cap = cv2.VideoCapture(path_to_video)
if not cap.isOpened():
    print "Failed to open video."
    exit(1)

prev_frame = None
while(True):
    state, frame = cap.read()
    if not state:
        break # Reached end of video

    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    if prev_frame is not None:
        matches_gms = match(prev_frame, frame)
    prev_frame = frame

cap.release()