MidiPlayer

A javascript class to play MIDI music directly, without plugin.

By: X. Chen
Created on: 4/1/2015
Last Modified: 4/3/2015
Github site: https://github.com/chenx/MidiPlayer

About

MIDI is a widely used music format online. However the HTML5 Audio tag supports only wav/mp3/ogg formats so far. Playing MIDI usually uses the embed tag which requires the QuickTime plugin, or deprecated tag such as bgsound in IE, but not always work.

The MidiPlayer javascript class is used to play MIDI, without any plugin. It requires a HTML5 browser: firefox, chrome, safari, opera. IE9+ may work but not tested. Firefox works the best, followed by Chrome, Safari and Opera.

Demo

See demo here.

Usage

You just need to include midi.min.js (uncompressed version: midi.js) in the head section of your html page:

<script src="javascript/midi.min.js"></script>

An alternative is to include all the files from which midi.js was made (Of course, the first way is much better):

<script src="javascript/midi/stream.js"></script>
<script src="javascript/midi/midifile.js"></script>
<script src="javascript/midi/replayer.js"></script>
<script src="javascript/midi/synth.js"></script>
<script src="javascript/midi/audio.js"></script>
<script src="javascript/midi/vbscript.js"></script>
<script src="javascript/midi/MidiPlayer.js"></script>

You also need to include da.swf in the same directory as your html file. This is needed by Safari and Opera.

For the rest, check the html source of the demo above. It's just a few lines of javascript.

Features

• Can specify these in constructor parameter list: midi, target, loop, maxLoop, end_callback.
  • midi: MIDI file path.
  • target: Target html element that this MIDI player is attached to.
  • loop: Optinoal. Whether loop the play. Value is true/false, default is false.
  • maxLoop: Optional. max number of loops to play when loop is true. Negative or 0 means infinite. Default is 1.
  • end_callback: Optional. Callback function when MIDI ends. e.g., use this to reset target button value from "stop" back to "play".
• can specify a debug div, to display debug message: setDebugDiv(debug_div_id).
• Start/stop MIDI by: start(), stop().
• If a MIDI started play, call start() again will stop and then restart from beginning.

This depends on other 5 javascript files (audio.js, midifile.js, replayer.js, stream.js, synth.js) from [2][3], which is a demo of [1]. This is related to [4].

The disadvantage of [2][3] is that it does not have control over how a MIDI file is played: when clicking on the link more than once the file will be started multiple times and sounds chaotic; and there is no loop feature. Both are well handled by MidiPlayer.js here.

Another midi player javascript is in [5], but it cannot play multiple MIDI files at the same time, cannot play a MIDI file automatically after loading the page, and has no loop feature. All are handled by MidiPlayer.js here.

It can be a good idea to add MIDI support to HTML5 Audio tag, because MIDI files have much smaller size than wav/mp3, and the sound effects are very rich. Besides there is a large repertoire of MIDI music online.

To-Do

IE support, like how [5] does.

References

[1] http://matt.west.co.tt/music/jasmid-midi-synthesis-with-javascript-and-html5-audio/
[2] http://jsspeccy.zxdemo.org/jasmid/
[3] https://github.com/gasman/jasmid
[4] MIDI.js - Sequencing in Javascript.
[5] MIDI.js - The 100% JavaScript MIDI Player using W3C Web Audio
[6] Dynamically generating MIDI in JavaScript