[Speex-dev] memory usage

Steve Kann stevek at stevek.com
Tue Mar 1 11:17:43 PST 2005

Alfred E. Heggestad wrote:

>On Mon, 2005-02-28 at 19:42 -0500, Jean-Marc Valin wrote:
>>>jean-marc: i think we can remove spx_sig_t *orig.
>>>but am not sure about exc2Buf. is it for extension?
>>orig is already removed in SVN (which you should probably use). As for
>>exc2, it can be removed, but I'm not sure if you can just use exc
>>instead (maybe yes).
>when removing "spx_sig_t *orig;" in the encoder, the stack usage
>went from 17091 to 16451 bytes,
>I have already got a working decoder running on my Ubicom IP3K,
>using 10-15% of the CPU, with a decoder stack size of 4058 bytes.
>The encoder is next..

It will probably be very close, if you can do it.

I did a bunch of tests of encoder performance (on an Athlon XP 1700+) a 
while back, and found that, for 8kbps CBR complexity 1, I got:

(encode/decode speed)
basic compile: 29.2x / 168x

-O3 -ffast-math -funroll-all-loops
-march=pentium3 -fprefetch-loop-arrays -fsingle-precision-constant: 
53.4x / 361x

With -msse: 65x/386x

The actual numbers don't matter much, but it does mean that encoding is 
almost 6x as expensive as decoding, so expect that you're going to use 
60-90% of your CPU for speex encode..


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