Sound

Note: at the moment sound is disabled by default so all commands must be started with the environment variable XPRA_SOUND set to any non-zero value. ie:

XPRA_SOUND=1 xpra start :10

Once the sound has started forwarding (and not before), you may get more diagnostic messages by setting XPRA_SOUND_DEBUG=1. (see Debugging)

Requirements

You will need:

• a build/installation including gstreamer support for both client and server
• a server with pulseaudio
• a client with sound output of any kind (even virtual)

Existing Desktop Test Setup

The easiest way of testing that a system is capable of forwarding and receiving sound is on a Posix system (Linux, BSD, etc) with an existing desktop environment running, and including a pulseaudio server. Check that pulseaudio is running:

pactl info

Start an xpra server:

xpra start :10

Attach from the same machine:

xpra attach

The server log file should contain the warning message:

identical pulseaudio server, refusing to create a sound loop - sound disabled

Getting this far should ensure that all the components are installed and enabled.

Test Sound Source Setup

Instead of using an existing pulseaudio server, one can use a test sound source by specifying this environment variable:

XPRA_SOUND_TEST=1 xpra start ...

This allows you to actually start the sound forwarding from the same machine and the same user account, without needing to start a new pulseaudio server. The downside is that all you will hear is a test tone. Getting this far ensures that sound forwarding does work, albeit from a fake source instead of pulseaudio.

Test Remote Setup

Using a second client machine (or a second desktop session, virtual machine, etc), we can connect this new client to the server and get the sound from the desktop session forwarded to the client. The server can be running the test source or a the desktop session's pulseaudio server. In the case of an existing pulseaudio server, simply start any sound application. pavucontrol on the server should show an Xpra entry in the Recording tab. The client should show an Xpra entry in the Playback tab (or whatever mixer/sound tool you have installed)