Python3 + OpenCV 3.3读取摄像头，保存视频文件

import cv2
##打开摄像头
cap = cv2.VideoCapture(0)

##视频大小设置，获取帧宽度，获取帧高度
sz = (int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)),int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT)))

fps = 20
# 输出格式
# fourcc = cv2.VideoWriter_fourcc('m','p','4','v')
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
# fourcc = cv2.VideoWriter_fourcc('m','p','e','g')
# fourcc = cv2.VideoWriter_fourcc(*'mpeg')

##open and set props
vout = cv2.VideoWriter()
vout.open('output.mp4',fourcc,fps,sz,True)

cnt = 0
while cnt<20:
    cnt += 1
    print(cnt)
    _, frame = cap.read()
    ##putText输出到视频上，各参数依次是：照片/添加的文字/左上角坐标/字体/字体大小/颜色/字体粗细
    cv2.putText(frame,str(cnt),(10,20),cv2.FONT_HERSHEY_PLAIN,1,(0,255,0),1,cv2.LINE_AA)
    vout.write(frame)
vout.release()
cap.release()