Midi Output, Issues with Velocity and Timing

Developer VST 3 SDK
1

I’m working on a VST3 plugin that takes MIDI events from process inputEvents, changes their properties and then adds them to outputEvents. I realise not all hosts (like Ableton for example) support this, but BitWig (v5) seems to which I’m testing in. I’m having some issues though

  • I’m setting the velocity of the noteOn I’m sending to the output, but this doesn’t seem to have any effect. Even if I set it to 0, BitWig is still playing the note if I output it. I’m just using “event.noteOn.velocity = x” and then “eventListOutput->addEvent(event);” but I think I’m missing something here. Is this something not all hosts support, or am I doing it wrong?
  • I’m adjusting slightly the “sampleOffset” of the outgoing note, moving it to be slightly later. If it falls within the current samples that I’m processing I add it to the output during that pass, if it’s later, I store it and add it in a later pass. Will this work with hosts that support MIDI output? Is this the right way to do it from the VST 3 SDK perspective? I ask because I’m having some issues with this as well

Any perspective/help would be much appreciated.

2

Yes it seems to be correct from VST3 point of view… did you try with other velocity values? you could try with Cubase, output event should be handled correctly. If it works with Cubase you could contact Bitwig developers about this issue.

3

Thanks for the feedback, and good idea about trying in Cubase.

The part I’m still struggling with is understanding how the sampleOffset works for incoming and outgoing events. Say for example I just want to write out all the midi events I’m getting straight back out (as kind of a bypass), I tried this code:

const int32 count = eventListInput->getEventCount();
for (int32 i = 0; i < count; ++i) {
Event e{};
if (eventListInput->getEvent(i, e) == kResultOk) {
eventListOutput->addEvent(e);
}
}

However this seems to add some kind of delay and doesn’t play the MIDI events at the exact time they were originally scheduled for. Is this expected or am I mis-understanding how this is meant to work? In case it’s relevant I’m also returning 0 for getLatencySamples for my processor.

Edit: I guess maybe what I’m asking is: is there read-ahead, or can MIDI events being output only ever go into the next block?