Audio Setup - Pulse Bridging

For most Linux desktops, Pulseaudio is the desktop audio server and many desktop applications talk directly to Pulseaudio. JACK will take exclusive access to any device it uses as master to ensure no other application changes it's sample rate or interferes with the audio in some other way. The utility used for bridging extra devices also takes exclusive access of the device it uses. So for desktop applications to have audio while the JACK audio server is running Pulseaudio needs to be bridged to JACK. In this way, JACK acts as the "device" for Pulseaudio.

It has been found that when Pulseaudio is bridged to JACK it will cause interference if it can still see any audio hardware and so before bridging, Studio Controls will disable any ALSA modules in Pulseaudio making JACK the only audio "device" Pulseaudio sees.

Studio Controls can set up any number of pulse->JACK bridges with any number of channels. The bridging tab has two sub tabs, one for bridges from pulse to JACK and one for bridges from JACK to pulse.

The first is Pulse outputs to JACK.

This screen consists of these controls:

• Bridge to Configure is a drop down that lists all the Pulse output bridges the user has configured. This is used to select the output bridge to edit.
• Bridge Name allows changing the name of the bridge to something that better describes that bridge. The name must be unique out of all JACK clients or the auto connections will not work. Names should not have spaces or other characters that have special meaning on the command line.
• Bridge Channel Count is the number of channels this bridge should have. The channels will be labeled as 3d appropriate names
• Auto Connect Port is the first of channel count ports that this bridge should connect to. Connections are made starting at this port and continuing to channel count or the last device port which ever is less.
• Add an Output Bridge will add another Pulse to JACK bridge with the default name pulse_out-num where num is the first number that makes the JACK client name unique. The new bridge will default to two channels and no auto connections.
• Remove Output Bridge will remove the bridge displayed.

The second tab, Pulse Inputs from JACK, is the same as the first but only deals with inputs to Pulse. It has all the same settings tha work the same way with the exception that new ports will be named pulse_in-num instead.

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