[Devel] port-props extension (rescued "extended port information" extension)

Stefano D'Angelo zanga.mail at gmail.com
Wed Nov 2 15:11:12 PDT 2011

2011/11/2 David Robillard <d at drobilla.net>:
> I rescued the "extended port information" extension from the old wiki
> dump.  It was a quasi-turtle document (bad syntax) that seemed extremely
> stale but useful, so I figured it'd be good to clean it up and keep it
> maintained with the others.

And while we're talking about this... I want to propose a few more
things that could be added:

* pprops:absoluteValue predicate: when you use lv2:sampleRate you have
no way to specify absolute values. E.g., a sine wave oscillator might
have [ lv2:portProperty lv2:sampleRate ; lv2:minimum 0.0 ; lv2:maximum
0.5 ; lv2:default [ pprops:absoluteValue 440.0 ] ] ; - I understand
this has type-related implications in RDF, so if you have better

* pprops:mute property - applied to at most one toggled control input
port to indicate a "don't produce output" parameter

* pprops:bypass property - as pprops:mute, but for bypass (audio
output = audio input)

* pprops:dryWetBalance property - applied to one (or more?) control
input port(s) to specify that is a dry/wet balance port (range 0 to
100 in %)... to make it generic we maybe need some kind of
this-audio-input-correpsonds-to-this-audio-output rdf thing (e.g.,
multi-channel mixer)?

* pprops:enableSmoothing - this is a very tricky one, it would be like
the mute/bypass properties and would indicate whether some smoothing
is applied to input parameters to avoid artifacts - maybe conflicts
with pprops:causesArtifacts?

The use for these 4 properties would be basically to avoid displaying
them and at the same time let the host better deal with such things
both on the GUI and on the audio processing side.


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