MidiParser.js

MidiParser is a Javascript Binary MIDI file reader for the browser and Node which converts the binary data structure to a JSON object, making it much easier to iterate over and interact with.

It accepts BASE64 encoded Midi data, or the resulting UINT8 arrayBuffer, obtained after reading a raw .mid binary. It also, can automatically handle files selected with a FileInput Element in the browser.

Syntax:

MidiParser.parse( input [, callback] );

input : Accepts any of the supported Data Sources (FileInputElement|uint8Array|base64String)
callback : Function to handle the parsed data. 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

Parsed Data 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{...},         // TRACK 2
  	[2] : Object{...},         // TRACK 3
  	// ...
  ]
}

The data from Event 12 of Track 2 can be read like this:

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

Installation :

The following methods are available to use MidiParser.js :

Include this library in your HTML head using the CDN :

https://gitcdn.link/repo/colxi/midi-parser-js/master/src/midi-parser.js

Use NPM to install the package :

$ npm install midi-parser-js

Clone the repository from GITHUB :

$ git clone https://github.com/colxi/midi-parser-js.git

MIDI File Format Specifications :

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