okame / midi-parser-js

Read .mid binary files or base64 encoded MIDI data, and converts data (Tracks and Events) to Javascript structured Object .

Midi Parser Library (AKA JSMIDIPArser)

MIDIParser is a Javascript Binary MIDI files reader, for Browsers and NODEjs. Converts MIDI binary files to Javascript Structured Objects, easier to iterate and interact with.

It can also Parse BASE64 encoded .mid data, or UINT8 array data structures from a raw .mid binary.

Author URI: http://www.colxi.info/

Package distribution networks :

In browser enviroment you can include this library using the jsdelivr CDN ...

<script src='https://cdn.jsdelivr.net/gh/colxi/[email protected]/src/midi-parser.min.js'></script>

If you are in the NodeJs enviroment, can install the package via:

$ npm install midi-parser-js

Usage:

Midi-parser-js can proces MIDI data from a File input Element, or as an alternative you can provide manually the .mid file data, encoded with BASE64 or as a UINT8 Array. These are the usage options:

Autodetected Input Type:

• MIDIParser.parse( input [,CallbackFunction] ) : Accepts any of the supported Data Sources (FileInput|uint8Array|base64String) , and selects automatically the appropiate Parse method. When a FileInput element is provided, is required a callback to handle the return of the Midi Object.

FileInput DOM Element Listener (Async) :

• MIDIParser.addListener( FileInputElem , CallbackFunction ) : Sets a listener on a FileInput Element, that gets executed when the user selects a file. The listener automatically Parsess the attached .mid file and calls the provided CallbackFunction with the resulting object as first argument. ( Note: ONLY IN BROWSERS! )

Direct Encoded Data Parsing (Sync) :

• MIDIParser.Uint8( uint8Array ) : Accepts an uint8 Array as input. Returns the formatted MIDI object.

• MIDIParser.Base64( base64String ) : Accepts a Base64 String. Returns the formatted MIDI object.

Returned Object Structure :

	Output_Object{
		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
					...
				]
			},
			[1] : Object{...}
			[2] : Object{...}
			...
		]
	}

Data from Event 12 of Track 2 could be easilly readed with:

	Output_Object.track[2].event[12].data;

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MIDI File Format Specifications :

MIDI Binary Encoding Specifications in https://github.com/colxi/midi-parser-js/wiki/MIDI-File-Format-Specifications