seekToTime混淆了两个AVPlayers的同时播放

以下问题 . 我有两个AVPlayers，每个都用不同的AVPlayerItem初始化 . 成功加载AVPlayerItem后，我将AVPlayerLayer添加到视图层 . 正如您在下面的代码中看到的那样 .

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.playerItem = [[AVPlayerItem alloc] initWithURL:[self.video getVideoPath]];
    [self.playerItem addObserver:self forKeyPath:@"status" options:0 context:nil];
    [self.playerItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:0 context:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(videoEnded)
                                             name:AVPlayerItemDidPlayToEndTimeNotification
                                           object:nil];


    self.player = [[AVPlayer alloc] initWithPlayerItem:playerItem];

    self.overlayPlayerItem = [[AVPlayerItem alloc] initWithURL:[self.compareVideo getVideoPath]];

    [self.overlayPlayerItem addObserver:self forKeyPath:@"status" options:0 context:nil];
    [self.overlayPlayerItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:0 context:nil];

    if (self.overlayPlayer==nil) {
        self.overlayPlayer = [[AVPlayer alloc] initWithPlayerItem:self.overlayPlayerItem];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([object isKindOfClass:[AVPlayerItem class]])
    {
        AVPlayerItem *item = (AVPlayerItem *)object;
        //playerItem status value changed?
    if ([keyPath isEqualToString:@"status"])
    {   //yes->check it...
        switch(item.status)
        {
            case AVPlayerItemStatusFailed:
                NSLog(@"player item status failed");
                break;
            case AVPlayerItemStatusReadyToPlay:
            {
                NSLog(@"player item status is ready to play");
                if (item == self.playerItem && !videoLayerAdded) {
                    videoLayerAdded = YES;
                    AVPlayerLayer* layer = [AVPlayerLayer playerLayerWithPlayer:player];
                    layer.frame = self.videoContainer.bounds;
                    [self.videoContainer.layer insertSublayer:layer atIndex:0];
                } else if (item == self.overlayPlayerItem && !overlayLayerAdded){
                    overlayLayerAdded = YES;
                    AVPlayerLayer* layer = [AVPlayerLayer playerLayerWithPlayer:overlayPlayer];
                    layer.frame = self.videoOverlayContainer.bounds;
                    [self.videoOverlayContainer.layer insertSublayer:layer atIndex:0];
                }
                break;
            }
            case AVPlayerItemStatusUnknown:
                NSLog(@"player item status is unknown");
                break;
        }
    }
    else if ([keyPath isEqualToString:@"playbackBufferEmpty"])
    {
        if (item.playbackBufferEmpty)
        {
            NSLog(@"player item playback buffer is empty");
        }
    }
}
}

当我点击播放按钮时，视频会播放 . 如果我再次击中它们就停止了，到目前为止一切顺利 .

- (IBAction)playButtonClicked:(id)sender{

    //is playing
    if(self.player.rate>0.0 || self.overlayPlayer.rate>0.0){
        [self.player pause];
        [self.overlayPlayer pause];
    } else {
        [self.player play];
        [self.overlayPlayer play];
    }
}

我有两个UISlider，允许我在每个视频中前进和后退 . 我使用seekToTime跳转到视频中的某个时间 .

- (IBAction)sliderChanged:(id)sender{
    UISlider *slider = (UISlider *)sender;

    //stop any video when using the slider
    if(self.player.rate>0.0){
            [self.player pause];
    }
    if(self.overlayPlayer.rate>0.0){
        [self.overlayPlayer pause];
    }

    if (slider.tag == 1) {
        double time = (self.playerTimeSlider.value * CMTimeGetSeconds(self.player.currentItem.asset.duration));
        [self.player seekToTime:CMTimeMakeWithSeconds(time, NSEC_PER_SEC) toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];
    } else if (slider.tag == 2){
        double time = (self.overlayTimeSlider.value * CMTimeGetSeconds(self.overlayPlayer.currentItem.asset.duration));
        [self.overlayPlayer seekToTime:CMTimeMakeWithSeconds(time, NSEC_PER_SEC) toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];
    }
}

视频也可以有不同的长度 . 但是，如果视频结束，我会将其设置为开头，同时使用seekToTime .

我的问题是我最初可以播放两个视频 . 我可以毫无问题地暂停和恢复它们 . 但是一旦我暂停并使用seekToTime进行任何视频和恢复，或者如果视频结束，我使用seekToTime重置它们并再次点击播放我的状态观察者为两个PlayerItem激活AVPlayerItemStatusFailed .

然后这些项目的持续时间变为0.我检查过，PlayerItems不是零 .

我没有崩溃，但我不能再播放视频了 . 当我只使用一个播放器时，我可以使用seekToTime跳过它，并在视频结尾处重置它而没有问题 .

我通过论坛阅读，人们说你显然可以使用多达4个AVPlayers，所以我想我应该用2保存 . 我还读到其他应用程序可以用尽视频渲染管道，但我确保我没有我的iPad上有后台任何其他应用程序 .

任何帮助，为什么这不适合我，甚至更好，一个修复，非常感谢 .

Update: 我实际上是从AVPlayerItem对象中记录了错误：

error: Error Domain=AVFoundationErrorDomain Code=-11819 "Cannot Complete Action"  
UserInfo=0x19e370 {NSLocalizedRecoverySuggestion=Try again later., 
NSLocalizedDescription=Cannot Complete Action}

代码-11819代表AVErrorMediaServicesWereReset . 这有助于任何人帮助我吗？