读取摄像头内容，然后保存一段十秒钟的视频。

import cv2

cameraCapture = cv2.VideoCapture(0)

fps = 30 # an assumption

size = (int(cameraCapture.get(cv2.cv.CV_CAP_PROP_FRAME_WIDTH)),int(cameraCapture.get(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT)))

videoWriter = cv2.VideoWriter('MyOutputVid.avi', cv2.cv.CV_FOURCC('I','4','2','0'), fps, size)

success, frame = cameraCapture.read()

numFramesRemaining = 10 * fps - 1

while success and numFramesRemaining > 0:

    videoWriter.write(frame)

    success, frame = cameraCapture.read()

    numFramesRemaining -= 1