micromidi

A Ruby DSL for MIDI

Features

Cross-platform compatible using MRI or JRuby.
Simplified MIDI and Sysex message output
MIDI Thru, processing and custom input events
Optional shorthand for live coding

Installation

gem install micromidi

Requirements

Ruby 1.9.2+ or JRuby in 1.9 mode

Requires midi-eye, midi-message and unimidi. These should install automatically with the gem.

Usage

The following are basic examples that use unimidi inputs and outputs. (see an example here that explains selecting an output…)

require "midi"

@i = UniMIDI::Input.use(:first)
@o = UniMIDI::Output.use(:first)

This example plays some arpeggios

MIDI.using($o) do

  5.times do |oct|
    octave oct
    %w{C E G B}.each { |n| play n 0.5 }
  end

end

While running, this next example sends all input directly to the output except for notes; notes that are received are only sent to the output if their octave is between 1 and 3. Output is also printed to the console by passing in $stdout.

MIDI.using(@i, @o, $stdout) do

  thru_except :note { |msg| only(msg, :octave, (1..3)) }

  join

end

This is the same example redone using shorthand aliases

M(@i, @o) do

  te :n { |m| only(m, :oct, (1..3)) }

  j

end

Finally, here is an example that maps some MIDI Control Change messages to SysEx

MIDI.using(@i, @o) do

  *@the_map =
    [0x40, 0x7F, 0x00],
    [0x41, 0x7F, 0x00],
    [0x42, 0x7F, 0x00]

  node :roland, :model_id => 0x42, :device_id => 0x10

  receive :cc do |message|

    command @the_map[message.index - 1], message.value

  end

end

I’ve written up a few posts explaining each of the concepts used here in greater detail:

Documentation

rdoc

Author

Ari Russo <ari.russo at gmail.com>

License

Apache 2.0, See the file LICENSE