为什么网络摄像机无法以python代码读取视频供稿？

Question

When I run my python opencv code, the web camera does not read a video feed. There are no any errors, but the black color output with wifi sign and loading sign i there. How to fix that and read the video feed. Here is my code and the output.

import cv2

cap = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (640,480))

print(cap.isOpened())
while(cap.isOpened()):
    ret, frame = cap.read()
    if ret == True:
       print(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
       print(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

       out.write(frame)

       gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
       cv2.imshow('frame', gray)

       if cv2.waitKey(1) & 0xFF == ord('q'):
         break
    else:
        break

cap.release()
out.release()
cv2.destroyAllWindows()

Answer 1

If you are only using one camera you can try the following:

cap = cv2.VideoCapture(-1)

This will pick up the first webcam the system can find. How are you overlaying the wifi/loading signs - I assume they are not part of the webcam feed?