如何從AVPlayer獲取音頻流狀態的通知？

Question

我正在使用AVPlayer來傳輸一些實時HTTP音頻，而不是AVAudioPlayer，它不支持實時HTTP音頻流，問題是，我如何獲得當前播放的狀態？ 例如：

點擊播放按鈕 - > [加載] - > [播放]點擊暫停按鈕 - > [已暫停]

我需要在加載時顯示微調器，在播放時顯示暫停按鈕並在暫停時顯示播放按鈕，我知道我可以觀察AVPlayer的“狀態”和“速率”屬性：

rate：當前的播放速度。 0.0表示“已停止”，1.0表示“以當前項目的自然速率進行游戲”。

status：表示播放器是否可用於播放。

AVPlayerStatusUnknown,
AVPlayerStatusReadyToPlay,
AVPlayerStatusFailed

因此無法指示音頻是“正在加載”，並且在狀態更改為AVPlayerStatusReadyToPlay后，仍然需要一些時間來播放音頻（可能因為它是實時音頻）。

但無論如何，我如何獲得當前播放的正確狀態？ 我知道Matt有一個AudioStream，但它不支持HTTP Live音頻。

非常感謝！

Answer 1

我用了

    [self.mPlayerItem addObserver:self 
                   forKeyPath:kStatusKey 
                      options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                      context:AVPlayerDemoPlaybackViewControllerStatusObservationContext];

監控狀態鍵（“狀態”）。 然后我創建了播放器

[self setPlayer:[AVPlayer playerWithPlayerItem:self.mPlayerItem]];  

並在observeValueForKeyPath中

    if (context == AVPlayerDemoPlaybackViewControllerStatusObservationContext)
{        
    AVPlayerStatus status = [[change objectForKey:NSKeyValueChangeNewKey] integerValue];
    switch (status)
    {
            /* Indicates that the status of the player is not yet known because 
             it has not tried to load new media resources for playback */
        case AVPlayerStatusUnknown:
        {
            [lblvalidation setText:@"Loading..."];

            NSLog(@"AVPlayerStatusUnknown");
        }
            break;

        case AVPlayerStatusReadyToPlay:
        {
            /* Once the AVPlayerItem becomes ready to play, i.e. 
             [playerItem status] == AVPlayerItemStatusReadyToPlay,
             its duration can be fetched from the item. */

            NSLog(@"AVPlayerStatusReadyToPlay");

            [self.player play];
            [lblvalidation setText:@"Playing..."];
        }
            break;

        case AVPlayerStatusFailed:
        {
            [lblvalidation setText:@"Error..."];
            NSLog(@"AVPlayerStatusFailed");
        }
            break;
    }
}

這適合我...我希望它對你有所幫助。

Answer 2

針對Swift 2進行了更新：

 private var AVPlayerDemoPlaybackViewControllerStatusObservationContext = 0

添加觀察者：

player.currentItem!.addObserver(self, forKeyPath: "status", options: NSKeyValueObservingOptions.New, context: &AVPlayerDemoPlaybackViewControllerStatusObservationContext)

觀察

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {

    if context == &AVPlayerDemoPlaybackViewControllerStatusObservationContext {
        if let change = change as? [String: Int]
        {
            let status = change[NSKeyValueChangeNewKey]!

            switch status {
            case AVPlayerStatus.Unknown.rawValue:
                print("The status of the player is not yet known because it has not tried to load new media resources for playback")

            case AVPlayerStatus.ReadyToPlay.rawValue:
                self.playButtonPressed(playButton)
                print("The player is Ready to Play")

            case AVPlayerStatus.Failed.rawValue:
                print("The player failed to load the video")

            default:
                print("Other status")
            }
        }
    } else {
        super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
    }

}