PulseAudio and sound apps (was: Re: Orphaning a few packages)

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Thu Apr 23 17:35:22 UTC 2009

On Wed, 2009-04-15 at 10:22 +0200, Kevin Kofler wrote:
> Orcan Ogetbil wrote:
> > I re-orphaned portaudio. I see that it is patched to work with
> > pulseaudio, which, I think, must be banned from the surface of Earth.
> > I am not planning to maintain a package with such a patch.
> PulseAudio is the default sound solution in Fedora, so all packages using
> sound SHOULD support it.
> IMHO, we should:
> * find some solution for JACK apps to work out of the box, without
> reconfiguring PulseAudio to work on top of JACK. Maybe this involves
> running JACK on top of PulseAudio (something which currently doesn't work
> because JACK does not support non-mmap ALSA devices nor the native
> PulseAudio protocol)

I think it is clear from the thread (and I arrived to it late - I was in
LAC2009), but just in case:


That solution (Jack on top of PA) does not work not because of mmap
access requirements of Jack. It does not work because Jack and PA are
_conceptually_ different and cater to different segments of the audio
users of Fedora and other distros. 

Jack is designed for very very low latency. Jack needs access to the
hardware devices. It cannot and should not run on "top of something
else". The requirement is not capricious. It is designed that way, and
works very well. Please don't break it. 

After I don't know how many Fedora releases that incorporated
(prematurely) PA, PA and Jack developers are starting to talk to make an
audio workstation that has both installed work, let's leave them to work
things out. At least the proposed scheme is an improvement over things
just not working.

-- Fernando

> maybe this involves starting up JACK when needed and
> having it load the JACK modules into PulseAudio and rerouting running
> PulseAudio streams to JACK at runtime (which can be done without
> interrupting the PulseAudio streams - the problem with that solution is
> that it breaks support for multiple output devices, which work just fine
> when using PulseAudio directly), maybe something else, but in any case a
> solution is needed to make things just work.
> * once that's done, make it a requirement that sound MUST work with
> PulseAudio without manual configuration. PulseAudio MUST be the default in
> all sound-using applications. JACK SHOULD only be used if PulseAudio (and
> any of the compatible APIs, e.g. ALSA, ESD etc.) is not supported (and as I
> explained above, it needs to interoperate with PulseAudio more than it
> currently does). Likewise, aRts (the deprecated KDE 3 sound server) SHOULD
> only be used if outputting directly to PulseAudio is not possible.
> It makes no sense to have a sound server configured by default and then have
> assorted applications not working with it. It also makes no sense to have a
> whole set of applications (JACK-using applications) require manual
> reconfiguration of the system according to a readme file shipped with the
> jack-audio-connection-kit package to even work at all.
>         Kevin Kofler

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