VST3 and MIDI CC pitfall

OK - thanks. Good to know that this is not a VST3 SDK issue but rather a host issue.

(I am just a beginner in coding VST plugins, maybe i have overlooked anything.)

So it was never thought of designing “real” midi VST3 plugins?

I recentley did this juce beginner tutorial: hxxps://docs.juce.com/master/tutorial_code_basic_plugin.html
(cant post links, so replace xx to tt)
VST2 version works fine upon setting plugin midi in and plugin midi out in projucer. While VST3 plugin simply doesnt work.

What is the solution to get the VST3 version working?

Also Why is it so bad to not allow 3 VST3 plugin versions? MIDI FX, Audio and Mixed aka Synth Plugin?

There is a post above that answers your question:

In other words, Steinberg, Presonus, Ableton don’t want you to create your own MIDI plugins. They want you to use their great (cough) MIDI effects instead. Now that VST2 has been deprecated, if you want to create your own MIDI effects, you have to get a Mac, code them as MIDI effect Audio Units and use them in Logic or Reaper.


I have a similar issue - I’m not trying to create a MIDI effect, just one that uses MIDI CCs for parameters (using IMidiMapping).

Steinberg’s LegacyMIDICCOutEvent workaround has caused ambiguity which actively breaks some use-cases. Here’s a diagram I posted in another thread about how MIDI is passed through an effect chain:

Effects which used IMidiMapping used to all function like (3). WithLegacyMIDICCOutEvent, it’s now ambiguous whether they should act like (5).

Any effect could output legacy MIDI events - so if they don’t, hosts have to guess whether they’re MIDI input-only, or whether they’re deliberately absorbing CCs.