MIDIファイルをCHUNITHM.sunaba.txtで使える音楽データに変換します。

midiToSunaba.js

var resolution = 192 // MIDIファイルの分解能 四分音符の長さ
var sunaba_spanY = 1152 // Sunabaでの一小節の長さ

var midiFileParser = require('midi-file-parser');

var file = require('fs').readFileSync('Music2.mid', 'binary')

var midi = midiFileParser(file);

var Generate = function(noteList){
	//velからattenを計算
	noteList.forEach((note, i) => {
		atten = Math.round(1000 / note.vel)
		time = Math.round(note.time / resolution / 4 * sunaba_spanY)
		console.log('addSoundNote('+note.ch+","+time+","+(note.noteNo-12)+","+atten+')')
	});
}

var noteList = [];

function Note(ch,time,noteNo,vel,duration){
	this.ch = ch
	this.time = time
	this.noteNo = noteNo
	this.vel = vel
	this.duration = duration
}

midi.tracks.forEach((trackData, i) => {
	currentNoteNo = 0
	currentVelocity = 0
	currentDeltaTime = 0
	absoluteTime = 0
	trackData.forEach((event) => {
		if(event.subtype == 'noteOn') {
			if(currentNoteNo == 0) {//ノートオフの次にノート音が来てたら
				currentNoteNo = event.noteNumber
				currentVelocity = event.velocity
				currentDeltaTime = event.deltaTime
				absoluteTime += event.deltaTime
			}
		}
		if(event.subtype == 'noteOff') {
			if(currentNoteNo == event.noteNumber) {//ちゃんとノート音の直後に来てたら
				//convertToSunaba(event.channel,absoluteTime,currentNoteNo,currentVelocity,event.deltaTime)
				noteList.push(new Note(event.channel,absoluteTime,currentNoteNo,currentVelocity,event.deltaTime));
				currentNoteNo = 0
				currentVelocity = 0
				currentDeltaTime = 0
				absoluteTime += event.deltaTime
			}
		}
	});
});
noteList.sort(function(a,b){
	return a.time - b.time;
});
Generate(noteList)