PulseAudio Tames the Linux Audio Zoo, Part 1 - page 3

Linux Audio=Herd of Cats

If your Linux audio needs are simple, stick with ALSA. It works on all Linuxes and it works just fine. If your needs are more complex, then you want to look at more complex sound servers.

PulseAudio is intended to be a drop-in replacement for ESD on Gnome. It is designed to be cross-platform, running on POSIX-compliant operating systems (like Linux), and on Win32. Before I discuss PulseAudio further, I must share an amusing true anecdote, which I promise is relevant. A good friend of mine has a number of health problems, so he spends a lot of time seeing doctors and taking a lot of medications. His favorite doctor is a Vietnamese woman with a bent sense of humor. He told her he didn't like how a certain drug was making him feel. She prescribed an additional medication. He asked why didn't she give him something to replace the nasty one, and she said "We never replace, we only add." She wasn't serious, but there was a grain of truth in it. And so it is with Linux applications and subsystems--it seems we never replace, only add.

However, PulseAudio has the potential to become the common Linux audio server, and actually replace some legacy servers like ESD and aRts. Why would we even want this? For one thing, it has a great advanced feature set:

• Individual volume controls for each playback stream
• Modular, extensible architecture
• Multiple backends for compatibility with other audio servers
• A consistent and common API
• Low-latency
• Auto-discovery of other Pulse-enabled computers on a network
• Network sound server
• Mix-and-match multiple sound devices and playback streams
• USB hotplug support
• Both GUI and command-line controls

Ubuntu Hardy users in particular are experiencing a bumpy transition to PulseAudio. It is the default sound server, but Hardy's implementation is incomplete, and there is no mention of it in the release notes. So users experiencing difficulties waste time looking for the wrong thing. Flash Player and Skype, among other popular proprietary applications, don't work with Pulse. (Isn't it funny how those big companies with paid developers can't keep up with FOSS devs.) However, all of these difficulties are being ironed out (except Ubuntu's chronically incomplete release notes), and Ubuntu Hardy users can find a lot of help on this PulseAudio Wiki page.

Next week we'll install PulseAudio on some random Linux and learn some useful and cool things to do with it, and some tips and tricks for getting past some of the bumpy parts.

Resources

• PulseAudio
• Interviews/LennartPoettering

Carla Schroder is the author of the Linux Cookbook and the newly-released Linux Networking Cookbook, and is a regular contributor to LinuxPlanet.