title: Are there issues with openCV 3 for python 3 on mac
body: <p>I am not able to read the video file using .VideoCapture('filename.avi') constructor in mac using opencv3 with python3. It opens the file but .read() method is returning (false, none).</p>
  
  <pre><code>import numpy as np
  import cv2
  cap = cv2.VideoCapture('vtest.avi')
  while(cap.isOpened()):
      ret, frame = cap.read()
      gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
      cv2.imshow('frame',gray)
      if cv2.waitKey(1) &amp; 0xFF == ord('q'):
          break
  cap.release()
  cv2.destroyAllWindows()
  </code></pre>