From alsa-devel-owner@alsa.jcu.cz  Wed Nov 25 21:30:19 1998
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Date: Wed, 25 Nov 1998 14:30:04 -0600 (CST)
From: meme <meme@interzone.org>
To: alsa-devel@jcu.cz
Subject: Re: Virtual array of audio devices. Filters etc. ?
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On Wed, 25 Nov 1998, Jaroslav Kysela wrote:

> 
> PCM stream ---> Audio Server -> conversion -> filters -\
> PCM stream ---> Audio Server -> conversion -> filters ---> Kernel driver
> PCM stream ---> Audio Server -> conversion -> filters -/
> 

Mmmm...  this sounds reasonable.  The problem with Cubase VST, CoolEdit or
any other software like that is DirectX for the plugins and DSP on the
recording hardware.  I would really like to see linux as a recording
platform, even justa HD based non-linear recorder/editor.  Event
Electronics weren't willing to give me specs for their card, but I'll keep
looking into others.  Maybe Ensoniq/Emu's PARIS hardware?!  We'll see.

Fileter aren't much use to me if they aren't real-time.  This requires
(possibly) access to the DSPs while recording/mixing.  Cubase and CoolEdit
aren't necesssarily real-time either.

PCM Stream ---> Audio Server ---> DSP with filters --> conversion -->
disk.

Keep in mind that to be competitive you need to be able to have 8 24-bit
48-96Khz streams recording/aux sending/effecting at once.  PARIS does it,
but that's because there are 6 killer DSPs per PCI card.

Ideally, the implementations should be abstract enough to allow 4
soundcards to record a 4 channel mix as well as a Layla/Gine/Darla to
behave similarly addressable audio channels from the user software.

Effects need to be routable.  If I have a couple of AudioPCI cards, I need
to use my CPU to do the effects (i realize this might not be real-time,
but that's not the point at the moment)  If I have something with a DSP,
then there needs to be an abstraction layer of sorts (needs to be there
anyway, if you ask me) that can reroute the audio stream and the effect
through the DSP.  In either case, I think the architecture of the SW
should be such that it is routed through dsp /dev entries with effects
whether or not there are dsps present.

More than anything I want to be able to power up my linux box and record a
show on the HD without needing anything more than one of those LCD
displays and a keypad to set the initial level and provide a meter
readout.  hehehe.

-jkb


