Adding and removing v4l2-loopback devices?

Question

I have different lxc containers running on my machine and a webcam is also attached. I want all of the lxc containers to access this camera. I came across 'v4l2-loopback' devices and found a way to add devices using;

modprobe v4l2loopback devices=3

And I directed the stream from /dev/video0 to the desired virtual video devices. My question is how to add and remove these v4l2loopback devices at runtime? I want to add/remove a device whenever any lxc container is launched/deleted. Any ideas?

Thanks!

score 8 · Answer 1 · answered Mar 02 '18 at 22:46

8

I don't have an elegant way to remove these devices other than force remove the v4l2loopback module:

sudo modprobe -r v4l2loopback

answered Mar 02 '18 at 22:46

user278684

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After I run this command it gives me no output. I dont know if it removed anything.... – Rodrigo Graça May 24 '20 at 21:47
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You can use `v4l2-ctl --list-devices` to check your virtual devices – Marcelo Bittencourt Apr 26 '21 at 21:49

score 0 · Answer 2 · answered Dec 21 '22 at 17:18

If you are running the full up to date v4l2loopback driver from https://github.com/umlaeute/v4l2loopback, then you can use the v4l2loopback-ctl utility to add and remove devices while the module is installed using the command v4l2loopback-ctl add /dev/video2 and v4l2loopback-ctl delete /dev/video2.

Unfortunately, this is not the version that is currently in Debian, which is a mishmash of an old version and some code from the current version, and is still using the old (pre 2021) v4l2loopback-ctl and the driver with no dynamic device management.

Adding and removing v4l2-loopback devices?

2 Answers2