From alsa-devel-owner@alsa.jcu.cz  Sat Feb 27 17:12:28 1999
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Date: Sat, 27 Feb 1999 14:29:49 +0100
From: Michele Bini <mibin@tin.it>
To: alsa-devel@alsa.jcu.cz
Cc: Kevin Duffey <kduffey@inprise.com>
Subject: Re: Instrument abstract layer
References: <3.0.32.19990225144017.0094b300@mail.inprise.com>
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In-Reply-To: <3.0.32.19990225144017.0094b300@mail.inprise.com>; from Kevin Duffey on Thu, Feb 25, 1999 at 02:40:18PM -0800
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On Thu, Feb 25, 1999 at 02:40:18PM -0800, Kevin Duffey wrote:
> All of these settings would be taken in to consideration at the user level
> (application) if the application is responsible for doing all the mixing of
> instruments, samples, etc.  The one KEY area DirectX (windows) has over
> Linux at this point is that it can use HARDWARE accelleration from
> soundcards that support that, like the SB Live, Sonic Vibes, etc. These
> cards provide drivers that DirectX uses to send the audio streams directly
> to the soundcard, allowing the soundcard to do the mixing, and relieving
> the cpu of that burden.

OSS drivers under Linux already support mixing audio streams
directly in hardware for sb AWE, SB 32 and GUS.
I don't still know if this is already supported by ALSA drivers.

> Any chance ALSA will include something like this in
> its architecture so that soundcards that can support hardware mixing will
> do that?

Please do not assume that mixing is so heavy a process even for not a
so modern CPU.
For example on my PII-233 timidity plays most midi files taking around
3% CPU time at 11 KHz, 16 bit.

-Michele

