Hi David,

> I haven't checked out yr patch (as I am trying to stay focussed on the
> 1400 bit/s work) so I don't fully understand exactly what you have
> changed.  

No problem.

> However from reading yr posts above you are proposing changing the
> sample rate to 12.8 kHz, while keeping the frame rate constant?

Yes, the sample rate would be a local choice.

I expect better performance for high-pitch voices, but no additional
refinement on lower ones.

> I'd be
> tempted to scale some constants (e.g. N, NW, MAX_AMP & M in defines.h)
> so that they are the same length in ms at the new sample rate and see
> how that sounds on some wideband input samples.

I did not touch NW, will look into it.  I didn't change MAX_AMP in light
of not changing low-pitch voices.  I also changed P_MIN, P_MAX and... FS :)

Furthermore, I scaled the nlp_fir filter (keeping it at 600 Hz).

> I'd test the unquantised codec using c2sim at the 10ms frame rate first
> to make sure that sounds OK and nothing is broken.  You could then try
> LPC modelling with different LPC model orders.

OK, thanks.

-Rick

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