[Speex-dev] Getting at the LPC coefficients

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Fri Feb 2 14:56:35 PST 2007

> I'm interested in doing phoneme extraction, and one of the first steps in
> the algorithm I'm planning to use is to get the LPC coefficients for an
> input frame.  Since Speex is CELP-based, the coefficients must be generated
> in there somewhere.  I've tried digging around in the source code, but I'm
> finding it slow going.  Does anyone know if there's an easy way to get at
> the data?

The coefficients are generated by _spx_lpc(), but they're not stored
directly in the bit-stream. However, if you look at the beginning of the
encoder function in nb_celp.c, you'll see it's not too much trouble to
get that code.


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