Stretto

Stretto is Ruby's implementation of JFugue, an open source library originally written in Java by David Koelle for programming MIDI.

JFugue's syntax is great for producing both a human readable and parseable implementation of the MIDI specification. By detaching it from the Java sound engine, it can become an specification and be implemented in several languages/platforms. This implementation aims to be compatible with JFugue as well as serve as the basis for the format specification.

gem install stretto

require 'rubygems'
require 'stretto'

# play a scale
player = Stretto::Player.new
player.play("C D E F G A B")

# play a .jfugue file
file = File.new(File.dirname(__FILE__) + '/examples/entertainer.jfugue')
player.play(file)

Stretto currently supports the following subset of JFugue's syntax For MIDI playback:

• notes
• rests
• measures
• chords
• harmonies
• multiple voices
• melodies
• variables
• tempo changes
• channel pressure
• polyphonic pressure
• instruments
• pitch bends
• controller changes

For more on syntax, check out The Complete Guide to JFugue. The second chapter is free, and covers a good chunk of what is possible with JFugue.

Stretto uses midiator for MIDI playback. If you're running OS X, the built-in softsynth driver should just work. You can also try creating a Player with another driver, such as core_audio or alsa:

player = Stretto::Player.new(:driver => :alsa)

Stretto uses Bundler for dependency management. To run the test suite:

bundle install
rake