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

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Fri Apr 24 03:22:02 UTC 2009

On Thu, 2009-04-23 at 15:36 -0500, Callum Lerwick wrote:
> On Thu, 2009-04-23 at 10:35 -0700, Fernando Lopez-Lezcano wrote:
> > 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:
> > 
> > NO.
> > 
> > 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. 
> +1
> The thing to do route Pulseaudio through Jack. Pulseaudio already has a
> Jack plugin.
> Though as pointed out, *real* pro audio people have an expensive pro
> audio card dedicated to Jack, while Pulseaudio can dink around with the
> motherboard audio and keep its damn dirty mitts off the pro card.

And Fedora, as of recent (f10?, or was that f9?), makes even _that_
difficult. The _order_ of the sound cards after a reboot is
unpredictable and is not repeatable. 

So the usual way of dealing with the "pro" card within jack does not
work (ie: on one boot hw:0 could be pointing to the motherboard card, on
the next boot it could be pointing to the "pro" card). 

The only fix AFAIK is to add a modprobe.conf that defines the order of
the cards. Easy, right? (in ancient, less civilized times, the order
would always be the same, and if you did not like it there would be an
small app that would let you configure it - that's progress :-)

-- Fernando

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