[Speex-dev] Fwd: Re: Fixed Point on wideband-mode: Single Frame loss on 2000 Hz sine causes "freak off"

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Mon Feb 1 08:29:36 PST 2010


Quoting Frank Lorenz <Frank_wtal at web.de>:

Can you look at the residual signal? i.e. what it looks like after the pitch is
removed. Any significant difference there? Also, the pitch gain can be
informative.

    Jean-Marc

> Hi Jean-Marc,
>
> dBFS means dB relative to digital full scale. In other words: a sine value of
> -42 dBFS will, on a 16 bit PCM signal, swing between 131 and -131 only (16384
> * 10^(-42/20))
> So we are far below +/-8000.
>
> At the moment, I'm out of ideas how to debug systematically. That even very
> small rounding errors alter pitch values fundamentally makes the situation
> worse for me, because it means that the huge differences in pitch between
> fixed and floating point are not neccessary part of the problem.
> Do you have some tips for me how to proceed?
>
> cheers,
> Frank
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>
>





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