[speex-dev] patch for libspeex

Jean-Marc Valin jean-marc.valin at hermes.usherb.ca
Fri Dec 13 22:46:19 PST 2002

Le sam 14/12/2002 à 01:03, Bernard Blackham a écrit :
> I have a patch for libspeex, which optimises some of the loops in
> vq_nbest and vq_nbest_sign that speeds up encoding - my results:

Thanks for the patch. I applied it and it give me up to 15% in speed.
Doesn't seem to change the results, which is a good thing (though you
originally forgot a "used=0" in vq_nbest_sign). I'll check a thing or
two and I'll apply to CVS.

> test file: 10s wav file at 16000 Hz, mono
> encoding with wideband --quality 3, --comp 3
> machine: PIII-900Mhz, 256MB RAM
> before: 2.78s after: 2.38s

Strange... on my PIII, encoding a 10 sec file with --comp 3 --quality 3
takes less than a second (your patch is still a bit faster). How did you
get these timings?

> I'm still trying to grasp the code (I'm just a coder, no background
> in sound processing), and just optimised some loops. Should I be
> sending the patch straight to Jean-Marc? Or is here the right place?
> It's small so attached anyway for now. Patch is against CVS 14-Dec.

Sending it to the list is a good idea I think. If you want to know what
the code does... it's simply calculating the distance between an input
vector and a list of vectors (codebook) and it returns the id's of the N
closest (n-best) codebook vectors.


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

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