Virtual Midi Output

1

Hello

I’m writing a program that can send out MIDI messages to other software, like DAWs and other audio applications. What I want to do is essentially create a virtual MIDI output for my program.

I’m currently just using the Midi Through Output, that is always available on Linux - it works just fine, I just select Midi Through as my input in my DAW as well, and it just passes it through - but I noticed that whenever I run my program, a ‘Juce Midi Output’ device shows up in my Midi device list (in my DAW), and everything I send from my app over Midi Through, is also sent over Juce Midi Output. (see image)
However, this output does not show up in the MidiOutput::getDevices() list.

This seems to be the behavior of the MidiOutput::createNewDevice() function, but I don’t call it anywhere in my code. All I’m doing right now (related to Midi) is this:

MidiOutput* midithrough = MidiOutput::openDevice(0);
if(type == 0x90)
    midithrough->sendMessageNow(MidiMessage::noteOn(channel,note,(float)velocity/127));
if(type == 0x80)
    midithrough->sendMessageNow(MidiMessage::noteOff(channel,note,(float)velocity/127));

Is it possible to get rid of the Midi Through, and directly send it out from the Juce Midi Output that is created?
Will this work on all three OSs? I read that the MidiOutput::createNewDevice() function is not available on Windows, does this have anything to do with this virtual device?

Thanks in advance
Pieter

kmidimon.png906×528 103 KB

2

Yeah, it works on OSX and Linux, but Windows just doesn’t make it possible to create a virtual device. The only way to do it is to write an actual MIDI driver and install it.

3

Thanks for the reply
This doesn’t explain, however, why the same Midi message is sent twice, over two different (virtual) output devices. Why does it do that? (Well I guess it doesn’t really matter, but it just seems a bit weird to me, especially since the same message appears on Midi Through first, and then on Juce Midi Output.)