title: OpenCV Video Output image not showing
body: <pre><code>import numpy as np
  import cv2
  
  cap = cv2.VideoCapture(0)
  
  while(True):
      # Capture frame-by-frame
      ret, frame = cap.read()
  
      cv2.imshow('frame',frame)
  </code></pre>
  
  <p>Why is the camera preview is not showing on the output screen/frame?</p>
  
  <p>Here is the screenshot of the output</p>
  
  <p><a href="https://i.stack.imgur.com/ga8LT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ga8LT.png" alt=""></a></p>