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aRts released with the KDE2.0 final beta release - current status
The development of aRts for almost one year focused now on KDE2.0 integration,
and by now, quite some things work smoothly. After switching from CORBA to
a newly developed high-speed multimedia middleware (MCOP), most of what used
to be present in aRts-0.3.4.1 had to be redone. And in fact, most of aRts
works like it should again ;).
So what does it provide? Being a component based multimedia technology, it
provides the ability to split things into small modules, which can be
recombined in any way. You can have filters, oscillators, effects, instruments,
and whatever, and plug them together.
This is used to implement a number of services.
The notification system "knotify"
... is redone from scratch in KDE2.0. You can assign to any event (such as
window close) wether it should be logged into a file, a sample should be
played, a messagebox should be popped up. Of course if a sample gets played,
it gets played via aRts. So what? Well: you can play music all the day, and
still your emails or AIM notifications will be able to play sounds.
Thats whats new against KDE1.1.2.
The sound server "artsd"
Of course, these sound notifications will simply be played back via the always
present audio server artsd. It provides things like playing samples or streams
from other applications, mixing them all together. It is network transparent.
It is based on aRts components, so it allows you to do on-server effects,
midi synthesis and all that modular magic aRts allows.
So it allows you to play quake, listen to mp3's and still hear your emails
arriving and windows moving.
So what runs with artsd right now?
- all KDE2.0 apps (more below)
- mpg123 and quake (example patches for the aRts C API)
- most OSS apps, through a wrapper application called "artsdsp" which
redirects OSS apps to aRts without them knowing
- esd compatibility can be achieved by running "artsdsp esd" (*grin*)
- there is work on OpenAL
- there is an XMMS plugin
- ... more to come... ;)
Oh yes, artsd itself should run on any hardware, given that you have working
OSS or ALSA drivers.
Configuration
As always with KDE, everything can be configured painlessly from KControl.
Simply have a look at the Sound/SoundServer, and LookNFeel/System Notifications.
The KDE media player(s) "kaiman"
Of course the KDE media player "kaiman" uses aRts. There are codecs in aRts
currently for WAV, MP3, MPG1 Video (included in KDE2.0). There are some more
experimental ones like OGG, MPG2 Video, DIVX Video.
The kaiman application itself doesn't need to do too much, as it just relies
on the services provided by aRts. That's probably why there are already two
other KDE media players available, that is noatun and kjukebox, which also
base on aRts.
This finally means that filters and decoders will be interchangeable between
them.
The control tool "artscontrol"
Well, currently, you can simply control the volume with it, as well as
insert an FFT Scope effect (which works regardless wether you are playing
quake or using kaiman, or both). It also allows you fancier things like
redirecting the output of for instance quake elsewhere (like capture to
file), but well, thats ... experimental ;), and not documented anyway.
The designer "artsbuilder"
Now thats finally the interesting part, where you can start plugging components
together to new ones in a modular way. You can use it for instance to build
instruments out of the aRts modules. Today, there are not too much modules
available, and the documentation is ... mostly non-existent (actually there
is some at arts-project.org, which is for aRts-0.3.4.1, but that is basically
the same thing).
But its cool. And it works completely on top of KDE2.0, an aRts without CORBA
and all that stuff.
More experimental: the sequencer "Brahms"
Brahms is available for KDE2.0, but not included in the release. You can
grab it from CVS (kmusic), though. It's a fully fledged sequencer which
interoperates with aRts. It works and looks mostly like CuBase, so if you
are used to this...
Yet more experimental: "artstracker"
If you used a tracker before like FastTracker, you'll know this is yet another
way of composing. It's available from CVS, and mainly used as testbed for
midi timing code.
Conclusion
aRts is cool, and it survived the transition to KDE2.0 very well (and KDE2.0
survived, too ;). For conventional soundserver use, it should be perfectly
stable. For musicians, the nice things are yet to come. It works, but still
the power aRts-0.3.4.1 offered isn't fully ported.
So simply grab KDE2.0, and play with it. Feel free to get involved. Or use
it elsewhere.
Links
- KDE2.0 final beta is available here (announcement here) - it includes all necessary aRts stuff besides the very experimental things (aRts stuff is in kdelibs, kdebase and kdemultimedia)
- technical documentation about aRts/MCOP (has also non-KDE, non-Qt, non-X11 aRts snapshots)
- the official aRts homepage
- the official KDE homepage
Feel free to send comments, code or questions to
Stefan Westerfeld
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