If you just want to play an mp4 video, then this opencv program will help you to do that.
import cv2
cap = cv2.VideoCapture("v2.mp4")
ret, frame = cap.read()
while(1):
ret, frame = cap.read()
cv2.imshow('frame',frame)
if cv2.waitKey(1) & 0xFF == ord('q') or ret==False :
cap.release()
cv2.destroyAllWindows()
break
cv2.imshow('frame',frame)