Re: [FFADO-devel] Revision 2358 to 2365

[Jonathan W. <jw...@ju...>]

Hi Phil

> I committed some works around our last discussions as revision 2358 to
> 2365.

I've had a quick look at the result.  These look good.

> There is still some work to do, especially enabling the transpose view
> of the matrix mixer. Also, I have to re-read our previous email exchange
> to see what is possibly missing. I should have some time for other fixes
> before the end of next week.

No problem - I look forward to the next steps.

> In between, there is of course a need for testing these changes,
> especially for the RME device you use to own.

Sure.  I have tested this briefly.  I like the display of the fader value
under the per-output faders - that looks good.

The biggest issue I see at present is probably due to a round-off error in
the coversion to/from dB.  In the matrix mixer, if I select "3 dB", what I
end up with in the matrix cell is 2.2 dB.  I also notice that for the RME,
which has a maximum (linear) setting of 0x8000, the matrix cells and
per-output faders insist on calling this 5.7 dB.  Along similar lines, "0
dB" maps to 0 correctly, "-3 dB" becomes -2.9 and "-20 dB" becomes
(correctly) -20.  I haven't had a chance to look at the dB mapping function
but I expect that there's a roundoff effect in there, given that the
mappings used to be fine and 6 dB was the maximum displayed in the matrix
view.

I've had a really quick look at the code and can't see any obvious reason
for the change in behaviour.

I also discovered that the more complex widget hierarchy now in use broke
the mute and invert functionality.  This was because the MixerNode's parent
was no longer the top-level MatrixMixer object, so the corresponding dBus
interface object couldn't be found via parent().  I've introduced a separate
member to keep track of this now, so any future widget changes won't upset
it.  See revision 2366.

Regards
  jonathan