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From: Forest Denger <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Subject: /dev/dsp and multiple clients

Forgive me if this has been discussed before, but I cannot find any 
documentation on your website about it.

I am currently using KDE 2.1 and have a Creative Labs SB Live! sound card. My 
concern is for the implementation of /dev/dsp on this particular card (there 
are actually 2 other very popular chipsets made by cirrus logic and aureal 
that have these same features).

on my SB Live, I am able to allow many applications to write directly to 
/dev/dsp and it is mixed together in hardware. To my understanding, this 
dramatically offload's the cpu and does a big load of what aRts already does. 
I was wondering if there is any support for this in aRTs already, and if not, 
do you plan on adding support? I understand that most legacy sound cards do 
not support more than one audio stream, and that is the whole purpose of 
having a sound server, but in all modern day consumer level cards that are 
worth anything allow multiple audio streams to it directly, without a software 
layer.

quoted from creative lab's website FAQ:
"Features...Up to 32 simultaneous playback instances via multiple-open on 
/dev/dsp "


I believe the cirrus logic chip allows up to 64 simultaneous instances 
implemented in hardware, and more may be added with future revisions of the 
chips/drivers (they are limited to the speed of the chip, the emu10k1 is 
currently the most powerfull consumer level chip, but the drivers are somewhat 
limiting in their younger state). I believe there are good alternatives to 
using aRts along with these cards, such as allowing an app writing to 
/dev/artsdsp direct access to /dev/dsp on cards that allow it. also, you could 
use aRts to manage the extra resources of these sound cards with some nifty 
stuff.  I guess my main point is that aRts does a lot of stuff that is 
implemented in hardware on some cards, and I was wondering if aRts recognises 
these capabilities of this new hardware.

Anyway, I dont wanna ramble on anymore, so please let me know what is going on 
in these areas. I may be wrong about how the whole thing works, so please tell 
me if I am. some interesting reading would be at the creative labs sblive 
driver development website which is at: http://opensource.creative.com

____________________________________
Forest Denger
[EMAIL PROTECTED]
University of Arkansas, Fayetteville
____________________________________
-- 
  -* Stefan Westerfeld, [EMAIL PROTECTED] (PGP!), Hamburg/Germany
     KDE Developer, project infos at http://space.twc.de/~stefan/kde *-         

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