Detect video function

If we want to track a person or vehicle in a video, we can use the following function:

def detect_video(video, yolo, all_classes):
    """Use yolo v3 to detect video.

    # Argument:
        video: video file.
        yolo: YOLO, yolo model.
        all_classes: all classes name.
    """
    video_path = os.path.join("videos", "test", video)
    camera = cv2.VideoCapture(video_path)
    cv2.namedWindow("detection", cv2.WINDOW_AUTOSIZE)

    # Prepare for saving the detected video
    sz = (int(camera.get(cv2.CAP_PROP_FRAME_WIDTH)),
        int(camera.get(cv2.CAP_PROP_FRAME_HEIGHT)))
    fourcc = cv2.VideoWriter_fourcc(*'mpeg')

    
    vout = cv2.VideoWriter()
    vout.open(os.path.join("videos", "res", video), fourcc, 20, sz, True)

    while True:
        res, frame = camera.read()

        if not res:
            break

        image = detect_image(frame, yolo, all_classes)
        cv2.imshow(&quot...