Upon screen lock video is paused if it doesn't have any volume

Question

In my app, audio and video play even if the screen is locked, with controls of play and pause displayed on the locked screen. However, I am surprised to observe that when the video doesn't have any volume and I lock the phone, then the video also pauses. Is it possible that MPRemoteCommandCenter recognizes if the video has volume or not, and accordingly it decides to pause the video?

Code snippet -

In my AppDelegate I implemented:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    MPRemoteCommandCenter *rcc = [MPRemoteCommandCenter sharedCommandCenter];
[[rcc skipForwardCommand] setEnabled:NO];
[[rcc skipBackwardCommand] setEnabled:NO];
[[rcc nextTrackCommand] setEnabled:NO];
[[rcc previousTrackCommand] setEnabled:NO];
[[rcc skipForwardCommand] setEnabled:NO];
[[rcc skipBackwardCommand] setEnabled:NO];
rcc.playCommand.enabled = YES;
rcc.pauseCommand.enabled = YES;
[[MPRemoteCommandCenter sharedCommandCenter].playCommand addTarget:self action:@selector(play)];
[[MPRemoteCommandCenter sharedCommandCenter].pauseCommand addTarget:self action:@selector(pause)];
}

- (void) play {
[[MyVideoController instance] play];
}

- (void) pause {
[[MyVideoController instance] pause];
}

in MyVideoController class

AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:nil];
AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:avAsset];
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayback error:nil];
NSError *activationError = nil;
BOOL success = [[AVAudioSession sharedInstance] setActive: YES error: &activationError];

NSMutableDictionary *songInfo = [[NSMutableDictionary alloc] init];

MPMediaItemArtwork *albumArt = [[MPMediaItemArtwork alloc] initWithImage: [UIImage imageNamed:@"Audio_Thumbnail_Play"]];
[songInfo setObject:title forKey:MPMediaItemPropertyTitle];
[songInfo setObject:@"duration" forKey:MPMediaItemPropertyPlaybackDuration];
[songInfo setObject:albumArt forKey:MPMediaItemPropertyArtwork];
[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo];
self.avPlayer = [AVPlayer playerWithPlayerItem:playerItem];
self.avPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:self.avPlayer];

- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:nil];
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionModeDefault error: nil];
}