I have followed the instructions here to create a RPI to act as a usb midi host: https://neuma.studio/rpi-as-midi-host.html
Its great and works nicely however I would like to suppress Midi CC message 120, stop all sounds. The way I want my setup to work runs the risk of a midi loop. Everything works fine until a 120 cc message is sent, at that point it goes into a loop and crashes everything.
Is there a way to simply filter out that message to stop the loop?
I believe the pi-midi image above is using ALSA amidi and aconnect to work its magic but I don't know how i'd go about modifying the cc messages passing through.