26 Apr
2006
26 Apr
'06
2:52 p.m.
On Wed, Apr 26, 2006 at 11:07:23AM -0400, Dave Robillard wrote:
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
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.