jMID.js

Welcome to the jMID.js wiki!

https://barionleg.github.io/jMID.js/

jMID.js

A javascript library for reading, manipulating, and writing MIDI files.

Setup

jMID is setup into modules. You either include all the modules with jMID.min.js or you can load modules seperately if you want to load them asyncronously. Most of the modules have dependencies on other modules so You are probably better off including all modules.

<script src="jMID.min.js"></script>

<!-- OR -->

<script src="jMID.Core.min.js" async></script>
<script src="jMID.Query.min.js" async></script>
<script src="jMID.Stream.min.js" async></script>
<script src="jMID.File.min.js" async></script>
<!-- etc... -->

Using

Decoding

You can decoded a MIDI file by passing in the binary data to the Decoder.

// Get the file contents through the File API or other means...

var decoder = new jMID.Decoder();

var midiFile = decoder.decode(myMidiFile); // Returns a jMID.File object

Notes

Notes are different from individual events. A note consists of a "noteOn" event and its corresponding "noteOff" event. Notes have their own methods for manipulation making changing note timing, length, numbers, etc... easier by adjusting the "noteOn" and "noteOff" event together.

Queries

Queries can be performed on the various MIDI data allowing chaining, similiar to jQuery. Pass your jMID.File object to the jMID.Query module.

jMID.Query(midiFile).filter("noteNumber:61"); // Return all events with note number 61

// You can also short type the query call

var jm$ = jMID.Query;

jm$(midiFile).filter("velocity>45").not("type:meta"); // All notes with a velocity greater than 45 and not of type meta

// You can even increment values

jMID.Query(midiFile).filter("noteNumber>10").increment("velocity", 25); // Raise velocity 25 of note numbers higher than 10

You can query notes instead of events by using the "notes" method.

jMID.Query(midiFile).notes().not("noteNumber:41"); // All notes not number 41

jMID.Query(midiFile).notes("velocity>60"); // All notes with velocity greater than 60

Emitting Events

Almost any class can emit events (jMID.Note, jMID.Event, jMID.Track, etc...). Binding a listener is the same as you would do in jQuery.

var track = midiFile.getTrack(i);

track.on('encodeComplete', function(param1) {
  console.log("DONE ENCODING!!!");
});

track.trigger('encodeComplete', someParam); // "DONE ENCODING!!!"
// You can also pass params through the event;

Encoding

You can encode your MIDI file after being manipulated by calling the 'encode' method or the 'base64Encode' method.

midiFile.encode(); // Returns a binary string or the midi data

midiFile.base64Encode(); // Return a base64 encoded string of the binary data

Playback

You can create timed playback of a decoded MIDI file with the Player class.

var myPlayer = new jMID.Player({
  file : midiFile
});

myPlayer.on('event', function(e) {
  // Do something with the event like send to a synthesizer or something
});

myPlayer.play();

License

MIT Licensed