if os_name in ['Windows']: # CAP_DSHOW is required on my windows PC to get 30 FPS
cap = cv2.VideoCapture(args.cam+cv2.CAP_DSHOW)
elif os_name in ['Darwin']: # MAC with CamTwist
cap = cv2.VideoCapture(1)
else: # linux PC is as usual
cap = cv2.VideoCapture(args.cam)