Speex dev - Aug 2004 - Real time audio encoding - cpu usage

Hello Jean-Marc
>If you want to do it, I can show you
>what functions (there are 2-3) to port. Otherwise I might do it
>eventually, but it's not a top priority (there's already an SSE
version
>though).
I would indeed like to know which functions can be used to improve K6-2 
performance through 3DNow.

Cheers

Bjoern D. Rasmussen

<p><p><p>>From: Jean-Marc Valin
<jean-marc.valin@hermes.usherb.ca>
>Reply-To: speex-dev@xiph.org
>To: speex <speex-dev@xiph.org>
>CC: "Bjoern D. Rasmussen" <bjoern_rasmussen@hotmail.com>
>Subject: Re: [speex-dev] Real time audio encoding - cpu usage
>Date: Mon, 02 Dec 2002 19:54:25 -0500
>
> > I've developed a p2p voice application using Speex and I'm
looking for
>ways
> > to reduce Speex's cpu usage. My K6-2 300 MHz can't even encode
16 bit
>audio
> > at 16KHz in realtime using Speex in narrowband mode. I've tried to
lower
>the
> > quality to 2 and complexity to 2 also but it's still way too slow.
> > Which other ways are there to make encoding faster? Is there a 
>3DNow-port of
> > Speex?
>
>Well, first if you need to encode 16 kHz speech, you need to use
>wideband (narrowband is for 8 kHZ). At -w --quality 5 --comp 1 I can
>encode in real-time on my PIII 1 GHz with 5% CPU. I know that the K6-II
>x87 FPU is notoriously slow, but I didn't think it was *that* slow. The
>setting I gave you might help, otherwise a 3DNow!-port would probably
>make the code 2-3 times faster. If you want to do it, I can show you
>what functions (there are 2-3) to port. Otherwise I might do it
>eventually, but it's not a top priority (there's already an SSE
version
>though).
>
>	Jean-Marc
>
>--
>Jean-Marc Valin, M.Sc.A.
>LABORIUS (http://www.gel.usherb.ca/laborius)
>Université de Sherbrooke, Québec, Canada
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> I would indeed like to know which functions can be used to improve K6-2 
> performance through 3DNow.
The functions that would provide the most improvement for the cost
(they're very simple) are:
filters.c: filter_mem2     (N is always dividable by 8 and ord is either
8 or 10)
ltp.c:     inner_prod      (len is always dividable by 8)

to further improve, you can also do:
vq.c:      vq_nbest
filters.c: fir_mem2
filters.c: iir_mem2

Last thing, compiling with -DRELEASE will give you a small improvement
on wideband (16 kHz).

        Jean-Marc


-- 
Jean-Marc Valin, M.Sc.A.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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