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PipeWire is a new low-level multimedia framework. It aims to offer capture and playback for both audio and video with minimal latency and support for PulseAudio-, JACK-, ALSA- and GStreamer-based applications.
 
[https://www.pipewire.org/ PipeWire] is a relatively new (first release in 2017) low-level multimedia framework. It aims to offer capture and playback for both audio and video with minimal latency and support for [[PulseAudio]]-, [[JACK]]-, [[ALSA]]- and [[GStreamer]]-based applications. PipeWire has a great [[Bluetooth|bluetooth]] support: because Pulseaudio was [https://github.com/NixOS/nixpkgs/issues/123784 reported to have troubles with bluetooth], PipeWire can be a good alternative.


The daemon based on the framework can be configured to be both an audio server (with PulseAudio and JACK features) and a video capture server.
The daemon based on the framework can be configured to be both an audio server (with PulseAudio and JACK features) and a video capture server.


==Enabling PipeWire==
PipeWire also supports containers like [[Flatpak]] and does not rely on <code>audio</code> and <code>video</code> user groups, but rather it uses a [[Polkit]]-like security model, asking Flatpak or [[Wayland]] for permission to record screen or audio.
Add to your configuration:
 
As of [https://nixos.org/manual/nixos/stable/release-notes#sec-release-24.11 NixOS 24.11], PipeWire is the default sound server for most graphical sessions.
 
==Configuring PipeWire==
<syntaxhighlight lang="nix">
  # rtkit is optional but recommended
  security.rtkit.enable = true;
  services.pipewire = {
    enable = true; # if not already enabled
    alsa.enable = true;
    alsa.support32Bit = true;
    pulse.enable = true;
    # If you want to use JACK applications, uncomment this
    #jack.enable = true;
  };
</syntaxhighlight>
 
It is possible to use the <code>services.pipewire.extraConfig</code> option hierarchy in NixOS to create drop-in configuration files, if needed.
 
==Bluetooth Configuration==
PipeWire can be configured to use specific codecs, by default all codecs and most connection modes are enabled, see [https://pipewire.pages.freedesktop.org/wireplumber/daemon/configuration/bluetooth.html#monitor-properties this link] for precise details of which connections modes are enabled by default. The mSBC codec provides slightly better sound quality in calls than regular HFP/HSP, while the SBC-XQ provides better sound quality for audio listening. For more information [https://www.guyrutenberg.com/2021/03/11/replacing-pulseaudio-with-pipewire/ see this link].
 
Wireplumber (<code>services.pipewire.wireplumber</code>) is the default modular session / policy manager for PipeWire in unstable. To add custom configuration you can use <code>services.pipewire.wireplumber.extraConfig</code> directly. For example:
 
<syntaxhighlight lang="nix">
  services.pipewire.wireplumber.extraConfig."10-bluez" = {
    "monitor.bluez.properties" = {
      "bluez5.enable-sbc-xq" = true;
      "bluez5.enable-msbc" = true;
      "bluez5.enable-hw-volume" = true;
      "bluez5.roles" = [
        "hsp_hs"
        "hsp_ag"
        "hfp_hf"
        "hfp_ag"
      ];
    };
  };
</syntaxhighlight>{{Note|This config may break wireplumber, so that the following options were no longer available for Bluetooth headsets
 
- High Fidelity Playback (A2DP Sink, codec SBC)
 
- High Fidelity Playback (A2DP Sink, codec SBC-XQ)
 
- High Fidelity Playback (A2DP Sink, codec AAC)}}
 
Or, to disable automatic HSP/HFP and A2DP mode switching, which is part of the <code>11-bluetooth-policy</code> configuration:<syntaxhighlight lang="nix">
  services.pipewire.wireplumber.extraConfig."11-bluetooth-policy" = {
    "wireplumber.settings" = {
      "bluetooth.autoswitch-to-headset-profile" = false;
    };
  };
</syntaxhighlight>Alternatively you can set <code>services.pipewire.wireplumber.configPackages</code> as well, adding derivations that output wireplumber config files in <code>$out/share/wireplumber/wireplumber.conf.d/*.conf</code>:
 
<syntaxhighlight lang="nix">
  services.pipewire.wireplumber.configPackages = [
    (pkgs.writeTextDir "share/wireplumber/wireplumber.conf.d/10-bluez.conf" ''
      monitor.bluez.properties = {
        bluez5.enable-sbc-xq = true
        bluez5.enable-msbc = true
        bluez5.enable-hw-volume = true
        bluez5.roles = [hsp_hs hsp_ag hfp_hf hfp_ag]
      }
    '')
  ];
</syntaxhighlight>
 
It is possible change a particular user instead of system-wide, with adding this to <code>~/.config/wireplumber/bluetooth.conf.d</code> (<code>~/.config/wireplumber/bluetooth.lua.d</code> for wireplumber 4.X and below) instead, manually or using [[Home Manager]]. Refer to [https://wiki.archlinux.org/title/PipeWire ArchWiki] for possible configurations, as well as the [https://docs.pipewire.org/ Full Documentation].
 
==AirPlay/RAOP configuration==
 
Remote Audio Output Protocol, branded as AirPlay, is the apple-developed wireless audio stack used in apple devices, many "smart speakers" and similar appliances as well as several open source implementations. It's based on RTSP, streams in PCM and is supported natively by PipeWire. With the following configuration AirPlay servers on your local network should be automatically added as output devices:


<syntaxHighlight lang="nix">
<syntaxhighlight lang="nix">
# Remove sound.enable or turn it off if you had it set previously, it seems to cause conflicts with pipewire
# avahi required for service discovery
#sound.enable = false;
services.avahi.enable = true;


# rtkit is optional but recommended
security.rtkit.enable = true;
services.pipewire = {
services.pipewire = {
  enable = true;
   # opens UDP ports 6001-6002
  alsa.enable = true;
   raopOpenFirewall = true;
  alsa.support32Bit = true;
  pulse.enable = true;
   # If you want to use JACK applications, uncomment this
   #jack.enable = true;


   # use the example session manager (no others are packaged yet so this is enabled by default,
   extraConfig.pipewire = {
  # no need to redefine it in your config for now)
    "10-airplay" = {
   #media-session.enable = true;
      "context.modules" = [
        {
          name = "libpipewire-module-raop-discover";
 
          # increase the buffer size if you get dropouts/glitches
          # args = {
          #   "raop.latency.ms" = 500;
          # };
        }
      ];
    };
  };
};
};
</syntaxhighlight>
Note that to set up an airplay server as opposed to a client, separate software is required.
==Graphical tools==
All protocols (Pulseaudio/JACK) are now talking to the PipeWire protocol and are managed by the PipeWire daemon (therefore, applications can be managed by both Pulseaudio and JACK tools). For that reason, all graphical tools used for these protocols can be used:
* pavucontrol: controls the volume (per-sink and per-app basis), the default outputs/inputs, the different profiles (for HDMI outputs/bluetooth devices), routes each application to a different input/output, etc.
* plasma-pa: a [[KDE|Plasma]] applet to change volume directly from the systray. Also deals with volume keys.
* qjackctl: with JACK emulation, provides a patchbay (to connect applications together). Note that JACK does not provide any way to change the volume of a single application; use Pulseaudio tools for that purpose.
* carla: with JACK emulation, provides a patchbay (make sure to go to "Patchbay" tab and check "Canvas > Show External").
* catia/patchage: similar to qjackctl and carla.
* [https://gitlab.freedesktop.org/pipewire/helvum Helvum]: GTK-based patchbay for PipeWire (uses the PipeWire protocol). Volume control is planned for later.
==Advanced Configuration==
PipeWire can be extensively configured to fit the users' needs. Should the user want to do some fancy routing with null sinks, these can be defined directly in the config as shown below.
This is especially convenient if the user has a multi-channel (8+, or something "weird" like 2x2, 3x2) soundcard that keeps confusing applications with too many channels or a bad channel layout.
<strong>Note</strong>: those cards can be set to the "Pro Audio" profile with <code>pavucontrol</code> so PipeWire doesn't try to guess a wrong channel layout for them.
<syntaxHighlight lang=nix>
  services.pipewire.extraConfig.pipewire."91-null-sinks" = {
    "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";
          "priority.driver" = 8000;
        };
      }
      {
        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";
        };
      }
    ];
  };
</syntaxHighlight>
</syntaxHighlight>


Some useful knobs if you want to finetune or debug your setup:
===Linking nodes===
The config does not currently cover linking nodes together, but this can be fixed with a script. Soundcard names and ports should be replaced with the ones from the user's configuration:
<syntaxHighlight lang=bash>
#!/usr/bin/env bash
 
# ports obtained from `pw-link -io`


<syntaxHighlight lang="nix">
pw-link "Main-Output-Proxy:monitor_FL" "alsa_output.usb-Native_Instruments_Komplete_Audio_6_69BC86B9-00.pro-audio:playback_1"
services.pipewire = {
pw-link "Main-Output-Proxy:monitor_FR" "alsa_output.usb-Native_Instruments_Komplete_Audio_6_69BC86B9-00.pro-audio:playback_2"
  config.pipewire = {
 
    "context.properties" = {
pw-link "alsa_input.usb-M-Audio_Fast_Track-00.pro-audio:capture_1" "Microphone-Proxy:input_MONO"
      #"link.max-buffers" = 64;
      "link.max-buffers" = 16; # version < 3 clients can't handle more than this
      "log.level" = 2; # https://docs.pipewire.org/#Logging
      #"default.clock.rate" = 48000;
      #"default.clock.quantum" = 1024;
      #"default.clock.min-quantum" = 32;
      #"default.clock.max-quantum" = 8192;
  };
};
</syntaxHighlight>
</syntaxHighlight>
In order to load the script on startup, it can be added to <code>~/.xprofile</code> or the specific DE/WM autostart config. Similarly, a one-shot user service can be created that runs the script.


==Low-latency setup==
==Low-latency setup==
Audio production and rhythm games require lower latency audio than general applications. PipeWire can achieve the required latency with much less CPU usage compared to PulseAudio, with the appropriate configuration.
Audio production and rhythm games require lower latency audio than general applications. PipeWire can achieve the required latency with much less CPU usage compared to PulseAudio, with the appropriate configuration.
The minimum period size controls how small a buffer can be. The lower it is, the less latency there is. PipeWire has a value of 32 by default, which amounts to 1.33ms. It can be brought lower if needed:
The minimum period size controls how small a buffer can be. The lower it is, the less latency there is. PipeWire has a value of 32/48000 by default, which amounts to 0.667ms. It can be brought lower if needed:
<syntaxHighlight lang="nix">
 
services.pipewire = {
<syntaxHighlight lang=nix>
  config.pipewire = {
  services.pipewire.extraConfig.pipewire."92-low-latency" = {
     "context.properties" = {
     "context.properties" = {
       "default.clock.min-quantum" = 16 # going lower may cause crackles and distorted audio
      "default.clock.rate" = 48000;
      "default.clock.quantum" = 32;
       "default.clock.min-quantum" = 32;
      "default.clock.max-quantum" = 32;
     };
     };
   };
   };
};
</syntaxHighlight>
</syntaxHighlight>
<strong>NOTE</strong>: Every setup is different, and a lot of factors determine your final latency, like CPU speed, RT/PREEMPTIVE kernels and soundcards supporting different audio formats. That's why 32/48000 isn't always a value that's going to work for everyone. The best way to get everything working is to keep increasing the quant value until you get no crackles (underruns) or until you get audio again (in case there wasn't any). This won't guarantee the lowest possible latency, but will provide a decent one paired with stable audio.


===PulseAudio backend===
===PulseAudio backend===
Applications using the Pulse backend have a separate configuration. The default minimum value is 1024, so it needs to be tweaked if low-latency audio is desired.
Applications using the Pulse backend have a separate configuration. The default minimum value is 1024, so it needs to be tweaked if low-latency audio is desired.
<syntaxHighlight lang="nix">
 
services.pipewire = {
<syntaxhighlight lang="nix">
  config.pipewire-pulse = {
  services.pipewire.extraConfig.pipewire-pulse."92-low-latency" = {
     "context.modules" = [
     "context.properties" = [
       {
       {
         name = "libpipewire-module-protocol-pulse";
         name = "libpipewire-module-protocol-pulse";
         args = {
         args = { };
          "pulse.min.quantum" = 16; # controls minimum playback quant
       }
          "pulse.min.req" = 16; # controls minimum recording quant
          "pulse.min.frag" = 16; # controls minimum fragment size
          "server.address" = [ "unix:native" ]; # the default address of the server
        };
       };
     ];
     ];
    "pulse.properties" = {
      "pulse.min.req" = "32/48000";
      "pulse.default.req" = "32/48000";
      "pulse.max.req" = "32/48000";
      "pulse.min.quantum" = "32/48000";
      "pulse.max.quantum" = "32/48000";
    };
    "stream.properties" = {
      "node.latency" = "32/48000";
      "resample.quality" = 1;
    };
   };
   };
};
</syntaxhighlight>
</syntaxHighlight>
 
As a general rule, the values in <code>pipewire-pulse</code> should not be lower than the ones in <code>pipewire</code>.
As a general rule, the values in <code>pipewire-pulse</code> should not be lower than the ones in <code>pipewire</code>.
===Controlling the ALSA devices===
===Controlling the ALSA devices===
It is possible to configure various aspects of soundcards through <code>/etc/pipewire/media-session.d/alsa-monitor.conf</code>. Since there's no config option for it in the module, the file needs to be manually written:
It is possible to configure various aspects of soundcards through PipeWire, including format, period size and batch mode:
<syntaxHighlight lang="nix">
 
environment.etc."pipewire/media-session.d/alsa-monitor.conf".text = ''
<syntaxHighlight lang=nix>
  rules = [
  services.pipewire.wireplumber.configPackages = [
    {
    (pkgs.writeTextDir "share/wireplumber/main.lua.d/99-alsa-lowlatency.lua" ''
      matches = [ { node.name = alsa_output.* } ]
      alsa_monitor.rules = {
      actions = {
        {
        update-props = {
          matches = {{{ "node.name", "matches", "alsa_output.*" }}};
          audio.format = "S16LE"
          apply_properties = {
          audio.rate = 48000
            ["audio.format"] = "S32LE",
          api.alsa.period-size = 160 # defaults to 1024, tweak by trial-and-error
            ["audio.rate"] = "96000", -- for USB soundcards it should be twice your desired rate
          #api.alsa.disable-batch = true # generally, USB soundcards use the batch mode
            ["api.alsa.period-size"] = 2, -- defaults to 1024, tweak by trial-and-error
         }
            -- ["api.alsa.disable-batch"] = true, -- generally, USB soundcards use the batch mode
          },
         },
       }
       }
     }
     '')
   ];
   ];
'';
</syntaxHighlight>
</syntaxHighlight>
The <code>matches</code> attribute applies the <code>actions</code> to the devices/properties listed there. It is usually used with soundcard names, like shown in the config above. <code><alsa_device></code> can be one of the outputs of
 
<syntaxHighlight lang="bash">
The <code>matches</code> attribute applies the <code>actions</code> to the devices/properties listed there. It is usually used with soundcard names, like shown in the config above. <code><matches></code> can match any of the outputs of
<syntaxHighlight lang=console>
$ pw-dump | grep node.name | grep alsa
$ pw-dump | grep node.name | grep alsa
</syntaxHighlight>
</syntaxHighlight>
==Headless operation==
PipeWire can run on a headless device (without a GUI) such as a Raspberry Pi connected to a speaker. In that case, it may be preferable to start PipeWire on boot and keep it running rather than only running during an interactive login session. Among other things, this helps prevent a race condition that may occur when socket activation fails to initialize  audio devices in time for their first use, leading to one-time errors after reboots. The following additional configuration facilitates this:
<syntaxhighlight lang="nix">
  # Socket activation too slow for headless; start at boot instead.
  services.pipewire.socketActivation = false;
  # Start WirePlumber (with PipeWire) at boot.
  systemd.user.services.wireplumber.wantedBy = [ "default.target" ];
  users.users.<name>.linger = true; # keep user services running
  users.users.<name>.extraGroups = [ ... "audio" ];
</syntaxhighlight>
Despite early activation, you may still experience a race condition that prevents audio from working if you play media immediately after a new login such as running an SSH command. If this occurs, try introducing a short delay (e.g. <code>sleep 5</code>) before invoking the media player application.
==Troubleshooting==
===pactl not found===
The <code>pactl</code> functionality is superseded in PipeWire with the native <code>pw-cli</code>, <code>pw-mon</code> and <code>pw-top</code> CLI tools.
When using WirePlumber (which is enabled by default), you can also use <code>wpctl</code> as a <code>pactl</code> alternative with similar high level subcommands.
=== No signal detected in audio application from external audio interface ===
This issue was seen when attempting to use a Roland STUDIO-CAPTURE 16x10 Audio Interface to record audio in Ardour8 on NixOS. One possible solution:
* Install {{nixos:package|pavucontrol}}.
* Run {{ic|pavucontrol}}, navigate to the configuration tab, and set the Profile for STUDIO-CAPTURE (or your audio interface) to "Pro Audio".
* Ensure the audio interface and Ardour are set to the same sample rate. Ardour8 will accept a configuration where its sample rate does not match the audio interface's sample rate, when using PipeWire, but will not actually be able to record audio unless they match. If you are unable to successfully activate a track's record button, this may be the issue.
=== Sound pops a few seconds after playback stops ===
By default Wireplumber suspends a sink after 5 seconds of no playback which can create a sound pop on sensitive audio equipment. You can disable this by providing extra configuration to wireplumber but first you need to find out the name of the problematic sink in the wireplumber namespace.
<ol>
<li>'''Find out the name of the sink'''
<ol>
<li>Run <code>pw-top</code> to monitor pipewire processes</li>
<li>Play and pause sound on the problematic device. After 5 seconds the numeric columns of at least one process will disappear. This is the suspension in action. You need the value of the NAME column to refer to this sink in the configuration below. Since the display updates each second, you can't copy the value easily. Rerun <code>pw-top -b</code> and abort with <kbd>CTRL</kbd>+<kbd>C</kbd> to get persistent output.</li>
</ol>
</li>
<li>'''Add configuration''':
Assuming the value of the NAME column was <code>alsa_output.usb-ASUSTeK_Xonar_SoundCard-00.iec958-stereo</code>, add the following Nix configuration:
<syntaxhighlight lang="nix">
# Disable suspend of Toslink output to prevent audio popping.
  services.pipewire.wireplumber.extraConfig."99-disable-suspend" = {
    "monitor.alsa.rules" = [
      {
        matches = [
          {
            "node.name" = "alsa_output.usb-ASUSTeK_Xonar_SoundCard-00.iec958-stereo";
          }
        ];
        actions = {
          update-props = {
            "session.suspend-timeout-seconds" = 0;
          };
        };
      }
    ];
  };
</syntaxhighlight>
The value 0 disables suspension entirely. You could also set it to a higher value. 5 (seconds) is the default value.
</li>
<li>'''Verify resolution''':
After switching to the new configuration you need to also run <code>systemctl --user restart wireplumber</code> as your non-root user to apply the new wireplumber configuration, since wireplumber runs as your non-root user - <code>nixos-rebuild switch</code> is not sufficient. Play and pause sound again and verify that no sound pops occur anymore and observe in <code>pw-top</code> that the numeric columns for that sink do not disappear after 5 seconds.
</li>
</ol>


==See also==
==See also==
Retrieved from "https://wiki.nixos.org/wiki/PipeWire"