MatchParser.py 文件源码

def spaced_frames(parser, start=None, end=None, interval=None, num_samples=None, fuzz=4):
    if (interval is None and num_samples is None) or None not in (interval, num_samples):
        raise ValueError('exactly one of (interval, num_samples) must be set')

    vc = cv2.VideoCapture(parser.stream)
    video_length = vc.get(7) / vc.get(5)
    if not start or start < 0:
        start = 0
    if not end or end > video_length:
        end = video_length

    total_time = end - start

    if not num_samples:
        num_samples = total_time // interval

    for time in np.linspace(start, end, num=num_samples):
        time += randint(-1 * fuzz, fuzz) / vc.get(5)
        time = min([max([0, time]), total_time])
        vc.set(0, int(time * 1000))
        success, frame = vc.read()

        if success:
            yield (time, cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY))
    return