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List:       kde-multimedia
Subject:    Re: MCOP
From:       Stefan Westerfeld <stefan () space ! twc ! de>
Date:       1999-11-08 9:21:25
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   Hi!

On Sun, Nov 07, 1999 at 06:42:59PM -0500, Billy Biggs wrote:
> > > The TODO point "transfer layer needs to be rewritten" could translate to
> > > "aRts should come with an own IPC mechanism, which is commited to deliver
> > > high performance, multimedia transfer, QoS, etc.". That would mean not
> > > using DCOP, but - to have a name - ACOP, and try to build highspeed
> > > multimedia IPC suitable for streaming videos around, sending midi events
> > > in time, etc.
> > 
> > Well I just checked in MCOP, which should be just what we talked about.
> >
> > The problem seems to be TCP. If you profile 100000 invocations, you get
> > reported about 7 secs of CPU usage by gprof, and it takes 24 sec. I
> > assume that the rest of the performance gets lost somewhere deep down
> > in linux. (TCP packet stuff etc.)
> 
>   So, all communication is done through TCP?  What is being sent across?

If you want to know exactly, the protocol is documented in the CVS (so you'll
see each byte ;). kdemultimedia/arts/doc/MCOP.

> Is this for blasting audio fragments in hopes that they can be played just
> in time, or is there some other means of doing that?

If things go well (I think they will), it will be used for everything that
was done by CORBA before. That is e.g. communication between GUI components
and synthesis components, sending around midi events, etc.

On the other hand, I intend to do streaming over that as well, so the things
like sending your stream to aRts to play it will be MCOP. Basically, the idea
is to make all aRts objects MCOP objects (something like Synth_ADD or
Synth_PLAY_WAV), and then to allow MCOP to be network transparent, so you
can connect flow graphs which are running on whatever server.

E.g. Brahms could run some components locally (in its process), which handle
some midi processing, and in the end the resulting midi stream could be sent
to the aRts server.

But that's still lots of work ;)

>   Where is the code checked in?

In kdemultimedia/arts.

   Cu... Stefan
-- 
  -* Stefan Westerfeld, stefan@space.twc.de (PGP!), Hamburg/Germany
     KDE Developer, project infos at http://space.twc.de/~stefan/kde *-

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