IPhone : AVCaptureVideoPreviewLayer Does not fill the view when iphone changes size

I'm trying to make a QR Code reader. I have a view that has autoresizing for both directions. It goes ok when I try the simulator with the same screen size but when I try it with a bigger screen, the camera doesn't fill the view.

.h file:

@property (strong, nonatomic) IBOutlet UIView *livevideo;

.m file:

 output.rectOfInterest = self.livevideo.bounds;

AVCaptureVideoPreviewLayer *newCaptureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

CGRect bounds=_livevideo.layer.bounds;
newCaptureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
newCaptureVideoPreviewLayer.bounds=bounds;
newCaptureVideoPreviewLayer.position=CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));

[self.livevideo.layer addSublayer:newCaptureVideoPreviewLayer];