MIDI output from WIDI AU can be routed to any MIDI Out Device or to a built-in MIDI recorder. Audio Unit technology does not support direct MIDI output to the host, and you have to use either virtual or hardware MIDI loopback to output MIDI from WIDI AU to the host's MIDI Track.
Routing to MIDI Out Device
When midi to midi out is turned on the plugin attempts to output MIDI messages to the MIDI Output Device you choose. You can use third-party phantom MIDI devices (Virtual MIDI Cables) to route MIDI data back to the host. MacOS X includes Apple's original IAC driver that allows such routing. To use it, choose "IAC driver" as MIDI out device in WIDI AU and choose IAC as input device in your AU host program. If you use this option, MIDI messages will route from WIDI AU back to AU host through IAC driver.
The plugin allows to record MIDI with the help of the built-in MIDI recorder. MIDI file recording starts after pressing Record button on the main page of the plugin and stops on pressing Stop. In order to save recorded MIDI data to a file press Save and enter the file name.
In order to start MIDI output from WIDI AU you may need to activate IAC Bus Driver on your system. To do this, open Finder window and locate Application->Utilities->Audio MIDI Setup. Launch the utility, open MIDI Devices page and click on the IAC Driver icon. In the next dialog select the Device is online checkbox. If you need to add more than one port, click on More Information at the bottom of the dialog.