I know it's a late reply but this post was the number 1 google result for something else I was looking up so thought id give an answer that should work.
try: rtsp://user:password@nvrIpAddress/Streaming/channels/001/?transportmode=unicast
This should work as a basic python3.x script to view it :
#------------------------------------------------------------------------------------------------------
import cv2
import numpy as np
cap = cv2.VideoCapture('rtsp://user:password@nvrIpAddress/Streaming/channels/001/?transportmode=unicast')
while(True):
ret, frame = cap.read()
cv2.imshow('frame',frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()