import cv2

cap = cv2.VideoCapture(2)

cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)

while True:
    _, frame = cap.read()
    grey = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    _, thresh = cv2.threshold(grey, 127, 255, cv2.THRESH_BINARY)
    cv2.imshow('original', frame)
    cv2.imshow('thresh', thresh)
    cv2.waitKey(1)