PrettyMIDI

PrettyMIDI is a simple MIDI utility library for audio applications.

Installation

$ npm install prettymidi

Interested in browser development? Check out Browserify.

Example Usage

Decoding

var fs = require('fs')
  , pm = require('pm')
  , Decoder = pm.Decoder;
 
// Decode a MIDI file, returning a pretty and easily consumable JSON object.
fs.readFile('/path/to/drums.mid', function (err, data) {
  if (err) throw err;
  var data  = new Decoder().decode(buffer);
  data.tracks[0].events.forEach(function (e) {
    console.log(e.delta); // Delta time since last MIDI event.
    switch (e.type) {
      case 'noteOn':
        mySynth.voiceOn(e.note, e.velocity);
        break;
      case 'noteOff';
        mySynth.voiceOff(e.note, e.velocity);
        break;
      default:
        break;
    }
  });
});

Web MIDI

var pm = require('prettymidi')
  , Controller = pm.Controller;
 
navigator.requestMIDIAccess().then(function (access) {
  console.log(pm.readDevices(access));
  var padKontrol = new Controller(access, 1);
  padKontrol.on('message', function (msg) {
    switch (msg.type) {
      // Message type is decoded for you
      case 'noteOn':
        console.log(msg.note);
        console.log(msg.velocity);
        break;
      ...
      case 'pitchBend':
        // Parameter names decoded depending on message type.
        console.log(msg.lowValue);
        console.log(msg.highValue);
        break;
      default:
        break;
    }
  });
}, function (message) {
  console.log('Error: ' + message);
});

Attribution

The following projects were hugely helpful and inspirational in building PrettyMIDI:

• Standard-MIDI-File-Reader
• MIDI.js.

License

Copyright (c) 2012 Nick Thompson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.