Display the webcam in Python using OpenCV (cv2)

webcam-cv2.py

"""
Simply display the contents of the webcam with optional mirroring using OpenCV 
via the new Pythonic cv2 interface.  Press <esc> to quit.
"""

import cv2


def show_webcam(mirror=False):
    cam = cv2.VideoCapture(0)
    while True:
        ret_val, img = cam.read()
        if mirror: 
            img = cv2.flip(img, 1)
        cv2.imshow('my webcam', img)
        if cv2.waitKey(1) == 27: 
            break  # esc to quit
    cv2.destroyAllWindows()


def main():
    show_webcam(mirror=True)


if __name__ == '__main__':
    main()

/usr/local/lib/python3.6/dist-packages/google/colab/patches/init.py in cv2_imshow(a)
20 image.
21 """
---> 22 a = a.clip(0, 255).astype('uint8')
23 # cv2 stores colors as BGR; convert to RGB
24 if a.ndim == 3:

AttributeError: 'NoneType' object has no attribute 'clip'
How to fix this error?

I tried running this in Pycharm and I got qt.qpa.plugin: Could not find the Qt platform plugin "cocoa" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

but then I just ran it in the terminal and It worked perfectly so incase anybody else gets that error, try that.

@m-namitha if you are trying to run the script on Google Colab which I'm guessing you are, it won't work and google says that loud and clear. They instead suggest you to use the code snippet provided by colab itself to run such scripts.

explain this man!!!

I know it's kinda late but:

"""
Simply display the contents of the webcam with optional mirroring using OpenCV 
via the new Pythonic cv2 interface.  Press <esc> to quit. 
"""

import cv2


def show_webcam(mirror=False):
    int n = 0 
# use the device /dev/video{n} in this case /dev/video0 
# On windows use the first connected camera in the device tree
    cam = cv2.VideoCapture(n)
    while True:
# read what the camera the images which are comming from the camera
# ret_val idk atm
        ret_val, img = cam.read()
# if mirror is true do flip the image 
        if mirror: 
            img = cv2.flip(img, 1)
# show the image with the title my webcam in a window
        cv2.imshow('my webcam', img)
# if you press ESC break out of the while loop and destroy all windows == free resources <3
        if cv2.waitKey(1) == 27: 
            break  # esc to quit
    cv2.destroyAllWindows()


def main():
    show_webcam(mirror=True)


if __name__ == '__main__':
    main()