Installation

DEMO

Import

const { Midi } = require('@tonejs/midi')

import { Midi } from '@tonejs/midi'

<script src="https://unpkg.com/@tonejs/midi"></script>

const midi = new Midi()

Basic Example

// load a midi file in the browser
const midi = await Midi.fromUrl("path/to/midi.mid")
//the file name decoded from the first track
const name = midi.name
//get the tracks
midi.tracks.forEach(track => {
 //tracks have notes and controlChanges
 //notes are an array
 const notes = track.notes
 notes.forEach(note => {
 //note.midi, note.time, note.duration, note.name
 })
 //the control changes are an object
 //the keys are the CC number
 track.controlChanges[64]
 //they are also aliased to the CC number's common name (if it has one)
 track.controlChanges.sustain.forEach(cc => {
 // cc.ticks, cc.value, cc.time
 })
 //the track also has a channel and instrument
 //track.instrument.name
})

Format

{
 // the transport and timing data
 header: {
 name: String, // the name of the first empty track, 
 // which is usually the song name
 tempos: TempoEvent[], // the tempo, e.g. 120
 timeSignatures: TimeSignatureEvent[], // the time signature, e.g. [4, 4],
 PPQ: Number // the Pulses Per Quarter of the midi file
 // this is read only
 },
 duration: Number, // the time until the last note finishes
 // an array of midi tracks
 tracks: [
 {
 name: String, // the track name if one was given
 channel: Number, // channel
 // the ID for this channel; 9 and 10 are
 // reserved for percussion
 notes: [
 {
 midi: Number, // midi number, e.g. 60
 time: Number, // time in seconds
 ticks: Number, // time in ticks
 name: String, // note name, e.g. "C4",
 pitch: String, // the pitch class, e.g. "C",
 octave : Number, // the octave, e.g. 4
 velocity: Number, // normalized 0-1 velocity
 duration: Number, // duration in seconds between noteOn and noteOff
 }
 ],
 // midi control changes
 controlChanges: {
 // if there are control changes in the midi file
 '91': [
 {
 number: Number, // the cc number
 ticks: Number, // time in ticks
 time: Number, // time in seconds
 value: Number, // normalized 0-1
 }
 ],
 },
 instrument: { // and object representing the program change events
 number : Number, // the instrument number 0-127
 family: String, // the family of instruments, read only.
 name : String, // the name of the instrument
 percussion: Boolean, // if the instrument is a percussion instrument
 }, 
 }
 ]
}

Raw Midi Parsing

const midiData = fs.readFileSync("test.mid")
const midi = new Midi(midiData)

Encoding Midi

// create a new midi file
var midi = new Midi()
// add a track
const track = midi.addTrack()
track.addNote({
 midi : 60,
 time : 0,
 duration: 0.2
})
.addNote({
 name : 'C5',
 time : 0.3,
 duration: 0.1
})
.addCC({
 number : 64,
 value : 127,
 time : 0.2
})
 
// write the output
fs.writeFileSync("output.mid", new Buffer(midi.toArray()))

Acknowledgment