uep
June 10, 2025, 1:16am
1
My OBS virtual camera failed to start after an update last week. I did the usual thing and just rolled back to the previous generation until I had time to look further.
It turns out that there was a v4l2loopback update from 0.13.2 to 0.15, and this is a breaking change for OBS. OBS has addressed this in version 31.1, but that’s yet to be released.
The v4l2loopback commit suggests that it is in turn needed to build newer kernels, so just rolling that back for everyone until OBS updates isn’t quite so easy.
So I did this override instead…
boot.extraModulePackages = [
(pkgs.linuxPackages.v4l2loopback.overrideAttrs
({
version = "0.13.2-manual";
src = (pkgs.fetchFromGitHub {
owner = "umlaeute";
repo = "v4l2loopback";
rev = "v0.13.2";
hash = "sha256-rcwgOXnhRPTmNKUppupfe/2qNUBDUqVb3TeDbrP5pnU=";
});
})
)
];
The version is just a cheap hack to avoid pulling in the kernel to get the version in this particular module.
Have added the same note to the commit, but thought I’d post it here to make it easier to find.
1 Like
uep
July 6, 2025, 10:17pm
2
as of the latest unstable bump at 5c724ed, this is no longer necessary, as OBS has been updated (to a 31.0.4 patch release that includes the fix)
heuzef
July 13, 2025, 9:23pm
3
Hi @uep
Need this fix too. Do you know when this will be avaible on 25.05 channel ? It’s look like it’s aleready the case on the NixOS website but it’s not :
nix-env -f "https://github.com/NixOS/nixpkgs/archive/refs/tags/25.05.tar.gz" -qaP obs-studio
unpacking 'https://github.com/NixOS/nixpkgs/archive/refs/tags/25.05.tar.gz' into the Git cache...
obs-studio obs-studio-31.0.3
Thanks !
I’m using the OBS “Screen Capture (PipeWire)”, which seems ok. It was working, then I updated to the latest stable and it broke. After a bit of help from Cursor, I installed a few more packages and configured gnome a little bit better, and it’s back to working again.
uep
July 13, 2025, 11:18pm
5
the PR with the update is
master
← fpletz:pkgs/obs-studio-31.0.4
opened 07:16AM - 30 Jun 25 UTC
https://github.com/obsproject/obs-studio/releases/tag/31.0.4
Fix #420729.
… ## Things done
- Built on platform(s)
- [x] x86_64-linux
- [ ] aarch64-linux
- [ ] x86_64-darwin
- [ ] aarch64-darwin
- For non-Linux: Is sandboxing enabled in `nix.conf`? (See [Nix manual](https://nixos.org/manual/nix/stable/command-ref/conf-file.html))
- [ ] `sandbox = relaxed`
- [ ] `sandbox = true`
- [ ] Tested, as applicable:
- [NixOS test(s)](https://nixos.org/manual/nixos/unstable/index.html#sec-nixos-tests) (look inside [nixos/tests](https://github.com/NixOS/nixpkgs/blob/master/nixos/tests))
- and/or [package tests](https://github.com/NixOS/nixpkgs/blob/master/pkgs/README.md#package-tests)
- or, for functions and "core" functionality, tests in [lib/tests](https://github.com/NixOS/nixpkgs/blob/master/lib/tests) or [pkgs/test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/test)
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- [x] Tested basic functionality of all binary files (usually in `./result/bin/`)
- [Nixpkgs 25.11 Release Notes](https://github.com/NixOS/nixpkgs/blob/master/doc/release-notes/rl-2511.section.md) (or backporting [24.11](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/release-notes/rl-2411.section.md) and [25.05](https://github.com/NixOS/nixpkgs/blob/master/doc/manual/release-notes/rl-2505.section.md) Nixpkgs Release notes)
- [ ] (Package updates) Added a release notes entry if the change is major or breaking
- [NixOS 25.11 Release Notes](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2511.section.md) (or backporting [24.11](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2411.section.md) and [25.05](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2505.section.md) NixOS Release notes)
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The corresponding backport is
release-25.05
← backport-421175-to-release-25.05
opened 09:36AM - 30 Jun 25 UTC
Bot-based backport to `release-25.05`, triggered by a label in #421175.
* [x] B… efore merging, ensure that this backport is [acceptable for the release](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#changes-acceptable-for-releases).
* Even as a non-committer, if you find that it is not acceptable, leave a comment.
It looks like that’s just waiting for the next successful build cycle before the channel advances:
https://nixpk.gs/pr-tracker.html?pr=421198
Edit: caffeine hadn’t yet kicked in…
Edit2: Looks like it just landed
heuzef
July 15, 2025, 8:10am
6
So strange, i force update and i expected to an update on 3.0.4. instead of that, update on 31.1.0 i don’t know why. But i get the fix and solve the problem with virtual cam
uep
July 15, 2025, 8:17am
7
the latest unstable, as of just a couple of hours ago, includes the 31.1 release… I just got it too.
1 Like