import numpy as np
import cv2

cap = cv2.VideoCapture('input.mp4')

while(cap.isOpened()):
   ret, frame = cap.read()

   gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

   cv2.imshow('frame',gray)
   if cv2.waitKey(1) & 0xFF == ord('q'):
     break

cap.release()
cv2.destroyAllWindows()