AVPlayer 항목 버퍼가 비어 있음

Question

스트림 내용을 재생하는 AVPlayer를 사용합니다. 버퍼가 비어있는 시간과 재생할 준비가 된 시간을 알고 싶습니다. 그러나 observer "playbackBufferEmpty"및 "playbackLikelyToKeepUp"은 필요에 따라 매번 작동하지 않습니다. 때로는 효과가 있지만 종종 효과가 없습니다. OSX 10.7.5에서 iPad 시뮬레이터 iOS 6.1 만 사용합니다.

- (void)playAudioStream:(NSURL *)audioStreamURL 
{ 
if(_audioPlayer && _audioPlayer.currentItem) 
{ 
    [_audioPlayer removeObserver:self forKeyPath:StatusKey]; 
    [_audioPlayer.currentItem removeObserver:self forKeyPath:@"playbackBufferEmpty"]; 
    [_audioPlayer.currentItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp"]; 
} 

AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:audioStreamURL]; 

[playerItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil]; 
[playerItem addObserver:self forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil]; 

_audioPlayer = [AVPlayer playerWithPlayerItem:playerItem]; 

[_audioPlayer addObserver:self forKeyPath:StatusKey options:NSKeyValueObservingOptionNew context:nil]; 

//[_audioPlayer replaceCurrentItemWithPlayerItem:playerItem]; 
//_audioPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone; 
[_audioPlayer play]; 
} 
... 

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context 
{ 
if ([keyPath isEqualToString:@"playbackBufferEmpty"]) 
{ 
    if (_audioPlayer.currentItem.playbackBufferEmpty) 
    { 
     ... 
    } 

} 

if ([keyPath isEqualToString:@"playbackLikelyToKeepUp"]) 
{ 
    if (_audioPlayer.currentItem.playbackLikelyToKeepUp) 
    { 
     ... 
    } 
} 
} 

얻을 "빈 버퍼"를 (인터넷 연결이 끊어 때, 예를 들어) 이벤트 "준비를 버퍼링"올바른 방법으로 나를 도와주세요 : 내가 관찰자를 설정하고 듣는 방법은 다음과 이다. 고맙습니다!

Answer 1

옵저버를 추가 할 때 컨텍스트를 사용해야합니다. 다음은 샘플 코드입니다.

초기화 컨텍스트

static void *playbackLikelyToKeepUpKVOToken = &playbackLikelyToKeepUpKVOToken; 
static void *playbackBufferEmpty = &playbackBufferEmpty; 
static void *playbackBufferFull = &playbackBufferFull; 

는

if (context == playbackLikelyToKeepUpKVOToken) 
{ 
    if (self.playerItem.playbackLikelyToKeepUp) 
    { 
     NSLog(@"recieve playbackLikelyToKeepUp"); 
    } 

} 
else if (context == playbackBufferEmpty) 
{ 
    if (self.playerItem.playbackBufferEmpty) 
    { 
     NSLog(@"recieve playbackBufferEmpty"); 
    } 
} 
else if(context == playbackBufferFull) 
{ 
    NSLog(@"recieve playbackBufferFull"); 
} 
else 
{ 
    [super observeValueForKeyPath:path ofObject:object change:change context:context]; 
} 

Answer 2

@Nghia 트란의 대답은 나에게 도움이 관찰자

[self.playerItem removeObserver:self forKeyPath:@"playbackBufferEmpty" context:playbackBufferEmpty]; 
[self.playerItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp" context:playbackLikelyToKeepUpKVOToken]; 
[self.playerItem removeObserver:self forKeyPath:@"playbackBufferFull" context:playbackBufferFull]; 

핸들을 추가합니다. 그는 단지 추가 관측과 혼동/(우리는 모두 필요)

추가 관찰자 관찰자를 제거

[self.playerItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:playbackBufferEmpty]; 
[self.playerItem addObserver:self forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:playbackLikelyToKeepUpKVOToken]; 
[self.playerItem addObserver:self forKeyPath:@"playbackBufferFull" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:playbackBufferFull]; 

제거 관찰자 :

[self.playerItem removeObserver:self forKeyPath:@"playbackBufferEmpty" context:playbackBufferEmpty]; 
[self.playerItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp" context:playbackLikelyToKeepUpKVOToken]; 
[self.playerItem removeObserver:self forKeyPath:@"playbackBufferFull" context:playbackBufferFull];