From alsa-devel-owner@alsa.jcu.cz  Thu Nov 26 12:05:04 1998
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	Thu, 26 Nov 1998 11:57:15 +0100
Date: Thu, 26 Nov 1998 11:57:15 +0100 (CET)
From: Jaroslav Kysela <perex@jcu.cz>
To: Andrea Venturi <venturi@cineca.it>
cc: alsa-devel@jcu.cz
Subject: Re: Virtual array of audio devices. Filters etc. ?
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On Thu, 26 Nov 1998, Andrea Venturi wrote:

> Magnus Norddahl wrote:
> > 
> > Quoting Jaroslav Kysela (perex@jcu.cz):
> > 
> > > We have big discussion about this, but seems that user space is more
> > > reasonable for these things:
> > >
> > > PCM stream ---> Audio Server -> conversion -> filters -\
> > > PCM stream ---> Audio Server -> conversion -> filters ---> Kernel driver
> > > PCM stream ---> Audio Server -> conversion -> filters -/
> > >
> > > Kernel driver = one exclusive PCM device
> > >
> > > EsounD is way for example...
> > >
> > > Any other ideas? Comments?
> > 
> > I personally dislike the sound server daemon idea (eg. esound). This
> > requires recompilation of all the different sound applications I use. An
> > example on this is x11amp. I do not have the sourcecode to this application,
> > and therefore cannot recompile it to use esound.

This isn't very good argument - you can use all binaries with current
scheme - via exclusive PCM devices. New applications should go through
sound server... User doesn't lost any functionality.

> > Alsa would become really really cool, if several applications could open
> > /dev/dsp at once.

/dev/dsp is obsolete OSS interface for ALSA...

> i believe also that some modern audio chip like Ess Maestro II (called
> in the .pdf "audio accellerator") could mix up to 64 streams (and with
> different dac rates too!) directly in the hardware..

Yes, I'm planning extend ALSA for support up to 16 PCM devices per
soundcard in 0.3.0 for this type hardware. This way (hardware support)
seems for me much better that doing some nasty things in kernel code.
But - ALSA is open - if someone write PCM mixing module (code willn't be
trivial and probably not all applications will work with this module) -
I'm ready include this module to ALSA driver (but only as add-on module
like OSS emulation).

							Jaroslav

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic



