OpenCv error can't open camera through video capture

Question

I was using my cam through opencv and suddenly after restarting I ran my code it shows below error:

[ WARN:0] global /io/opencv/modules/videoio/src/cap_v4l.c         


        

Answer 1

Most likely a permission issue on /dev/video0.

Check if you are part of "video" group.
id -a

if you don't see video in your group list add sudo usermod -a -G video

for Ubuntu users:(20.04)
sudo usermod -a -G video $LOGNAME

Logout and log back in and try it.