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Robert Schuster theBohemian at gmx.net
Tue Jun 10 18:53:18 CEST 2008


Hi,

Michael 'Mickey' Lauer schrieb:
> we have been shipping pulseaudio (which is quite a CPU hog on embedded 
> systems) on our rootfs for quite a while now. The main reason not to use alsa 
> directly was because of mixing, since alsa dmix absolutely does not cut it.
> 
> However just recently I ponder whether I should remove pulseaudio for the time 
[..]

> If we were to get rid of it, we could ditch pulseaudio and go directly to 
> alsa. This means no longer being able to mix sounds, but rather stick them 
> into a queue and play them sequentially.
> 
> Opinions?
I get the impression that it is not well understood what pulseaudio can
provide. PA is not YASS (= yet another sound server) that tries to fix
the evil 'no hw mixing available' problem. Instead it provides flexible
handling of sound sources at a very low level (lower than gstreamer I mean).

Please take a current GNU/Linux distro that ships and configures
pulseaudio in a useful way (I only know Fedora 9 and Ubuntu Hardy) and
do the following experiment:
	- start a song in your favorite media player (make sure it plays
via PA)
	- hear the music on the analog speakers that are usually connected to
your box
	- plug in a USB headset

	- surprise: the music will be played on them, too

	- unplug the headset

	- surprise 2: music app does not crash instead music can still be heard
through the analog speakers again

I have no idea how that would work with bluetooth sound devices but if
they appear as an additional ALSA device that is managed by PA it work
like with the USB case above.

Regarding CPU hogging: Lennart, PA's main developer, recently[0] wrote
about rewriting parts of PA to fix it. In short: "Especially the
power-saving features of glitch-free PA should be enough reason for the
embedded Linux people to adopt it quickly."

So if anyone on this list has no idea what to do with her/his free time.
Go hack on PA. :)

Regards
Robert

[0] - http://0pointer.de/blog/projects/pulse-glitch-free.html

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