使用 AVPlayer 處理流事件

Question

我正在構建一個播放音頻流的應用程序（來自網絡廣播）。

我正在使用AVPlayer 。

1. 我想知道當連接速度較慢或用戶只是單擊“播放”時，您將如何處理AVPlayer's “緩沖”。 我想檢測AVPlayer正在“緩沖”以顯示UIActivityIndicatorView 。

2. 在后台運行時同樣的問題。 如果在這種情況下進行緩沖，我該怎么辦？

Answer 1

對於第一個問題

你可以參考我關於這個主題的回答ios avplayer trigger streaming is out of buffer

對於第二

這是我解決同樣問題的方法：

在處理緩沖區空事件的地方添加以下代碼：

    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) {
                }];
            }
        }
    }

現在，您必須在緩沖區准備好再次運行后停止此后台任務：

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

ps：任務在我的 .h 文件中聲明為UIBackgroundTaskIdentifier task;

Answer 2

我已經找到了解決這個問題的方法。

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

Answer 3

對於 Swift 3

這對我來說很好用，也許它可以幫助，在addPeriodicTimeObserver調用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

嘗試這個：

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];
             }
        }
    }
}