text: import numpy as np
  import cv2
  import argparse
  
  
  parser = argparse.ArgumentParser()
  parser.add_argument("file")
  args = parser.parse_args()
  file = args.file
  
  if not file:
      file=1
  
  cap = cv2.VideoCapture(file)
  #'vtest.avi'
  while(cap.isOpened()):
      ret, frame = cap.read()
  
      #gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
  
      cv2.imshow('frame',frame)
      if cv2.waitKey(1) & 0xFF == ord('q'):
          break
  
  cap.release()
  cv2.destroyAllWindows()
  