Audio Unit V3 Logic Pro Losing MIDI Events

I'm seeing some strange behavior when testing the example AUv3 instrument demo in Logic Pro. If you automate the attack or release parameters the MIDI note on and off messages are sometimes lost. This occurs especially with higher I/O Buffer sizes. With 512 or 1024 as the setting many note on and note off messages are gone and notes are stuck or don't play. With lower buffer sizes or no automation the notes do play. I noticed it in my Audio Unit based off of the example. Would anyone else try it?

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I verified that this problem exists in 10.13 Beta (17A358a). My original test was using 10.12.6. Logic 10.3.2 is being used. It doesn't appear to matter whether it is in process or in a separate process.

Can someone verify the problem? It takes about 5 minutes to try.

I couldn't reproduce the note on/off issues with automated attack/release while using the Apple's sample code instrument.


However, I did take some time to create macOS AU version of my iPad synth and I found that after playing 3-4 notes Logic would stop sending MIDI events to the render loop. If I pressed play/stop in Logic the synth would start working again, but would stop after playing 3-4 notes. So not sure what to make of this. Could be related to your issue, but I'm not sure. It's unlikely that it's a bug in my code, because it works fine on iOS.


For now I'm giving up on macOS AU. Dunno if anyone has shipped AUv3 synth on the mac.

@nikoliziapps do you have sample code that shows how you are doing this