MidiInput::openDevice() not working on Windows?

1

I’m trying to get input from a midi device to a VST3 plugin. I use this pattern:

deviceManager.setMidiInputDeviceEnabled (input.identifier, true);
deviceManager.addMidiInputDeviceCallback (input.identifier, this);

This works fine on MacOS and it works fine in Reaper on Windows. However, in Ableton Live on Windows, the setMidiInputDeviceEnabled() fails. I tracked it down to a problem in MidiInput::openDevice(). This line generates a runtime exception in Live:

    wrapper.reset (MidiService::getService().createInputWrapper (*in, deviceIdentifier, *callback));

In addition, this same problem occurs in Cubase if the WinRT MIDI option in Cubase is turned off.

Does anybody have experience getting JUCE MIDI input in VST3 to work on Windows?

2

It seems to be a problem with the Win32 MidiInOpen call when the device has already been opened in the host. Apparently in that situation a plugin cannot open that same device. Since the WinRT option in Cubase doesn’t have this problem, I’m guessing this limitation has been fixed in WinRT MIDI.

3

Unfortunate that its a run time exception.

Can you modify the plugin to give an alert about the MIDI status?

I assume the host retains full MIDI control, there is no way to make changes from the plugin, only request services?

4

Yes, it’s not really a JUCE issue, but trying to connect to a midi device from a plugin on Windows is a pain. Probably the best strategy is to advise the user to take steps to make sure the host does not open a connection to the device, thus freeing it up for the plugin. It wouldn’t be easy to catch the error and display a meaningful error message since the way to workaround this would be different for every DAW.

1 Like