add to documentation octoprint should be part of video group for camera settings to work

[bschwand]

I just debugged an issue where camera settings would not list my camera.
I run octoprint under a different user, and use ustreamer for the camera streaming.
the command using v4l2-ctl to list the cameras in /dev/video* would get a permission denied because the octoprint process did not have access to the video device.

Solution: add user octoprint to group video in /etc/group ( adduser octoprint video)

I do not believe this should be part of the octoprint documentation BTW, AFAIK octoprint only uses the webcam http stream and so there is no need for it to access the hardware in normal setting. Only the plugin camera settings needs that access.

[The-EG]

I would generally expect that a user with enough knowledge to setup something non-standard like that would also know enough to have the users setup properly in the first place, but it doesn't hurt to add it in.

[bschwand]

I do have users setup properly in the first place, I just run octoprint as a non-root user. Retrospectively, yes it's clear the octoprint user needs access to the video devices. However that is not something mentioned explicitely in the octoprint docs, if you do a manual install.