[linux-audio-dev] Todays "LADSPA2" update

[Steve Harris]

On Wed, Apr 26, 2006 at 11:07:23AM -0400, Dave Robillard wrote:
> > > like to protest at the continued inclusion of the "logarithmic" port
> > > hint. its totally useless. at the very least, the hint should be removed
> > > and replaced by two other hints: logarithmicE and logarithmic10. saying
> > > that something might be better viewed using a logarithmic scale really
> > > says nothing useful. a more satisfactory solution would add "dBFS" to
> > > indicate that the port contains values indicating volumetric or gain
> > > levels. something like that.
> > 
> > logarithmicE and logarithmic10 have the same effect (loge(x) = constant *
> > log10(x)). But yes, I agree, its very wierd. I'm happy to ditch that hint.
> > the only thing where it does anything like the right thing on is
> > frequency, and there it is tricky as you can't *quite* go down to 0.0, but
> > specifying how close to is a bit of a crapshoot - it generally depends on
> > the sample rate.
> > 
> > Immediatly after the spec is finished I will publish an extension that
> > does real units stuff on controls, so hosts can intelligently handle dBFS,
> > frequency and so on.
> 
> Logarithmic really can't go.  If you bind a MIDI controller to a
> frequency port (be it an oscillator or lowpass filter or whatever), it's
> almost entirely useless if you don't know to do it logarithmically.
> Same thing with GUI sliders.  This is really important for us
> using-ladspa-for-synthesis people.
> 
> I got around the 0 issue by doing the log calculation on [1..n] and
> shifting down.  Actually it even works for negative values...

But that doesnt give the desired behaviour for freuqnecy inputs, and its a
hack at best for dBs.

If you can hold out for the units extension (within 24h of the 2.0 spec,
hopefully) it will all be a lot easier.

- Steve