[PlanetCCRMA] dbus support for jack?

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Sun Nov 22 15:41:51 PST 2009


On Sun, 2009-11-22 at 09:16 -0800, Er wrote:
> Hi!
> 
> I've just discovered a brand new software called Ladish (http://ladish.org/) 
> which aim to save and restore jack session. I don't have to explain you how 
> helpful it is when you have to start always the same 5 application to make 
> your music.
> 
> Anyway, 
> 
> That software needs the dbus support to be enable in jack, so here's a 
> few questions : 
> 
> 1) Is there any reason why it's not set as default?

In part because it is not settled how dbus support is going to be
enabled inside jack itself. Currently dbus support is not included in
the jack source. The current implementation is a separately patched jack
released by Nedko Arnaudov. See the latest post from him (where maybe
you found out about ladi):

  http://lalists.stanford.edu/lad/2009/11/0310.html

and the response in the thread from Paul Davis as to why things are in
the state they are (not as the result of generalized hatred of dbus, as
the thread would lead you to believe):

  http://lalists.stanford.edu/lad/2009/11/0318.html

(there were many threads before on this very same subject). 

Dbus support inside jack as currently implemented makes jakc behave
differently and you can't choose at runtime whether to enable it or not,
it is something you compile in or not. 

I made the mistake of enabling dbus in jack and it caused problems for
users. I had not realized that the _behavior_ of jack had actually
changed in a non compatible way - you can't do that and not give the
option of opting in and out to users, that is impossible with the
current implementation. 

> 2) I didn't found the srpm so I can make it myself, are they available 
> somewhere?

All srpms for my packages are available in the Planet CCRMA web site,
for example for fc11:

http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/11/SRPMS/
(substitute other release numbers for previous or later versions)

The spec file has support for dbus in the form of a macro you define or
not. So it should be easy to roll your own (but I have not checked it
still works for some time and you would need to download the latest
Nedko tarball). 

If it turns out it is possible to use alternatives to enable the
peaceful coexistence of jack1 and jack2, then the same trick might be
used to also add jackdbus to the mix (as a testing ground). That would
be neat if it is never enabled by default. 

> I really think this ladish can really improve our user experience, 
> I hope it'll evolve quickly!

Something like LADI is really really needed. Improved user experience
was the promise of lash before ladi, and ladcca before lash (look them
up :-) One of the problems is that application writers have to include
support for it in their applications and you get a typical chicken and
egg problem (which one was first?)

-- Fernando




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