[Speex-dev] High CPU usage

Mark Schilling mark_schilling at gmx.de
Thu Oct 1 10:49:30 PDT 2009


Hi Mark,

the documentation (section 3.2.1) states:

"The single that will affect the CPU usage of Speex the most is whether it is compiled for floating point or fixed-point. [...] On the x86 architecture, floating-point is generally faster, but not always. "

And:

"Until the VBR feature is ported to fixed-point, you will also need to configure with –disable-vbr or define DISABLE_VBR."

So at least variable bit rate is not supported with FIXED_POINT.

Mark 

-----Original Message-----
From: speex-dev-bounces at xiph.org [mailto:speex-dev-bounces at xiph.org] On Behalf Of Mark Palkow
Sent: Wednesday, September 30, 2009 11:52 AM
To: speex-dev at xiph.org
Subject: Re: [Speex-dev] High CPU usage

We have that problem too.
Not with USB headset only. Some sound cards deliver all 0 samples when no
microphone is connected.

Using FIXED_POINT solved it. But what are the drawbacks of FIXED_POINT in
comparison to FLOATING_POINT?

Mark

-----Ursprüngliche Nachricht-----
Von: speex-dev-bounces at xiph.org [mailto:speex-dev-bounces at xiph.org] Im
Auftrag von Jozsef Vass
Gesendet: Freitag, 25. September 2009 23:43
An: mark_schilling at gmx.de
Cc: speex-dev at xiph.org
Betreff: Re: [Speex-dev] High CPU usage

I have run into the same issue. Before sending a frame to encoder, I
calculate the energy. If it is less than a small threshold, I simply replace
this frame with "silence frame," which is 320 random samples of values
smaller than 3 (16 kHz).

BTW, I have only experience this problem with certain USB headsets that
provide you all 0 samples when muted.

Jozsef



      
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