“ with”关键字不适用于python中的“ cv2.VideoCapture（0）”

Question

代码：

import cv2
import numpy as np

with cv2.VideoCapture(0) as cap:
    while True:
        ret, frame = cap.read()
        cv2.imshow("Title", frame)

        if cv2.waitKey(1):
            break

        cv2.destroyAllWindows()`

抛出错误：  “ 回溯（最近通话最近）：   文件“ D：/Python/openCV/Basic_Video/Basic.py”，第4行，在     以cv2.VideoCapture（0）为上限： AttributeError：__enter __ “

Answer 1

with不支持VideoCapture关键字。我发现的所有示例总是首先声明它：

How to process images of a video, frame by frame in video streaming using Opencv python

https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html

cv2.videocapture.read() does not return a numpy array