midi-parse
v0.0.12
Published
JS MIDI file parser
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Readme
midi-parse
Yet Another Javascript MidiFile Parser.
Usage
Parsing a midi file
import { MidiFile, Status, Meta } from 'midi-parse';
const fileInput = document.querySelector('#midi-file')
const eventTypes = Object.assign({}, Meta, Status)
fileInput.addEventListener('change', function() {
const reader = new FileReader()
reader.onload = e => {
/* MidFile factory expects a DataView object */
let data = new DataView(e.target.result, 0, e.target.result.byteLength)
let midiFile = MidiFile(data)
/* Midi event type field is the 8 bit value given by the spec.
One can get a human readable value using the Status (for midi messsages) and
the Meta (for meta events) constant. */
midiFile.tracks = midiFile.tracks
.map(track => {
track.events
.forEach((event) => {
event.type = Object.keys(eventTypes).find(key => eventTypes[key] === event.type)
})
return track
})
console.log(JSON.stringify(midiFile, undefined, 4))
}
reader.readAsArrayBuffer(this.files[0])
})result
{
"tracks": [
{
"events": [
{
"type": "SPECIFIC",
"data": [
4,
2,
24,
8
],
"next": 30,
"delta": 0
},
{
"type": "END_OF_TRACK",
"next": 34,
"delta": 0
}
],
"length": 12
},
{
"events": [
{
"type": "SPECIFIC",
"data": [
51,
120,
32,
79,
115,
99,
32,
35,
50,
32,
52
],
"next": 90,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 10,
"value": 64
},
"next": 94,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 7,
"value": 100
},
"next": 98,
"delta": 0
},
{
"type": "PITCH_BEND",
"b1": 0,
"b2": 0,
"next": 102,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 101,
"value": 0
},
"next": 106,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 100,
"value": 0
},
"next": 110,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 6,
"value": 12
},
"next": 114,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 10,
"value": 64
},
"next": 118,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 7,
"value": 100
},
"next": 122,
"delta": 0
},
{
"type": "PITCH_BEND",
"b1": 0,
"b2": 0,
"next": 126,
"delta": 0
},
{
"type": "PROGRAM_CHANGE",
"value": 0,
"next": 129,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 101,
"value": 0
},
"next": 133,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 100,
"value": 0
},
"next": 137,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 6,
"value": 12
},
"next": 141,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 10,
"value": 64
},
"next": 145,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 7,
"value": 100
},
"next": 149,
"delta": 0
},
{
"type": "PITCH_BEND",
"b1": 0,
"b2": 0,
"next": 153,
"delta": 0
},
{
"type": "PROGRAM_CHANGE",
"value": 0,
"next": 156,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 101,
"value": 0
},
"next": 160,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 100,
"value": 0
},
"next": 164,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 6,
"value": 12
},
"next": 168,
"delta": 0
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 10,
"value": 64
},
"next": 172,
"delta": 0
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 111
},
"next": 187,
"type": "NOTE_ON",
"delta": 0
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 0
},
"next": 191,
"type": "NOTE_OFF",
"delta": 44
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 105
},
"next": 195,
"type": "NOTE_ON",
"delta": 28
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 0
},
"next": 199,
"type": "NOTE_OFF",
"delta": 21
},
{
"data": {
"value": "A#",
"octave": 5,
"velocity": 105
},
"next": 203,
"type": "NOTE_ON",
"delta": 3
},
{
"data": {
"value": "A#",
"octave": 5,
"velocity": 0
},
"next": 207,
"type": "NOTE_OFF",
"delta": 117
},
{
"data": {
"value": "A#",
"octave": 5,
"velocity": 109
},
"next": 211,
"type": "NOTE_ON",
"delta": 3
},
{
"data": {
"value": "A",
"octave": 5,
"velocity": 101
},
"next": 215,
"type": "NOTE_ON",
"delta": 48
},
{
"data": {
"value": "A#",
"octave": 5,
"velocity": 0
},
"next": 219,
"type": "NOTE_OFF",
"delta": 5
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 84
},
"next": 223,
"type": "NOTE_ON",
"delta": 43
},
{
"data": {
"value": "A",
"octave": 5,
"velocity": 0
},
"next": 227,
"type": "NOTE_OFF",
"delta": 12
},
{
"data": {
"value": "F",
"octave": 5,
"velocity": 84
},
"next": 231,
"type": "NOTE_ON",
"delta": 36
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 0
},
"next": 235,
"type": "NOTE_OFF",
"delta": 24
},
{
"data": {
"value": "A",
"octave": 5,
"velocity": 84
},
"next": 239,
"type": "NOTE_ON",
"delta": 24
},
{
"data": {
"value": "F",
"octave": 5,
"velocity": 0
},
"next": 243,
"type": "NOTE_OFF",
"delta": 24
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 84
},
"next": 247,
"type": "NOTE_ON",
"delta": 12
},
{
"data": {
"value": "A",
"octave": 5,
"velocity": 0
},
"next": 251,
"type": "NOTE_OFF",
"delta": 36
},
{
"data": {
"value": "G",
"octave": 5,
"velocity": 0
},
"next": 256,
"type": "NOTE_OFF",
"delta": 252
},
{
"type": "CONTROL_CHANGE",
"data": {
"control": 7,
"value": 100
},
"next": 330,
"delta": 0
},
{
"type": "PITCH_BEND",
"b1": 0,
"b2": 0,
"next": 334,
"delta": 0
},
{
"type": "PROGRAM_CHANGE",
"value": 0,
"next": 337,
"delta": 0
},
{
"type": "END_OF_TRACK",
"next": 341,
"delta": 0
}
],
"length": 266
}
],
"division": 96
}The MIDI file specification
http://www.somascape.org/midi/tech/mfile.html