Hello Claude,
Simple MIDI remote control via MIDI messages (START/STOP) is already possibile. See QMidi Help:
Audio/MIDI Settings > MIDI Input > MIDI Transport
You may use the iPad App "TouchOSC" with this layout:
http://www.mixagesoftware.com/downloadables/STARTSTOP.touchosc
to send START/STOP MIDI messages to QMidi.
Relevant steps:
Configure a network session on your Mac:
https://hexler.net/docs/touchosc-setup-coremidi-networkEnable Core MIDI on TouchOSC:
https://hexler.net/docs/touchosc-configuration-connections-coremidi
Mixage Software
www.mixagesoftware.com
support@mixagesoftware.com