[speex-dev] Real time audio encoding - cpu usage

Jean-Marc Valin jean-marc.valin at hermes.usherb.ca
Mon Dec 2 16:54:25 PST 2002

> 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


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

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