camera not responding for opencv videocapture

Question

I intended to work on opencv as a part of my project. I want to take images from the webcam and process them. So I used videocapture(). When I used this the camera is not responding for it. the same program , I tried in both visual studio and jupyter notbook . both resulted the same. The code is as follows:

import cv2 
import matplotlib.pyplot as plt
key = cv2. waitKey(1)
webcam = cv2.VideoCapture(-1)
while True:
    try:
        check, frame = webcam.read()
        print(check) #prints true as long as the webcam is running
        #print(frame) #prints matrix values of each framecd 
        cv2.imshow("Capturing", frame)
        key = cv2.waitKey(1)
        if key == ord('s'): 
            cv2.imwrite(filename='saved_img.jpg', img=frame)
            webcam.release()
            img_new = cv2.imread('saved_img.jpg', cv2.IMREAD_GRAYSCALE)
            img_new = cv2.imshow("Captured Image", img_new)
            cv2.waitKey(1650)
            cv2.destroyAllWindows()
            print("Processing image...")
            img_ = cv2.imread('saved_img.jpg', cv2.IMREAD_ANYCOLOR)
            print("Converting RGB image to grayscale...")
            gray = cv2.cvtColor(img_, cv2.COLOR_BGR2GRAY)
            print("Converted RGB image to grayscale...")
            print("Resizing image to 28x28 scale...")
            img_ = cv2.resize(gray,(28,28))
            print("Resized...")
            img_resized = cv2.imwrite(filename='saved_img-final.jpg', img=img_)
            print("Image saved!")
            plt.show()
            break
        elif key == ord('q'):
            print("Turning off camera.")
            webcam.release()
            print("Camera off.")
            print("Program ended.")
            cv2.destroyAllWindows()
            break
        
    except(KeyboardInterrupt):
        print("Turning off camera.")
        webcam.release()
        print("Camera off.")
        print("Program ended.")
        cv2.destroyAllWindows()
        break

the

print(check)
print(frame)

are returning

False
None

I even tried videocapture(0) and videocapture(-1) Is problem present in my system or in the code how to resolve this issue.

Answer 1

Tip 1: you have an excessive amount of code when your sole objective is to test your webcam - see minimized script to check the cam.
Tip 2: shut down or suspend anti virus. I saw several of times anti virus(kaspersky and maybe AVG) blocking python from opening the webcam (I guess to avoid someone hacking your cam).

import cv2


def cam_test(port: int = 0) -> None:
    cap = cv2.VideoCapture(port)
    if not cap.isOpened():  # Check if the web cam is opened correctly
        print("failed to open cam")
    else:
        print('cam opened on port {}'.format(port))

        for i in range(10 ** 10):
            success, cv_frame = cap.read()
            if not success:
                print('failed to capture frame on iter {}'.format(i))
                break
            cv2.imshow('Input', cv_frame)
            k = cv2.waitKey(1)
            if k == ord('q'):
                break

        cap.release()
        cv2.destroyAllWindows()
    return


if __name__ == '__main__':
    cam_test()