Note: I am no longer maintaining this project. In general it seems better to use apps on Linux which can directly access MIDI devices via ALSA instead of relying on Jack.

AMidiJ can bridge ALSA (or other OS-native) MIDI ports with Jack to provide an easy interface for using native MIDI hardware from Jack applications such as REAPER, Carla and other Jack audio/MIDI applications.

It is designed as a replacement for a2jmidid which did not work well for me. The main problem with a2jmidid is that it opens all the MIDI ports on the system even when they are not being used. If you have programs that access ALSA MIDI ports directly, as well as Jack applications then this doesn't work well because the ALSA programs won't be able to open the ports when a2jmidid is running.

Instead, AMidiJ scans all the hardware ports and presents them to Jack all the time, but no ports are opened until a Jack connection is made. In a program like QjackCtl or Carla you can just drag a cable between the AMidiJ port and another application. AMidiJ will detect this and will open the MIDI port and start routing data between the port and Jack. Similarly when a connection is broken it will close the port so it can be used by another application.

Also, AMidiJ continuously scans the available hardware MIDI ports and can detect when devices are added or removed. If you plug in a MIDI device while AMidiJ is running it will instantly show up in the Jack server.

Limitations and Disclaimers:

• Only hardware MIDI ports are used. This is a limitation (at least on Linux) of the Java native MIDI interface API.

• This program has not been tested on Windows or macOS.

• This program is written in Java. Although I am quite good at C, I like doing fun projects in Java. If that's not what you're looking for, oh well.

License:

• This program is licensed under GPL 3.