Rtmidi opening ports?

Question

I am working on a C++-based MIDI sending app and it's the first time I'm working with MIDI.

I chose the RtMidi library because it seems to be the most complete library around, but I'm open to suggestions.

The OS that I'm working on is Windows 7 and I have an USB-MID interface installed and it's working with other programs (i.e. Roland UM-One).

Now I may be way off-track, but I'd expect that when you do a search for ports, it should show this device.

When compiling the example code for RtMidi i get no ports; in or out.

What am I missing? Do i need to open a virtual port?

Answer 1

I've worked briefly with RtMidi and it is, as you stated, a rather complete library. However, when working with MIDI devices, you have to take the specific issues of this type of devices into account.

Another thing is that cheap USB-MIDI adapters often simply refuse to work with some applications "just because". They are very simple inside, yet apparently chinese manufacturers are still able to make malfunctioning devices.

If you're using unmodified, example code, and it's not showing your device, I'll first ensure all other apps that might be using it are closed, then try again. Creating a virtual interface is also a nice idea; I personally use freeware LoopBe1 for it. If it will show the virtual, but not the real interface, then the problem is with device itself. In that case you might want to experiment with different drivers or simply plugging it into a different port.

If it doesn't show any device, neither real nor virtual, then I strongly suspect there's something wrong in the way you build/run the application.

Answer 2

This is also for others experiencing a similar issue as well:-

When I first started using RtMIDI, if you don't specify (on OSX at least) a macro define for the target system, the example code by default uses a dummy MIDI device, and this will have no MIDI ports.

Once I had specified MAC_OSX_CORE, then RtMIDI used the correct architecture and returned the MIDI devices on my system as expected. Perhaps you have to do something similar for your system - check the docs under "Compiling":

http://www.music.mcgill.ca/~gary/rtmidi/index.html#compiling