— Here’s the short question —
Is it possible to create a VST plugin that hosts (Ableton Live in particular) will recognize as doing only MIDI (and not audio) processing?
— The long question —
[To be clear: I’ve done just the meagerest of changes to the DemoJuceFilter VST example to try to get this to work – changing only a little of the DemoJuceFilter.cpp and JucePluginCharacteristics.h files]
I want to develop a VST plugin that Ableton Live will recognize as doing only MIDI – no audio – processing. Trouble is no matter what combination of settings I use in JucePluginCharacteristics.h I can’t seem to get it to work. I get one of two outcomes:
Ableton sees it as both an audio and a MIDI plugin. This “works” in that I can pipe the MIDI out from this plugin to an Ableton instrument in a different track but I can’t choose channels nor drop an Ableton instrument into the plugin’s track (because it thinks the main output of the plugin is audio.)
Ableton sees it as MIDI only but (it seems) the DemoJuceFilter::processBlock never gets called. (The BPM/Time Signature line in the Demo is never displayed – it’s completely blank.)
(Full discloser:  above has other problems but I’ll spare you.)
So, does anyone know the magic to get this to work? Or, conversely, is this some kind of VST limitation? Ableton Live strangeness?
I’d appreciate any clues, code, or even sympathy!