OBS virtual camera not starting

[maxicarlos08]

Operating System Info

Other

Other OS

Arch linux

OBS Studio Version

27.0.1

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/HDRJUehL3G_Gu8v4

OBS Studio Crash Log URL

No response

Expected Behavior

When I click the start virtual camera button, the virtual camera should start and be visible to all applications.

Current Behavior

When I click the 'start virtual camera button', it actually asks me for a password to run modprobe but I can't see my camera on any application.

Steps to Reproduce

1. Install OBS (I've tried, pacman, aur and flatpak)
2. Click on the start virtual camera button
3. check if the camera is visible to any application

Anything else we should know?

Apps from where I tried to access my camera:

• QT v4l2 test utility
• Chrome
• Skype (electron)
• VLC

I don't use OBS often so I wouldn't set this to a high priority...

[RytoEX]

07:33:39 PM.923: ================================
07:33:39 PM.925: Warning: OBS is already running!
07:33:39 PM.925: ================================
07:33:39 PM.925: User is now running multiple instances of OBS!

Are you trying to run the Virtual Camera from multiple instances at the same time?

[maxicarlos08]

No, I had an OBS instance running before but closed it, but the virtual camera wasn't working in that previous instance either

[moniquelive]

I don't know if it's related, but on latest PopOS (21.04) w/ kernel 5.11.0-7620-generic the virtual camera works for the first time (it calls gksudo in order to invoke modprobe). If I stop and start again it does nothing (the button says "Start Virtual Camera" forever).

But if I do sudo rmmod v4l2loopback (I need to close OBS Studio first or I get a Module v4l2loopback is in use error message) then I can start it again.

[ctroncoso]

I don't know if it's related, but on latest PopOS (21.04) w/ kernel 5.11.0-7620-generic the virtual camera works for the first time (it calls gksudo in order to invoke modprobe). If I stop and start again it does nothing (the button says "Start Virtual Camera" forever).

But if I do sudo rmmod v4l2loopback (I need to close OBS Studio first or I get a Module v4l2loopback is in use error message) then I can start it again.

Same here with ubuntu 21.04.
First time starting virtualcam, works fine.
Stopping virtualcam doesn't remove v4l2loopback mod even though the button sets to OFF.
Checking v4l2-ctl, the virtual camera is still there.

Trying to click again on start virtual camera fails.

Manually removing v4l2loopback (sudo rmmod v4l2loopback) makes virtualcam work again.

[maxicarlos08]

Now I do see the camera on other applications, but no frames are shown (only a black screen)

[fgadaleta]

on version 27.2.3 linux this is still a problem.
The first time the virtual camera goes fine.
Then I have to close obs, sudo rmmod v4l2loopback manually and open obs again. Only then virtual camera will work again.

[flexiondotorg]

This is a duplicate of #4808

[flexiondotorg]

Edit to add details about umlaeute/v4l2loopback#485

For Ubuntu users, I've made a PPA containing builds of v4l2loopback for 20.04 (Focal), 21.10 (Impish), 22.04 (Jammy), 22.10 (Kinetic) that includes backports of the following patches:

🩹 umlaeute/v4l2loopback#477
🩹 umlaeute/v4l2loopback#485

The patch above fixes the ability to start/stop the Virtual Camera in OBS many times. It *"works for me"*™

The PPA is here:

📦 https://launchpad.net/~flexiondotorg/+archive/ubuntu/v4l2loopback

Feedback welcome. If this fix works widely, I'll work towards landing in the official packages for Ubuntu.

[kkartaltepe]

Closing as duplicate, thanks.