PipeWire: Difference between revisions

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==

==Bluetooth Configuration==

==Graphical tools==

* 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.

* 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").

<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>

     "context.objects" = [

       {

         factory = "spa-node-factory";

         args = {

         };

       }

         factory = "adapter";

         args = {

           "node.description" = "Microphone";

         };

       }

         factory = "adapter";

         args = {

           "node.description" = "Main Output";

         };

       }

     ];

   };

</syntaxHighlight>

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 32/48000 by default, which amounts to 0.667ms. It can be brought lower if needed:

<syntaxHighlight lang=nix>

   };

</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===

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">

   };

</syntaxhighlight>

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===

It is possible to configure various aspects of soundcards through PipeWire, including format, period size and batch mode:

<syntaxHighlight lang=nix>

         },

</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><matches></code> can match any of the outputs of

$ pw-dump | grep node.name | grep alsa

</syntaxHighlight>

==Troubleshooting==