More info about jack

Neil Stevens neil at
Fri Feb 21 17:35:45 GMT 2003

Hash: SHA1

On Friday February 21, 2003 09:22, David Bishop wrote:
> > OK, looking at Jack, they say that they're low-latency and aRts isn't.
> >  If that's true, then I think aRts (especially that capital R) is
> > badly named. I hope Stefan is around and reading this thread to
> > comment on this.
> Unfortunetly, I am fairly positive it's true.  I don't think, however,
> that it is a problem for 99% of the users, for the same reason that we
> don't all need hard-realtime kernels.

Well, I'm of the opinion that everyone who uses Noatun on linux 2.4 *does* 
need Robert Love's preemption patch. :-)

> > > If arts did function as a jack host it could become the end user
> > > choice since jackd more directed toward professional users.
> >
> > Absolutely.
> >
> > So, did you want to work on this?  I can't imagine anyone would object
> > to shipping a plugin that allows the use of jack plugins.
> Dunno about using plugins, as I don't see a ton (any?) plugins for jack
> that are all that exciting.  This is a case where jackd is *not* a full
> arts replacement, as (afaict), it doesn't do any decoding for you, i.e.,
> it has no PlayObject equivalents, it expects you to decode before
> getting to it.  Or maybe I'm misunderstanding what you are saying here.

Well, the diagram on the Jack page mentions plugins in the jackd process.

> > However, I do think that an artsd-emulating jack plugin would not
> > belong in the KDE release, but rather would best fit as a separate
> > package that serves as a replacement for the regular arts releases. 
> > The only changes needed to KDE should be to the Sound Server kcontrol
> > module, to be able to choose and configure jackd instead of artsd.
> Long, long time ago (in this thread), I mentioned that if I ever get my
> current arts project done, I would look into making it so that artsd
> could use jackd as an output plugin, like it uses alsa, or oss right
> now.  So it wouldn't be a case of having a seperate jackd configuration
> module or anything, just choose it as the output.  This would allow
> someone using, say, Rosegarden to be able to use jack with it, and
> other, arts-enabled apps, at the same time.  Now, my promise to look
> into this and $1 will get you a hamburger at McDonald's, and I'm not
> expecting you to jump up and down with joy at a (relatively) nameless
> stranger talking about stuff without code. But there *is* someone
> interested in this stuff, so I wouldn't dismiss it out of hand :-)

Heh.  But what good would that do us, though, to stick yet another layer 
between arts apps and the hardware?

> *obligatory complaint*
> Um, the docs on arts really suck :-(  Maybe I'm just spoiled with the
> great Qt and KDE docs, but it's really disappointing to find that even
> the headers are poorly commented (for instance, see Arts::Refiller at
>, and based
> soley off of that (or anything else on that site), tell me what it's
> return value is supposed to represent, or what, exactly, is supposed to
> be in buffer after it returns.  I'm having to figure this stuff out by
> reading the source to other PlayObjects :-((  (thanks for the pointers
> to those, by the way.  the corrollary to the "docs suck" complaint would
> be that the mailing list is responsive)
> *end of obligatory complaint*

Right, nobody likes the arts documentation, and everyone learns by talking 
to other people and looking at other sources.

> I really like arts, I use noatun to listen to my tunes, I use the -ao
> arts option with mplayer, kmplayer in konq, kmidi to listen to my
> compositions from Rosegarden.  I'm not here to bury arts, but to praise
> it B-)

Then how about improving the aRts deficiencies instead of essentially 
giving up and outputting to jack?  :-)

- -- 
Neil Stevens - neil at
"Distinctions by race are so evil, so arbitrary and insidious that a
state bound to defend the equal protection of the laws must not allow
them in any public sphere." -- Thurgood Marshall
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