Question

如何检测AVPlayer何时正在播放？调用play()函数和实际播放视频之间似乎有一点延迟。

Answer 1

视频：

AVPlayer有一个名为rate (Float)的参数，如果rate大于0.0，则会显示当前播放的视频。

您可以查看rate是否!=0 :(如果玩家倒退，费率可能为负数）

if vidPlayer != nil && vidPlayer.rate != 0 {
  println("playing")
}

AVPlayer class reference

Answer 2

据我所知，我同意你的看法，调用play()功能和实际播放视频之间会有一点延迟（换句话说，视频的第一帧有时间）已被渲染）。延迟取决于一些标准，如视频类型（视频点播或直播），网络条件......但幸运的是，我们能够知道视频的第一帧渲染时，我的意思是视频实际播放的时间

通过观察当前status的{{1}}以及AVPlayerItem时，它应该是已渲染的第一帧。

AVPlayerItemStatusReadyToPlay

顺便说一下，还有另一种解决方案，我们会在[self.playerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:NULL]; -(void)observeValueForKeyPath:(NSString*)path ofObject:(id)object change:(NSDictionary*)change context:(void*) context { if([self.playerItem status] == AVPlayerStatusReadyToPlay){ NSLog(@"The video actually plays") } }处看到readyForDisplay状态，它还会指示视频呈现的时间。但是，该解决方案存在Apple文档中提到的缺点

AVPlayerLayer

以下是示例代码

/*!
     @property      readyForDisplay
     @abstract      Boolean indicating that the first video frame has been made ready for display for the current item of the associated AVPlayer.
     @discusssion   Use this property as an indicator of when best to show or animate-in an AVPlayerLayer into view. 
                    An AVPlayerLayer may be displayed, or made visible, while this propoerty is NO, however the layer will not have any 
                    user-visible content until the value becomes YES. 
                    This property remains NO for an AVPlayer currentItem whose AVAsset contains no enabled video tracks.
 */
@property(nonatomic, readonly, getter=isReadyForDisplay) BOOL readyForDisplay;

但是，self.playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player]; [self.playerLayer addObserver:self forKeyPath:@"readyForDisplay" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:NULL]; -(void)observeValueForKeyPath:(NSString*)path ofObject:(id)object change:(NSDictionary*)change context:(void*) context { if([self.playerLayer isReadyForDisplay]){ NSLog(@"Ready to display"); } }应该返回YES，但是，作为文档，它不能保证。

我希望这会有所帮助。

Answer 3

快捷键4

方法1

var rateObserver: NSKeyValueObservation?

self.rateObserver = myPlayer.observe(\.rate, options:  [.new, .old], changeHandler: { (player, change) in
     if player.rate == 1  {
          print("Playing")
      }else{
           print("Stop")
      }
 })

 // Later You Can Remove Observer      
 self.rateObserver?.invalidate()

方法2

myPlayer.addObserver(self, forKeyPath: "rate", options: NSKeyValueObservingOptions(rawValue: NSKeyValueObservingOptions.new.rawValue | NSKeyValueObservingOptions.old.rawValue), context: nil)

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
      if keyPath == "rate" { 
          if player.rate == 1  {
              print("Playing")
          }else{
               print("Stop")
          }
      }
 }

Answer 4

您可能要检测两件事：

AVPlayerLayer的{{1}}是在接收到第一帧时。
isReadyForDisplay的{{1}}是视频实际开始播放的时间。

要检查这两种状态，可以使用可观察性。

您将在类中定义三个对象：

AVPlayerItem

播放器实现将如下所示：

readyToPlay

这里，上下文是简单的整数或枚举。

您可以通过覆盖var player: AVPlayer? var playerItem: AVPlayerItem? var playerLayer: AVPlayerLayer?方法来处理事件。

guard let videoURL = URL(string: "<videoPath>") else {
   return
}
asset = AVAsset(url: videoURL)
guard let asset = asset else {
   return
}
playerItem = AVPlayerItem(asset: asset, automaticallyLoadedAssetKeys: requiredAssetKeys)
guard let playerItem = playerItem else {
   return
}
playerItem.addObserver(self,
                       forKeyPath: #keyPath(AVPlayerItem.status),
                       options: [.old, .new],
                       context: &playerItemContext)
player = AVPlayer(playerItem: playerItem)
playerLayer = AVPlayerLayer(player: player)
playerLayer?.addObserver(self, 
                         forKeyPath: #keyPath(AVPlayerLayer.isReadyForDisplay), 
                         options: [.old, .new], 
                         context: &playerLayerContext)
avpController.player = player 
avpController.view.frame.size.height = playerView.frame.size.height
avpController.view.frame.size.width = playerView.frame.size.width
playerView.addSubview(avpController.view)
avpController.player?.play()

别忘了删除观察者。

observeValue

检测AVPlayer播放的时间

4 个答案: