Thursday, October 1, 2009

Caveats for audio in Ubuntu Karmic Beta

In the wake of the Ubuntu Karmic Beta release, here are some audio gotchas on my radar:

* Volumes being erroneously set to 0 and/or muted upon reboot/shutdown
** We'll address this in Lucid by altering how alsactl store is called. For Ubuntu, there's arguably no need to actually call alsactl restore; PulseAudio handles volume state on its own. Granted, the approach will take some fleshing out, as we need to handle Kubuntu, Xubuntu, Ubuntu Studio, ...

* Default PulseAudio behaviour causes overdriven audio due to hardware inanity
** Thanks to some wonderful (sarcasm) hardware integration, we can work around this issue by using the patch mentioned in the comment. Please note that this patch will not be turned on for Karmic, because doing so will result in a very poor user experience for many more HDA users whose hardware are not quite so craptastic.

* Internal/External microphone selection is broken for many HDA users
** Well-known upstream, being addressed for Lucid, patches too invasive for Karmic, etc.

* Extremely high CPU usage by PulseAudio with third-party applications (Skype, I'm looking at you)
** Use the PulseAudio-aware beta of Skype

Finally, last post I described populating the alsactl init database. There are a few things of which one should be aware:

* Too quiet or too loud is usually a driver (i.e., linux) bug
** We can work around this in alsa-kernel/linux, so the first place we check is linux, not alsa-utils. In the rare case it is not a driver bug, we resort to alsactl init patches.

* You can clone the upstream alsa-utils git tree and submit patches directly
** (Next post, I'll cover how to do it.)


  1. Hi, what version or package is the pulseaudio aware version of skype?

  2. Is the version of Skype hosted via Medibuntu pulseaudio-aware? It seems to be, since it's working fantastically with no set-up.