Opencv-python: VIDEOIO ERROR: V4L: can't open camera by index 0

[chtsngn]

Hello,

I'm triggering a Python file with PHP.

$return = shell_exec("/usr/bin/python3.6 create.py 2>&1")

Python File

import numpy as np
import cv2

cap = cv2.VideoCapture(0)

while(True):

    ret, frame = cap.read()

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

    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

Return this value

VIDEOIO ERROR: V4L: can't open camera by index 0

What is the problem?

OS: Ubuntu 18.04 x64
Python: 3.6.6
OpenCV: 3.4.2

[skvark]

Try with cv2.VideoCapture(-1). Please ask this kind of questions at http://answers.opencv.org/questions/ in the future.

[chtsngn]

http://answers.opencv.org/question/199105/videoio-error-v4l-cant-open-camera-by-index-0/

[adarsh1927]

thanks to skvark for solving my problem. -1 is a solution for my code which I have written in ubuntu