Question

在我的项目中，我使用Kolada视图(here)来展示一堆卡片，每张卡片上都有一个视频。有时当我加载下一个视频时，我的AVPlayer无法播放视频，它只显示第一帧并被冻结。我正在使用几个观察者来跟踪视频实际播放的时间，如果它可能跟上播放的话。如果没有正确释放，观察者会导致播放冻结吗？如果没有，还有什么导致AVPlayer的播放冻结？

更新：我注意到playbackLikelyToKeepUp有时从未被调用过，当发生这种情况时，即使我更改了播放器项，AVPlayer也不会再次调用它。因此视频播放永远不会恢复。

 init(frame: CGRect, mediaURL: NSURL, thumbURL: NSURL?, isLoop: Bool) {
    self.mediaURL = mediaURL
    self.isLoop = isLoop

    let asset = AVAsset(URL: mediaURL)
    let item = AVPlayerItem(asset: asset)
    player = AVPlayer(playerItem: item)
    player!.actionAtItemEnd = .None

    super.init(frame: frame)

    asset.loadValuesAsynchronouslyForKeys(["duration"], completionHandler: { () -> Void in
        var error: NSError?
        let keyStatus: AVKeyValueStatus = asset.statusOfValueForKey("duration", error: &error)
        switch (keyStatus) {

        case .Loaded:
            let duration: CMTime = asset.duration
            self.currentDuration = duration
            self.delegate?.updateDuration()
        default:
            break
        }

    })

    NSNotificationCenter.defaultCenter().addObserver(
        self,
        selector: #selector(MediaPlayerView.playerItemDidReachEnd(_:)),
        name: AVPlayerItemDidPlayToEndTimeNotification,
        object: player!.currentItem)

    self.timeObserver = self.player!.addPeriodicTimeObserverForInterval(CMTimeMakeWithSeconds(1.0 / 30.0, Int32(NSEC_PER_SEC)), queue: nil, usingBlock: {
        [weak self] (time) -> Void in

        if time.value > 0 {
            self?.spinnerView?.stopAnimating()
            if(self?.player != nil){
                if(self?.player!.rate > 0){
                    self?.placeholderImageView?.hidden = true
                }
            }

            let timeInSeconds = CMTimeGetSeconds(time)
            self?.delegate?.playbackReachedTime(timeInSeconds)

        }
    })

    player!.currentItem?.addObserver(self, forKeyPath: playbackLikelyToKeepUp, options: .New, context: &observationContext)
    player!.addObserver(self, forKeyPath: "rate", options: .New, context: &observationContext)

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(MediaPlayerView.playerIsTapped(_:)))
    addGestureRecognizer(tapGesture)
}

Answer 1

在AVPlayer对象的现有实例上使用replaceCurrentItemWithPlayerItem，将值设置为nil以销毁它。

AVPlayer没有播放

1 个答案: