title: iOS 5 an instance of AVPlayerItem was deallocated
body: <p>When I try to play a video from my iPhone (located in the documentsDirectory), I get the following error using iOS 5 while it was working fine with iOS 4.3:</p>
  
  <p>An instance 0x168da0 of class AVPlayerItem was deallocated while key value observers were still registered with it. Observation info was leaked, and may even become mistakenly attached to some other object. Set a breakpoint on NSKVODeallocateBreak to stop here in the debugger. Here's the current observation info:
   (
   Context: 0x0, Property: 0x10b570>
   Context: 0x0, Property: 0x117ab0></p>
  
  <p>Here is the code extract:</p>
  
  <pre><code>MPMoviePlayerController *moviePlayerController = [[MPMoviePlayerController alloc] initWithContentURL:[appDelegate.mediaManager loadVideo:[element valueForAttributeNamed:@"value"]]];  
  
          //create a NSNotificationCenter which call moviePlaybackComplete function when video playback finished
          [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlaybackComplete:) name:MPMoviePlayerPlaybackDidFinishNotification object:moviePlayerController];  
  
          //display the moviePlayer view
          [self.view addSubview:moviePlayerController.view];
          moviePlayerController.fullscreen = YES;  
          [moviePlayerController play];
  </code></pre>