import cv2

RTSP_ADDR = "rtsp://localhost:8554/cam"

cam = cv2.VideoCapture(RTSP_ADDR)

while True:
    result, image = cam.read()

    cv2.imshow("Camera", image)

    if cv2.waitKey(1) & 0xFF == ord("s"):
        cv2.imwrite("capture.png", image)

    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

cam.release()

cv2.destroyWindow("Camera")
cv2.destroyAllWindows()