PulseAudio

PulseAudio is a sound server for POSIX and Win32 systems. A sound server is basically a proxy for your sound applications. It allows you to do advanced operations on your sound data as it passes between your application and your hardware. Things like transferring the audio to a different machine, changing the sample format or channel count and mixing several sounds into one are easily achieved using a sound server.

It's a drop in replacement for EsounD.

Here's how to install it, as of Dec-08-2007, on Ubuntu Gutsy Gibbon 7.10, with PulseAudio 0.9.6

Installation

Installing PulseAudio

Open a Terminal window.

Type the following:

sudo apt-get install libasound2-plugins "pulseaudio-*" paman padevchooser paprefs pavucontrol pavumeter

This will install the ALSA Pulse plugin, the PulseAudio daemons and the PulseAudio tools.

ALSA Configuration

Now, type the following:

sudo gedit /etc/asound.conf

This will open /etc/asound.conf in a Text Editor as the root user.

Normally on Ubuntu 7.10, this file will not exist, so we're creating it.

Paste in the following:

pcm.pulse {
    type pulse
}
ctl.pulse {
    type pulse
}
pcm.!default {
    type pulse
}
ctl.!default {
    type pulse
}

The top two will create new output and input definitions for PulseAudio, and the bottom two will set PulseAudio as the default audio device for programs using the ALSA interface.

Save and exit Text Editor.

Adding Users to the PulseAudio groups

Next we go to System -> Administration -> and click on Users and Groups.

Click on Manage Groups, and scroll all the way to the bottom of the list where you will find:

• pulse
• pulse-access
• pulse-rt

Make sure to highlight each, one at a time, and click Properties. Just put a check next to each user that you want to be able to have access to sound (for example, there's "ted" and "root" and "kamilion" listed, and you only want "kamilion" to have access to sound, that's the one to check, leave the other two blank)

Configuring PulseAudio

Now, go into Applications -> Sound and Video -> click on PulseAudio Preferences. * Checkmark all three options under Network Access. This will allow other computers on your LAN with PulseAudio to access this computer's sound devices. * Checkmark Enable Multicast/RTP Receiver. This allows receiving multicast streams from other systems on your LAN. * Checkmark Enable Multicast/RTP Sender. This allows sending multicast streams (One source sends packets, all others may receive them simultaneously)

Leave the other options alone for now, unless you want to loop outgoing streams through the local speakers.

Next go into System -> Preferences -> Sound and make sure that Enable Software Sound Mixing is checked. Also, under the Sounds Tab, I set devices to Autodetect.

* Reboot your machine to enable the PulseAudio server.

PulseAudio Removal

If you decide you no longer like PulseAudio and would like to disable it: Remove the added lines to /etc/asound.conf If /etc/asound.conf did not exist when you installed PulseAudio, you may remove /etc/asound.conf entirely.

After this, you may remove all of the installed PulseAudio packages.

Known Issues

Firefox/Flash and PulseAudio

Be Default, libflashplugin (Flash 9 support in Firefox) doesn't work properly with PulseAudio.

Go to http://pulseaudio.vdbonline.net/libflashsupport/ and download the deb package (as of this posting) libflashsupport_1.0~2219-1_i386.deb (9kb) and install it.

Restart Firefox to enable audio output from flash.

Firestarter & Avahi

If you have firestarter installed, it *WILL* stop PulseAudio from properly communicating over Zeroconf/Avahi's port 5353.

How to Fix:

sudo gedit /etc/firestarter/user-pre

In the file, add the following lines:

$IPT -A INPUT -p udp --dport 5353 -d 224.0.0.251 -j ACCEPT
$IPT -A OUTPUT -p udp --dport 5353 -d 224.0.0.251 -j ACCEPT

Then, save and close the file, and then type:

/etc/init.d/avahi-daemon restart

Credits

Kamilion initially wrote this wikipage on Dec-08-2007 using information found through the following sources:

Ghost|BTFH supplied the initial Ubuntu howto for older Ubuntu versions and the libflashplugin fix in his blog, here: http://ghost.thewatch.org/2007/05/pulseaudio-in-ubuntu.html

varunus supplied the information on how to make Avahi work with Firestarter here: http://ubuntuforums.org/showthread.php?t=164193