title: How to stop captureOutput in iOS app
body: <p>I found tutorial for working with QR codes - <a href="http://www.appcoda.com/qr-code-reader-swift/" rel="nofollow">here it is</a>. Using this method i can get image from device camera and find QR code there.</p>
  
  <p>The problem is that when I change ViewController and even stop the AVCaptureSession - it seems that my camera is still working and device is searching for QR code. So how should I disable captureOutput method?</p>