PipeWire status tracking issue

[jansol]

TL;DR: Things are generally in pretty good shape but wireplumber can't be configured via the nixos module yet. On the other hand most people won't need to change anything from the defaults.

If you are reporting something, please mention the pipewire version you are using, as it is updated very frequently. Bonus points for checking if upstream already has a fix mentioned in the commit log or release notes.

Currently on master:

• nixos service exists and works (socket-activated systemd user service)
• alsa and JACK compatibility shims can be enabled with options
• pulse-bridge, a fake pulse server enabled with the pulse option (socket-activated systemd user service)
• bluetooth (loaded by the pulseaudio module)
• wireplumber (Packaged and usable but can't be configured via nixos modules yet. Custom config files can be placed in ~/.config/wireplumber)

Configuration

Most basic additions to configuration.nix, this should be enough for most people:

  # Remove sound.enable or turn it off if you had it set previously, it seems to cause conflicts with pipewire
  #sound.enable = false;

  # rtkit is optional but recommended
  security.rtkit.enable = true;
  services.pipewire = {
    enable = true;
    alsa.enable = true;
    alsa.support32Bit = true;
    pulse.enable = true;
    # If you want to use JACK applications, uncomment this
    #jack.enable = true;
  };

Some useful knobs if you want to finetune or debug your setup. Note that pipewire config keys may contain a period '.' so they need to be quoted in Nix. (combine these with the basic config above):

  services.pipewire = {
    config.pipewire = {
      "properties" = {
        #"link.max-buffers" = 64;
	"link.max-buffers" = 16; # version < 3 clients can't handle more than this
	"log.level" = 2;
        #"default.clock.rate" = 48000;
        #"default.clock.quantum" = 1024;
        #"default.clock.min-quantum" = 32;
        #"default.clock.max-quantum" = 8192;
    };
  };

Virtual Sinks/Sources

If you want to do some fancy routing with null sinks, you can define them directly in the pipewire config like this. Especially convenient if you have a multi-channel (8+, or something "weird" like 2x2, 3x2) soundcard that keeps confusing applications with too many channels or a bad channel layout. (Note: you can set those cards to the "Pro Audio" profile with pavucontrol so pipewire doesn't try to guess a wrong channel layout for them.) Note that arrays are replaced rather than merged with defaults, so you need to list any default items that you want to keep here (the dummy and freewheeling driver for JACK applications, if you have JACK support enabled):

  services.pipewire = {
    config.pipewire = {
      "context.objects" = [
        {
          # A default dummy driver. This handles nodes marked with the "node.always-driver"
          # properyty when no other driver is currently active. JACK clients need this.
          factory = "spa-node-factory";
          args = {
            "factory.name"     = "support.node.driver";
            "node.name"        = "Dummy-Driver";
            "node.group"       = "pipewire.dummy";
            "priority.driver"  = 20000;
          };
        }
        {
          # Freewheeling driver. This is used e.g. by Ardour for exporting projects faster than realtime.
          factory = "spa-node-factory";
          args = {
            "factory.name"     = "support.node.driver";
            "node.name"        = "Freewheel-Driver";
            "node.group"       = "pipewire.freewheel";
            "node.freewheel"   = true;
            "priority.driver"  = 19000;
          };
        }
        {
          factory = "adapter";
          args = {
            "factory.name"     = "support.null-audio-sink";
            "node.name"        = "Microphone-Proxy";
            "node.description" = "Microphone";
            "media.class"      = "Audio/Source/Virtual";
            "audio.position"   = "MONO";
          };
        }
        {
          factory = "adapter";
          args = {
            "factory.name"     = "support.null-audio-sink";
            "node.name"        = "Main-Output-Proxy";
            "node.description" = "Main Output";
            "media.class"      = "Audio/Sink";
            "audio.position"   = "FL,FR";
          };
        }
      ];
    };
  };

You can't currently link nodes to each other in the config, but you can adapt this script to do it for you. Replace the soundcard names and ports with whatever matches your setup:

#!/usr/bin/env bash

# ports obtained from `pw-link -io`

pw-link "Main-Output-Proxy:monitor_FL" "alsa_output.usb-Native_Instruments_Komplete_Audio_6_69BC86B9-00.pro-output-0:playback_1"
pw-link "Main-Output-Proxy:monitor_FR" "alsa_output.usb-Native_Instruments_Komplete_Audio_6_69BC86B9-00.pro-output-0:playback_2"

pw-link "alsa_input.usb-M-Audio_Fast_Track-00.pro-input-0:capture_1" "Microphone-Proxy:input_MONO"

Standalone mode (no session manager)

If you want to run a minimal pipewire instance with no session manager for automatic switching etc, you can do that as of 0.3.46 (technically pipewire supported it a bit longer than that but that's when the nixos module was adapted to account for it). This is mainly intended for systems that used to run purely JACK:

  security.rtkit.enable = true;
  services.pipewire = {
    enable = true;
    jack.enable = true;
    wireplumber.enable = false;
    media-session.enable = false;
  };

If this doesn't work it is likely because it defaults to using an alsa device called hw:0 which might not be the sound card you want to be using. You can easily fix this by overriding the device name in the "context.objects" array of the main pipewire configuration. The names and descriptions of available devices can be seen with aplay -l from the alsa-utils package. Note that you'll have to write out the full contents of the array because the default items will be replaced completely with this:

  services.pipewire.config.pipewire = {
      "context.objects" = [
        {
          factory = "metadata";
          args = {
            "metadata.name" = "default";
          };
        }
        {
          # A default dummy driver. This handles nodes marked with the "node.always-driver"
          # properyty when no other driver is currently active. JACK clients need this.
          factory = "spa-node-factory";
          args = {
            "factory.name"     = "support.node.driver";
            "node.name"        = "Dummy-Driver";
            "node.group"       = "pipewire.dummy";
            "priority.driver"  = 20000;
          };
        }
        {
          # Freewheeling driver. This is used e.g. by Ardour for exporting projects faster than realtime.
          factory = "spa-node-factory";
          args = {
            "factory.name"     = "support.node.driver";
            "node.name"        = "Freewheel-Driver";
            "node.group"       = "pipewire.freewheel";
            "node.freewheel"   = true;
            "priority.driver"  = 19000;
          };
        }
        {
          args = {
          "adapter.auto-port-config" = {
            mode = "dsp";
            monitor = false;
            position = "unknown";
          };
          "api.alsa.path" = "hw:0"; # replace with the right path for your system
          "channelmix.disable" = true;
          "factory.name" = "api.alsa.pcm.source";
          "media.class" = "Audio/Source";
          "node.description" = "system";
          "node.name" = "system";
          "node.suspend-on-idle" = true;
          "resample.disable" = true;
          };
          factory = "adapter";
        }
        {
          args = {
          "adapter.auto-port-config" = {
            mode = "dsp";
            monitor = false;
            position = "unknown";
          };
          "api.alsa.path" = "hw:0"; # replace with the right path for your system
          "channelmix.disable" = true;
          "factory.name" = "api.alsa.pcm.sink";
          "media.class" = "Audio/Sink";
          "node.description" = "system";
          "node.name" = "system";
          "node.suspend-on-idle" = true;
          "resample.disable" = true;
          };
          factory = "adapter";
        }
      ];
    };
  };

Miscellaneous

For the time being you can switch between two session managers, although there is usually no reason to. Note #159546 which intends to change the default from media-session to wireplumber since media-session is considered deprecated by upstream.

  services.pipewire = {
    # wireplumber.enable = true;
    # media-session.enable = false;
  }

For other available options, consult the upstream config templates. All config files listed there should be accessible via the nixos module as services.pipewire.config.$basename and services.pipewire.media-session.config.$basename for the daemon and the default session manager respectively.

Please help test new PRs!

Please do try out update pull requests before they are merged (if you can), it is fairly easy:

• Make a local clone of nixpkgs
• Fetch the PR branch to your clone of nixpkgs
• (It might be a good idea to cherry-pick or rebase the PR on top of your release channel branch instead of master)
• Build your system configuration using the cloned nixpkgs instead of the configured channel: sudo nixos-rebuild test -I nixpkgs=path/to/nixpkgs/clone
  • Useful nixos-rebuild verbs besides the usual "switch" and "boot" are: "build" and "test" (build and enable but don't change boot)

Known Problems

The issues people have previously described here should all be fixed now.

Please add a comment if something is broken (and ideally open an issue upstream if it is not a packaging problem).

[eadwu]

From my experience

• With default configuration
  • Bluetooth
    • Works fine for a small amount of time, before crapping out and going out of sync
  • On high load
    • Well let's just say it isn't pretty but not unusable
• With tweaked configuration (don't ask how to tweak, I don't know, or at least it needs tweaking outside of the pipewire configuration as well)
  • Bluetooth
    • I haven't had any out of sync yet, though I do have some intermittent audio loss but at least it still stays in sync
  • On high load
    • Better but still pretty distinctive

There are other things that are pretty annoying, audio control is completely bonkers for me, alsactl/alsamixer is half broken, I have to rely on using pactl and the pulseaudio library shims to even change my audio with keybinds. Anyway just a couple of things off the top of my head.

Note that you may not experience some of my issues, because it's configuration dependent on more than just the pipewire configuration.

As of November 14, 2020, all of the issues I've listed have been resolved (on my system). HFP/HSP doesn't work the last time checked that out, as only the backend support is implemented, in case that is a deal breaker for anyone (as far as I can remember).

[jansol]

Did some digging and the Discord issue is fairly simple: the wrapper prepends the dependencies' paths to LD_LIBRARY_PATH, and those dependencies include libpulseaudio. So I tried making a copy of the wrapper script that prepends the pipewire pulseaudio shim's path instead of the native pulseaudio one and voilà, it works perfectly! Simply removing the libpulseaudio part from LD_LIBRARY_PATH works as well, as long as the result does not put the native libpulseaudio before the pipewire shim.

I'm guessing the Right solution to this is to wait for the pulse-bridge aka "fake" pulseaudio server in pipewire so Discord (and presumably steam) can just use the native library and everything looks like business as usual to them.

[jansol]

Pulse-bridge does seem to work surprisingly well: I tried stopping the pipewire service and launching it manually with pulse-bridge enabled (I have pulseaudio disabled in my nixos config so there won't be conflicts): pipewire-media-session -e pulse-bridge
If steam, discord etc is launched after starting the media session, audio is working without further tweaking as expected. If they were running before this, they will likely crash or lock up when pipewire is stopped.

So for transparent support we'll need a nixos option to enable the pulse-bridge module as described upstream. Some discussion about that happened in #102514 .

The same approach could be used for the bluez5 module which is also disabled by default for now.

[jansol]

Upstream has deprecated the libpulseaudio.so shim and provides a systemd service to load pulse-bridge now. This makes packaging a lot easier since we don't have to patch files and there should no longer be socket conflicts with pulseaudio either.

[ilya-fedin]

ALSA compatibility option doesn't provide ctl.!default for some reason:

nixpkgs/nixos/modules/services/desktops/pipewire.nix

Lines 85 to 98 in c18b90b

	sound.extraConfig = mkIf cfg.alsa.enable ''
	pcm_type.pipewire {
	libs.native = ${pkgs.pipewire.lib}/lib/alsa-lib/libasound_module_pcm_pipewire.so ;
	${optionalString enable32BitAlsaPlugins
	"libs.32Bit = ${pkgs.pkgsi686Linux.pipewire.lib}/lib/alsa-lib/libasound_module_pcm_pipewire.so ;"}
	}
	pcm.!default {
	@func getenv
	vars [ PCM ]
	default "plug:pipewire"
	playback_mode "-1"
	capture_mode "-1"
	}
	'';

This leads to the impossibility to control pipewire via alsamixer :(

[jansol]

0.3.16 has been merged, this adds pulse-bridge which fixes most pulseaudio applications including steam and its games. (channels haven't updated yet at the time of writing though)

[ilya-fedin]

0.3.16 has been merged

0.3.17 just released ;)

[gebner]

With 0.3.17, bluetooth works out of the box for me (both HFP and A2DP). #105362

[jansol]

Isn't the bluez5 module disabled by default?

[ilya-fedin]

Isn't the bluez5 module disabled by default?

#105362 enables it by the with-pulse file