I just installed Python 3.7.4 and OpenCV-Python (using pip) on a reasonably fast desktop PC (I5, 16GB RAM). Using a UbiSoft WebCam that was meant for a Wii but appears in Device Manager as "USB camera" and works in Skype. Trying tutorial (tabs-spacing is messed up in this window; assume correct as it eventually works): import numpy as np import cv2 cap = cv2.VideoCapture(0) while(True): ret, frame = cap.read() gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) cv2.imshow('video', gray) if cv2.waitKey(1) & 0xFF == ord('q'): break cap.release() cv2.destroyAllWindows()* It eventually works but takes about 30 seconds to get the output video displayed.