MPMoviePlayerController在模拟器中工作，但不在设备上

Question

我有一个流式传输视频的MPMoviePlayerController。问题是视频和音频在模拟器中工作正常，但在设备上，视图只是变黑，没有音频或视频出现。这是我的代码：

- (IBAction)playVideoPress:(id)sender
{
    MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL:mediaURL];

    _mpPlayer3 = player;

    [[NSNotificationCenter defaultCenter]
         addObserver:self
         selector:@selector(moviePlayerDidFinish:)
         name:MPMoviePlayerPlaybackDidFinishNotification
         object:nil];

    _mpPlayer3.controlStyle = MPMovieControlStyleDefault;
    [_playerView3 addSubview: _mpPlayer3.view];
    [_mpPlayer3.view setFrame:_playerView3.bounds];

    [_mpPlayer3 play];
}

然后视频结束时的通知是：

- (void)moviePlayerDidFinish:(NSNotification*)notification {
    [[NSNotificationCenter defaultCenter]
     removeObserver:self
     name:MPMoviePlayerPlaybackDidFinishNotification
     object:nil];

    NSLog(@"Did Finish Notification");

    [_mpPlayer3 stop];

    _mpPlayer3 = nil;
}

这在模拟器中运行良好，但只是在视图中显示我要显示视频的黑屏。发生的另一个奇怪的事情是，当我在模拟器中运行它时，我得到一堆错误，如为：

Error loading /System/Library/Extensions/AudioIPCDriver.kext/Contents/Resources/AudioIPCPlugIn.bundle/Contents/MacOS/AudioIPCPlugIn:  dlopen(/System/Library/Extensions/AudioIPCDriver.kext/Contents/Resources/AudioIPCPlugIn.bundle/Contents/MacOS/AudioIPCPlugIn, 262): Symbol not found: ___CFObjCIsCollectable

我不知道这与播放视频的模拟器和设备有什么关系，但我想我会在这里提一下。