Just reading a movie with opencv in python, jumping to a frame and displaying

read_movie.py

    cap = cv2.VideoCapture('/opt/home/garybradski/data/matte_this/shot02/Tornado.mp4')
    length = int(cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT))
    print "len Tornado = ", length
    cv2.namedWindow('Tornado', cv2.WINDOW_NORMAL)
    cv2.resizeWindow('Tornado',960,540)
    # seek
    assert cap.set(cv2.cv.CV_CAP_PROP_POS_FRAMES, 8000)
    n = 0
    wait_key = 30
    while True:
        ret, frame = cap.read()
        if n > length:
            break
        if not ret:
            break
        cv2.imshow('Tornado', frame)
        #key handling
        k = cv2.waitKey(wait_key) & 0xff
        if chr(k) == 'r':   #start running
            wait_key = 30
        elif chr(k) == 'p': #pause between frames
            wait_key = 0
        elif k == 27:       #end processing
            break
    return