title: AVAudioSession Won't Play On iOS 7
body: <p>On iOS 6, I have been able to set up an AVAudioSession to play mp3 files.  While running with Base set at iOS 7, this no longer works.  Any ideas why this won't work?  The app never crashes...it just doesn't play the mp3.  I have verified this same code and same URL works on iOS 6 apps.</p>
  
  <p>Errors are:</p>
  
  <pre><code>ERROR:     185: Error creating aggregate audio device: 'what'
  WARNING:   219: The input device is 0x31; 'AppleHDAEngineInput:1B,0,1,0:1'
  WARNING:   223: The output device is 0x28; 'AppleHDAEngineOutput:1B,0,1,1:0'
  ERROR:     398: error 'what'
  _itemFailedToPlayToEnd: {
      kind = 1;
      new = 2;
      old = 0;
  }
  </code></pre>
  
  <p>The code:</p>
  
  <pre><code>- (void)viewDidLoad {
      AVAudioSession *audioSession = [AVAudioSession sharedInstance];
  
      NSError *setCategoryError = nil;
      [audioSession setCategory:AVAudioSessionCategoryPlayback error:&amp;setCategoryError];
  
      if (setCategoryError) { /* handle the error condition */ }
  
      NSError *activationError = nil;    
      [audioSession setActive:YES error:&amp;activationError];
  
      if (activationError) { /* handle the error condition */ }
  
      [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];   
      [self becomeFirstResponder];    
  
      NSURL *newURL = [NSURL URLWithString:_entry.articleUrl];
      self.player = [[MPMoviePlayerController alloc] initWithContentURL: newURL];
      [player prepareToPlay];
      player.allowsAirPlay = YES;
      player.scalingMode = MPMovieScalingModeAspectFit;    
      player.view.frame = self.view.frame;
      [self.view addSubview: player.view];
      [self.player setFullscreen:YES animated:YES];
  
      [[NSNotificationCenter defaultCenter] addObserver:self
                                 selector:@selector(movieFinishedCallback:)
                                     name:MPMoviePlayerPlaybackDidFinishNotification
                                   object:player];
  
      [[NSNotificationCenter defaultCenter] addObserver:self
                                 selector:@selector(exitedFullscreen:) 
                                     name:MPMoviePlayerDidExitFullscreenNotification 
                                   object:player];
  
      [[NSNotificationCenter defaultCenter] addObserver:self 
                                 selector:@selector(playbackStateChanged:) 
                                     name:MPMoviePlayerPlaybackStateDidChangeNotification 
                                   object:player];
      [player play];
  
      [super viewDidLoad];   
  }
  </code></pre>