midimux

what is it?

midimux is a 2to1 multiplexer/router for the ALSA MIDI sequencer

why does it exist?

because csound can work with only 1 midi port at a time, so you can't use a midi controller and a midi softsynth at the same time. I needed something minimal to funnel multiple ports to multiple channels on a single port.

how does it work?

midimux, by default, creates 3 ports: MUX, DEV00 and DEV01.

• what is received on DEV00 (any channel) is sent to MUX, channel 0
• what is received on DEV01 (any channel) is sent to MUX, channel 1
• what is sent to MUX, channel 0, is sento DEV00, channel 0
• what is sent to MUX, channel 1, is sento DEV01, channel 0
• what is sent to MUX, any other channel, is discarded
• non-channel midi messages are passed unchanged

can I use multiplex more than 2 ports?

sure, just execute midimux N where N is the number of ports you need.

how do I use it?

• clone the repo
• make
• ./midimux
• use aconnect -l to find client and port number of the devices to multiplex (say $CONTROLLERCLIENT, $CONTROLLERPORT, $SYNTHCLIENT, $SYNTHPORT)
• connect midimux to your device and synth bidirectionally with:
  • aconnect midimux:1 $CONTROLLERCLIENT:$CONTROLLERPORT
  • aconnect $CONTROLLERCLIENT:$CONTROLLERPORT midimux:1
  • aconnect midimux:2 $SYNTHCLIENT:$SYNTHPORT
  • aconnect $SYNTHCLIENT:$SYNTHPORT midimux:2

now you have a port on midimux:0 with your controller and synth multiplexed. Enjoy!

how do I stop it?

good old CTRL-C

what license is it under?

GPL3

anything else?

not really.

goodbye?

goodbye.