[LAD] zita-mu1 denormals

Fons Adriaensen fons at linuxaudio.org
Wed Mar 27 11:48:29 UTC 2013

On Sun, Mar 24, 2013 at 05:18:40PM +0100, Raphaël BOLLEN wrote:

> Thanks for looking into this, I can't check for NaNs or Infs right
> now but I've tried with an output from JAAA and have the same
> result. Anyways the problem is solved with denormals protection as
> suggested by Herman.

The code was supposed to be denormal-protected without those 
patches, and I've found out why it isn't.

cmeterdsp.cc, lines 64,65 should be:

    zl += _w1 * (*pl++ - zl) + 1e-15f;
    zr += _w1 * (*pr++ - zr) + 1e-15f;

The current code uses 1e-20f as the offset. This is more than
enough to avoid denormals in the lowpass filters, but in the
following lines zl and zr are squared, and 1e-40f definitely
is denormal.

The same code is also used in jkmeter and jmeters. All will 
be updated.



A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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