混合视频类型内容在iPhone上的AVQueuePlayer中排队

我想开始为这篇荒谬的长篇文章道歉，但我试图提供尽可能多的代码和数据供你参考 .

我正在开发一个视频项目，我需要AVQueuePlayer的灵活性（最重要的是能够自由地缩放和布局视频层，以及创建我的自定义控件） . 问题是，我需要能够混合不同类型的视频内容（在这种情况下是渐进式下载.mp4和http流式传输.m3u8） . 这是事情变得时髦的地方 .

首先是一些代码让你前进：

- (void)viewDidLoad {
   [super viewDidLoad];

   NSArray *assetsArray = [NSArray arrayWithObjects:
                        [AVPlayerItem playerItemWithURL: [NSURL URLWithString: kTestPrerollURL]], // .mp4-file on server
                        [AVPlayerItem playerItemWithURL: [NSURL URLWithString: kTestVideoURL]],   // .m3u8-file on server
                        [AVPlayerItem playerItemWithURL: [NSURL fileURLWithPath: [[NSBundle mainBundle] pathForResource: @"2" ofType:@"m4v"]]], // local m4v-file
                        [AVPlayerItem playerItemWithURL: [NSURL fileURLWithPath: [[NSBundle mainBundle] pathForResource: @"3" ofType:@"m4v"]]], // local m4v-file
                        nil];

    // Add KVO observation on each player item to track when they are ready for playback
    for(id playerItem in assetsArray) {
       [playerItem addObserver: self forKeyPath:@"status" options: 0 context: NULL];
    }

    [self setPlayer: [AVQueuePlayer queuePlayerWithItems: assetsArray]];


    [self setPlayerLayer: [AVPlayerLayer playerLayerWithPlayer: [self player]]];
    [[self playerLayer] setFrame: [playerView bounds]];
    // Additional layer customization...
    [[playerView layer] addSublayer: [self playerLayer]];
    [playerView setBackgroundColor: [UIColor clearColor]];

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

当AVPlayerItem更改状态时，将调用此方法：

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

   // A bunch of loggers...
   if([(AVPlayerItem *)object status] == AVPlayerItemStatusReadyToPlay) {
      CGSize   movieSize = [[[player currentItem] asset] naturalSize];
      CGRect   playerRect = [playerView frame];
      playerRect.size.height  = playerRect.size.width * movieSize.height/movieSize.width + 7.0;
      [playerView  setFrame: playerRect];
      [playerLayer setFrame: [playerView bounds]];

      [player play];
   }
}

如果用户选择按“下一步”按钮，则播放器会跳到下一个剪辑：

- (IBAction)next:(id)sender {
   NSLog(@"------ USER SWITCHED TO NEXT ------");
   AVPlayerItem *object = (AVPlayerItem *)[player currentItem];
   [object removeObserver:self forKeyPath: @"status"];
   [player advanceToNextItem];
}

最后，当AVPlayerItem到达结尾时，调用此方法：

- (void)playerItemDidReachEnd:(NSNotification *)notification {
   NSLog(@"------ PLAYER ITEM DID REACH END ------");
   AVPlayerItem *object = (AVPlayerItem *)[notification object];
   [object removeObserver:self forKeyPath: @"status"];
}

好的，所以我的问题是混合不同的格式（在这种情况下是m3u8文件）会导致一些时髦的行为 .

如果我首先在队列中加载m3u8文件，它会正常播放，但如果我使用advanceToNextItem，则应用程序崩溃 . NSZombieEnabled报道：

*** -[Not A Type retain]: message sent to deallocated instance 0x684dfe0
[Switching to process 67957]

调用堆栈显示了我的边界释放（MyPlayer是项目的名称）：

po [NSThread callStackSymbols]
2011-01-05 16:12:57.151 MyPlayer[67957:6303] *** __NSAutoreleaseNoPool(): Object 0x56a0580 of class _NSCallStackArray autoreleased with no pool in place - just leaking
<_NSCallStackArray 0x56a0580>(
0   MyPlayer                            0x00002154 start + 0,
1   CoreFoundation                      0x00e72f22 _CF_forwarding_prep_0 + 50,
2   CoreFoundation                      0x00e140bc CFRetain + 92,
3   CFNetwork                           0x014c436e _ZN21XConnectionEventQueueI12XLoaderEvent18XLoaderEventParamsE10pushEventsEP20XConnectionEventInfoIS0_S1_El + 120,
4   CFNetwork                           0x014c4252 _ZN19URLConnectionLoader16pushEventsLockedEP20XConnectionEventInfoI12XLoaderEvent18XLoaderEventParamsEl + 120,
5   CFNetwork                           0x014c41c7 _ZN19URLConnectionLoader10pushEventsEP20XConnectionEventInfoI12XLoaderEvent18XLoaderEventParamsEl + 57,
6   CFNetwork                           0x015976b6 _ZN19URLConnectionClient25getRequestForTransmissionEhP14_CFURLResponsePK13_CFURLRequestPP9__CFError + 942,
7   CFNetwork                           0x014c3030 _ZN19URLConnectionClient22_clientWillSendRequestEPK13_CFURLRequestP14_CFURLResponsePNS_26ClientConnectionEventQueueE + 230,
8   CFNetwork                           0x01597789 _ZN19URLConnectionClient26ClientConnectionEventQueue33processAllEventsAndConsumePayloadEP20XConnectionEventInfoI12XClientEvent18XClientEventParamsEl + 141,
9   CFNetwork                           0x014c2e3c _ZN19URLConnectionClient13processEventsEv + 100,
10  CFNetwork                           0x014c2cb7 _ZN17MultiplexerSource7performEv + 251,
11  CoreFoundation                      0x00ee301f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15,
12  CoreFoundation                      0x00e4128b __CFRunLoopDoSources0 + 571,
13  CoreFoundation                      0x00e40786 __CFRunLoopRun + 470,
14  CoreFoundation                      0x00e40240 CFRunLoopRunSpecific + 208,
15  CoreFoundation                      0x00e43504 CFRunLoopRun + 84,
16  CoreMedia                           0x00cb39af FigThreadGlobalNetworkBufferingRunloop + 149,
17  CoreMedia                           0x00cb624a figThreadMain + 308,
18  libSystem.B.dylib                   0x9473885d _pthread_start + 345,
19  libSystem.B.dylib                   0x947386e2 thread_start + 34
)

如果.m3u8文件放在队列中第一个位置之后的某个位置，我得到状态AVPlayerItemStatusFailed，并且剪辑跳到队列中的下一个剪辑 .

我意识到这可能与某些内存管理有关，但与此同时我开始怀疑它 . 但是，很明显我做错了，所以每个解决方案的建议都非常受欢迎 .