Midi changes for upcoming Sonic Pi 3.2

WARNING this is quite a technical post. If you are new to Sonic Pi, and/or are not into using midi input then please feel free to ignore it completely. However it may be of use to those who are already using midi fairly heavily with Sonic Pi.

Just a heads up about a recent change Sam has made to the midi cue format, to bring it more into line with the way osc cues are formatted.
Instead of formats such as
new cues will now have a format like
where the device name, port number and channel which were previously in separate sections separated by the / symbol are now encoded as part of the midi header with : separators.

This has two effects, as those who are already using SP3.2dev with OSC cues will know, whereas in SP3.1 you would look to sync cues with strings like "/osc/hello" in SP3.2 because you have strings like
"/osc:" it is usally convenient to seach for a sync using "/osc*/hello" where the wild card * matches the ip address and port number which form part of the osc header.

In the same way now it will usually be convenient to use "/midi*/note_on" to match a note_on midi cue. If you want to match the channel you could use "/midi*2/note_on" to match channel 2 note_on.

Users of my programs will have come across my parse_sync_address function which I have used to extract information from both osc and midi cues, for example in my recent midifile player program.

With the new format of midi cues this needs modifying to work. I have a modified parse_midi_sync_address function which can be used to extract information from midi cues as shown below

original parse_sync_address function (still valid for osc cues)

define:parse_sync_address do |address| #gets info on wild cards used in sync address
  v= get_event(address).to_s.split(",")[6]
  if v != nil
    #return a list of address elements with wild cards substituted by actual values
    return v[3..-2].split("/")
    return ["error"]

puts parse_sync_address("/osc*/mplayer/synths/*/*")
might return ["osc:", "mplayer", "synths", "1", "4"] with the wild card * filled in by the actual trigger ing cue.

The new function

define :parse_midi_sync_address do |address|
  v= get_event(address).to_s.split(",")[6]
  if v != nil
    return p1[0].split(":")+p1[1..-1]
    return ["error"]

puts parse_midi_sync_address("/midi*/note_*")
might return
["midi", "usb_oxygen_8_v2", "1", "5", "note_on"]
filling in the missing data, but critically following the previous format for midi cues /midi/usb_oxygen_8_v2/1/5/note_on rather than the new format /midi:usb_oxygen_8_v2:1:5/note_on making it a drop in replacement when used in existing programs which are parsing midi cues.

I will post an updated midiplayer file soon.


Hi @robin.newman

which commit indtroduce this change ?


I may be incorrect, read some place that midi does not work on pi 4 / buster. If this is the case is it fixed in this release?

You are correct that the version of Sonic Pi installed on Buster which calls itself v3.1 is NOT a full version of Sonic Pi and neither supports midi or OSC.
Unfortunately Sam Aaron does not have the resources at present to build an install package for Sonic Pi 3.2, and so the only way to use it at present on a Pi4 is to build it yourself. There is no separate build package for Sonic PI 3.2 for Raspbian Buster available.

It may be possible for me to produce a downloadable bundle to work on the Pi4 under Buster, but this will not be a proper installation package.

as Sam is now self-employed funded by the support of patreon supporters, and by income for giving talks on Sonic Pi and live-coding he cannot spend the time producing a full installation package for RPi unless he can obtain extra funding for the time involved.