title: MPMoviePlayerViewController dismisses immediately
body: <p>I am playing a movie via:</p>
  
  <pre><code>moviePlayer = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL fileURLWithPath:asset.filepath]];
  
  //[[vc moviePlayer] prepareToPlay];
  [self presentViewController:moviePlayer animated:YES completion:NULL];
  </code></pre>
  
  <p>The controller shows up but immediately after, dismisses itself. What am I doing wrong? Thanks!</p>