How to do audio production in Silverblue?

I’m extremely confused on the pro audio workflow when using Fedora Silverblue. It’s been years since I don’t do this kind of stuff, so my knowledge might be a bit outdated. In any case, I haven’t been able to make it work.

My use case is simple. What I want is:

  1. Record some live music.
  2. Mix it with Ardour.
  3. Apply some effects, using JACK.
    AFAIK you should start Jack and then plug desired apps to make it work. But in Silverblue, you’re supposed to install apps as flatpaks.

I read recently this blog post, which explains recent pro audio progress in Fedora, Flatpak, PipeWire for JACK support and such stuff. Quoting under next steps:

Flatpak portal for JACK/audio applications – The future of application packaging is Flatpaks and being able to sandbox Jack applications properly inside a Flatpak is something we want to enable.

According to this, I understand that for Fedora 33, there’s still no support for using Flatpak’d apps that connect to JACK… right?

Because I installed Cadence and Carla through rpm-ostree and also Ardour from Flathub, and I can find no way of making Ardour find JACK after starting it. It simply doesn’t find the JACK server. Only Pulseaudio and ALSA.

Another weird thing is that when I start JACK with Cadence, I get this error:

But then if I open a terminal and try to add myself to that group, it says it doesn’t exist, although there are limits configured for it:

$ cat /etc/security/limits.d/audio.conf
# Provided by the studio-controls package. In case jackd is not installed
# or is not installed correctly
# Changes to this file will be preserved.
# If you want to enable/disable realtime permissions, run
#    dpkg-reconfigure -p high jackd

@audio   -  rtprio     95
@audio   -  memlock    unlimited
#@audio   -  nice      -19

$ sudo usermod -aG audio $USER
usermod: group 'audio' does not exist

:man_facepalming: Yikes this is all so confusing!

At least Carla seems to work fine:

So, for Fedora 33 Silverblue, is there a way to use the Flatpak’d apps that need JACK? Or to configure it to rely on PipeWire? Or should I just install all pro audio apps through rpm-ostree and wait for F34 where this should be mainstreamed?

Hello @yajo,
For adding someone to the libvirt group on silverblue for example, you would use grep -E '^libvirt:' /usr/lib/group >> /etc/group then usermod -aG libvirt username, check out this link for details I would think replacing audio for libvirt in the example I noted should work. You should install the flatseal flatpak app to view/edit the permissions and port access available to the flatpak you are trying to get access to jack with. Also, the following link is to an article a contributor did on using Fedora for audio recording/mixing/effects etc… though this is from the WS POV it does cover the state of fedora for this use.

I already used flatseal in other scenarios. How does one add JACK access to it?

Am I right assuming the JACK server must be installed with rpm-ostree?

I don’t know how Jack Audio would be used by the flatpak, I am assuming it would require the flatpak to have more than normal privileges in order to access it. I believe you are correct in thinking the jack audio package needs to be layered.

If this works for you then it is fine. You don’t have to force yourself to use Flatpaks if the support isn’t there yet. Overlaying packages still gives you most of the benefits of Silverblue.

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“… build without Jack Audio support because Jack doesn’t work from inside Flatpak …”

Still very early for Jack and FlatPack.
On some Flatpack, Jack is available through PipeWire, but the work has not been extended to all Audio apps yet. It depends whether you want to do Music or debug application :slight_smile:
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I have been using Silverblue for everything for around a year now, it’s the only operating system installed on my laptop.

However, there is another computer on my desk, which you might be unsurprised to hear is used only for audio - and some video - production. It has Fedora 32 Workstation, with the couple of apps I use and, crucially, Jack audio.

Even if all this stuff starts working in Silverblue 34, I’ll probably keep the current arrangement as it is; it also saves my “work” computer SSD from filling up.

For the time being, thanks to all comments here, I’ve been able to set up my desired apps using rpm-ostree, which is not so nice because it means one restart each time, but well… it’s done now and possible.

I wish we have pipewire soon. Having pro audio stuff working out of the box in flatapked apps must be a real pleasure!