title: OpenCV for python using VSCode's run stops at 'cv2.VideoCapture(0)' but gives no error
body: <p>I have a python script that uses the OpenCV library. It works correctly from command line and in the idle editor, but when I use the built in run/Start Debugging option in VSCode with the default launch.json file the program seems to run until <code>cap = cv2.VideoCapture(0)</code>, but stops on this line?</p>
  
  <p>Using the same launch.json file, other python files (without OpenCV) have run correctly. The code as follows</p>
  
  <pre><code>import cv2
  import numpy as np
  
  print("Test point 1")
  
  cap = cv2.VideoCapture(0)
  
  print("Test point 2")
  </code></pre>
  
  <p>Outputs the first print statement only</p>
  
  <pre><code>&gt;&gt; Test point 1
  </code></pre>
  
  <p>The program then seems to quit as if it has completed successfully with no errors that would normally come up if there was an error (e.g. undefined variable). So the program seems to run correctly until it reaches the <code>cv2.VideoCapture(0)</code> line.</p>