midi-parser-js
v4.0.4
Published
JSON Human readable MIDI sequences. Read from ArrayBuffers, Base64 encoded strings, or FileInput Element in Browsers.
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MidiParser.js
MidiParser is a Javascript Binary MIDI file reader for the browser and Node which converts a MIDI binary data structure to a JSON object, making it much easier to iterate over and interact with.
- Tiny and dependency free
- Browser & Node Compatible
- Supported data input :
BASE64
encoded Midi dataUINT8
arrayBuffer, obtained when reading or fetching a .mid binary.FileInput Element
in the Browser
- Custom Midi Messages
Example
A simple example parsing a MIDI file in Node ...
let midiParser = require('midi-parser-js');
let fs = require('fs')
// read a .mid binary (as base64)
fs.readFile('./test.mid', 'base64', function (err,data) {
// Parse the obtainer base64 string ...
var midiArray = midiParser.parse(data);
// done!
console.log(midiArray);
});
Example in Browser...
<script type="module">
import {MidiParser} from 'midi-parser.js'
// select the INPUT element that will handle
// the file selection.
let source = document.getElementById('filereader');
// provide the File source and a callback function
MidiParser.parse( source, function(obj){
console.log(obj);
});
</script>
<input type="file" id="filereader"/>
If you want to see it in action, you can test it Here
Syntax:
MidiParser.parse( input [, callback] );
- input : Accepts any of the supported Data Sources : FileInputElement | uint8Array | base64String
- callback : Callback to be executed when data is parsed. Only required when input is a FileInputElement
.
Handle Custom messages ( sysEx, non-standard...)
By default, the library ignores the sysEx, and non-standard messages, simply converting their values to integers (when possible). However you can provide a custom hook function to be executed when any non-standard message is found, and process it by your own, returning the resulting value.
MidiParser.customInterpreter = function( msgType, arrayBuffer, metaEventLength){ /* your code */ }
- msgType : Hex value of the message type
- arrayBuffer : Dataview of the midi data. You have to extract your value/s from it, moving the pointer as needed.
- metaEventLength : A length greater than 0 indicates a received message
If you want the default action to be executed, return false
Output JSON anatomy :
The returned JSON object contains all the attributes of the MIDI file (format type, time division, track count... ) as properties. The tracks and the MIDI events related to each track are container inside the track
property.
The following JSON object represents a MIDI file with 3 tracks and 4 events in Track 0
outputObject{
....formatType: 0|1|2, // Midi format type
....timeDivision: (int), // song tempo (bpm)
....tracks: (int), // total tracks count
....track: Array[
........[0]: Object{ // TRACK 1!
............event: Array[ // Midi events in track 1
................[0] : Object{ // EVENT 1
....................data: (string),
....................deltaTime: (int),
....................metaType: (int),
....................type: (int)
................},
................[1] : Object{...}, // EVENT 2
................[2] : Object{...}, // EVENT 3
................[3] : Object{...} // EVENT 4
............]
........},
........[1] : Object{...}, // TRACK 2
........[2] : Object{...} // TRACK 3
....]
}
If you want to read the data from Event 2 of Track 0 , you should use the following keypath :
outputObject.track[0].event[2].data;
Distribution & Installation :
The following distribution channels are available :
- NPM : Install using the following command :
$ npm install midi-parser-js -s
- GIT : You can clone the repository :
$ git clone https://github.com/colxi/midi-parser-js.git
-ZIP : Or download the package in a ZIP file from
-CDN : Include the latest release of this library in your HTML head using the CDN :
Warning : Not recommended for production enviroments!
<script src="https://colxi.info/midi-parser-js/src/main.js"></script>
Importing
This package is shipped with support to Node CommonJS and ES6 Modules. Use the appropiate method accoordintg to your enviroment.
// ES6 Module Import :
import {MidiParser} from './midi-parser.js';
// CommonJS Node Import :
let MidiParser = require('midi-parser-js');
Bonus : MIDI File Format Specifications :
MIDI Binary Encoding Specifications in https://github.com/colxi/midi-parser-js/wiki/MIDI-File-Format-Specifications