使用 AVPlayer 处理流事件

Question

我正在构建一个播放音频流的应用程序（来自网络广播）。

我正在使用AVPlayer 。

1. 我想知道当连接速度较慢或用户只是单击“播放”时，您将如何处理AVPlayer's “缓冲”。 我想检测AVPlayer正在“缓冲”以显示UIActivityIndicatorView 。

2. 在后台运行时同样的问题。 如果在这种情况下进行缓冲，我该怎么办？

Answer 1

对于第一个问题

你可以参考我关于这个主题的回答ios avplayer trigger streaming is out of buffer

对于第二

这是我解决同样问题的方法：

在处理缓冲区空事件的地方添加以下代码：

    if (object == playerItem && [keyPath isEqualToString:@"playbackBufferEmpty"])
    {
        if (playerItem.playbackBufferEmpty) {
            [[NSNotificationCenter defaultCenter] postNotificationName:@"message" object:@"Buffering..."];
            
            if([[UIApplication sharedApplication] applicationState] == UIApplicationStateBackground)
            {
                task = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^(void) {
                }];
            }
        }
    }

现在，您必须在缓冲区准备好再次运行后停止此后台任务：

if (object == playerItem && [keyPath isEqualToString:@"playbackLikelyToKeepUp"])
{
    if (playerItem.playbackLikelyToKeepUp)
    {
        [player play];
        
        if([[UIApplication sharedApplication] applicationState] == UIApplicationStateBackground)
        {
            [[UIApplication sharedApplication] endBackgroundTask:task];
            task = 0;
        }
    }
}

ps：任务在我的 .h 文件中声明为UIBackgroundTaskIdentifier task;

Answer 2

我已经找到了解决这个问题的方法。

if (self.avPlayer.currentItem.playbackLikelyToKeepUp == NO) 
{
    // Show activity indicator
}

Answer 3

对于 Swift 3

这对我来说很好用，也许它可以帮助，在addPeriodicTimeObserver调用self?.bufferState()

    private func bufferState() {
    if let currentItem = self.avPlayer.currentItem {
        if currentItem.status == AVPlayerItemStatus.readyToPlay {
            if currentItem.isPlaybackLikelyToKeepUp {
                print("Playing ")
            } else if currentItem.isPlaybackBufferEmpty {
                print("Buffer empty - show loader")
            }  else if currentItem.isPlaybackBufferFull {
                print("Buffer full - hide loader")
            } else {
                print("Buffering ")
            }
        } else if currentItem.status == AVPlayerItemStatus.failed {
            print("Failed ")
        } else if currentItem.status == AVPlayerItemStatus.unknown {
            print("Unknown ")
        }
    } else {
        print("avPlayer.currentItem is nil")
    }
}

Answer 4

尝试这个：

AVPlayerItem* mPlayerItem;

---

if(context == AVPlayerDemoPlaybackViewControllerCurrentItemBufferEmptyContext) 
{
    if (object == self.mPlayerItem && [path isEqualToString:@"playbackBufferEmpty"]) 
    {
        if (self.mPlayerItem.playbackBufferEmpty)
        {
            playBufferEmpty = TRUE;
            [indicator startAnimating];
            [vidStreaminglabel setText:@"Buffering..."];
            [vidStreaminglabel setHidden:NO];
        }
    }
}

else if(context == AVPlayerDemoPlaybackViewControllerCurrentItemPlayBackBufferFullContext)
{
    if (object == mPlayerItem && [path isEqualToString:@"playbackBufferFull"]){
        if (self.mPlayerItem.playbackBufferFull) {
            [mPlayer play];
        }
    }
}

else if (context == AVPlayerDemoPlaybackViewControllerCurrentItemPlayBackLikelyToKeepUpContext)
{
    if (object == mPlayerItem && [path isEqualToString:@"playbackLikelyToKeepUp"])
    {
         if(self.mPlayerItem.playbackLikelyToKeepUp)
         {
             // Autoplay after buffer 
             if(!(mRestoreAfterScrubbingRate != 0.f || [self.mPlayer rate] != 0.f))
             {
                 if (self.presentingViewController) {
                     [mPlayer play];
                 }

                 playBufferEmpty = FALSE;
                 [indicator stopAnimating];
                 [vidStreaminglabel setHidden:YES];
             }
        }
    }
}