mirror of
https://github.com/Tonejs/Tone.js
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82 lines
No EOL
2.3 KiB
JavaScript
82 lines
No EOL
2.3 KiB
JavaScript
/**
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* Pass in a MIDI File as the command line argument to this Node.js
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* script and it will output a js file in the same directory.
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*
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* @example
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* node MidiToScore.js mySong.mid
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*/
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var midiFileParser = require("midi-file-parser");
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var fs = require("fs");
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var file = fs.readFileSync(process.argv[2], "binary");
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var midi = midiFileParser(file);
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var output = {};
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var tempo = 120;
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var ticksPerBeat = midi.header.ticksPerBeat;
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var timeSignature = [4, 4];
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var microsecondsPerBeat = 60000000 / tempo;
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//parse the tracks
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for (var i = 0; i < midi.tracks.length; i++) {
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var data = midi.tracks[i];
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var trackName = "track"+i;
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var trackNotes = [];
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var currentTime = 0;
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for (var j = 0; j < data.length; j++) {
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//meta tag stuff
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var evnt = data[j];
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if (evnt.type === "meta"){
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if (evnt.subtype === "timeSignature"){
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timeSignature[0] = evnt.numerator;
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timeSignature[1] = evnt.denominator;
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} else if (evnt.subtype === "setTempo"){
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tempo = 60000000 / evnt.microsecondsPerBeat;
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microsecondsPerBeat = evnt.microsecondsPerBeat;
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} else if (evnt.subtype === "trackName"){
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trackName = evnt.text;
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}
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} else {
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if (evnt.subtype === "noteOn" || evnt.subtype === "noteOff"){
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currentTime += evnt.deltaTime;
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var time = deltaTimeToMeter(currentTime);
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var note = midiToNote(evnt.noteNumber);
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var velocity = evnt.velocity / 127;
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if (evnt.subtype === "noteOff"){
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velocity = 0;
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}
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trackNotes.push([time, note, velocity.toFixed(2)]);
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}
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}
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}
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output[trackName] = trackNotes;
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}
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output.tempo = tempo;
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output.timeSignature = timeSignature;
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//write it to the output file
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fs.writeFileSync(process.argv[2]+".js", JSON.stringify(output));
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function deltaTimeToMeter(deltaTime){
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var timeSigValue = timeSignature[0] / (timeSignature[1] / 4);
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// return deltaTime;
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var quarters = deltaTime / ticksPerBeat;
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var measures = Math.floor(quarters / timeSigValue);
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var sixteenths = (quarters % 1) * 4;
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quarters = Math.floor(quarters) % timeSigValue;
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var progress = [measures, quarters, sixteenths];
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return progress.join(":");
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}
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function midiToNote(noteNum){
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var noteIndexToNote = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"];
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var octave = Math.floor(noteNum / 12) - 2;
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var note = noteNum % 12;
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return noteIndexToNote[note] + octave;
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} |