataURL = outputFileURL

self.vidPlayer.replaceCurrentItemWithPlayerItem(AVPlayerItem(URL: outputFileURL))

self.avLayer.hidden = false

self.playerTimer = NSTimer.scheduledTimerWithTimeInterval(0.25, target: self, selector: #selector(CameraViewController.checkPlayerStatus), userInfo: nil, repeats: true)

func checkPlayerStatus()
{
    if playerTimer == nil
    {
        return
    }

    if vidPlayer.status == AVPlayerStatus.ReadyToPlay
    {
        if vidPlayer.currentItem != nil
        {
            let currentPlayItem = vidPlayer.currentItem!
            if currentPlayItem.status == AVPlayerItemStatus.ReadyToPlay
            {
                playerTimer!.invalidate()
                playerTimer = nil

                if (!playerNotificationStarted) {

                    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(CameraViewController.itemDidFinishPlaying(_:)), name: AVPlayerItemDidPlayToEndTimeNotification, object: nil)

                    playerNotificationStarted = true

                    vidPlayer.play()
                    isVideoPlaying = true
                }
            }
        }
    }
}

func itemDidFinishPlaying(notification :NSNotification)
{
    self.vidPlayer.seekToTime(kCMTimeZero)

    self.playButton.hidden = false
    self.isVideoPlaying = false
}