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This is probably a question better suited for the proposed Audio Programming Q&A site, but it's still a proposal, so good ol' SO will have to do for now.

It's my understanding that:

  1. The Audio Unit standard, unlike VST, does not support plugins that generate MIDI as output.
  2. Logic (as in the industry-standard DAW for OSX) has no native support for VSTs. VST support is provided by AU wrapper plugins, such as FXpansion.

Do these together imply that one cannot have a plugin in Logic that generates MIDI data? It seems impossible, but after 20 minutes of Googling it and reading message board complaints, it appears it might very well be the case.

Or perhaps there is something outside of the AU framework?

Jeff Lee
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1 Answers1

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It definitely seems to be possible. Check out this thread on the CoreAudio mailing list, along with this post from one of the CoreAudio team members on the implemented property.

Nik Reiman
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  • Having sniffed around KVR and the Cockos forums some, it seems like AUs can generate MIDI directly through the IAC bus, i.e. they act as MIDI sources. The post from the CoreAudio team about the MIDI generation callback is both valid and yet curiously lacking in official documentation. One comment I read claimed (reliably or spuriously) that the feature was part of the API, but that no hosts support it. – Jeff Lee Jun 27 '11 at 20:09
  • That's a problem with both the AU and VST standards -- once you get a bit off the beaten path, it's likely that not every host supports it. At least it would probably work in Logic Pro, though. ;) – Nik Reiman Jun 28 '11 at 06:59