midi-json-parser

This module is parsing midi files into a human-readable JSON object.

This module parses a binary MIDI file and turns it into a JSON representation. This JSON representation can then be used to pass it on to the midi-player. It can of course also be modified to be encoded as binary MIDI file at some point again by using the json-midi-encoder.

Usage

This module is available on npm and can be installed by running the following command:

npm install midi-json-parser

Once the module is installed you can use its one and only function as shown in the example below:

import { parseArrayBuffer } from 'midi-json-parser';

// Let's assume there is an ArrayBuffer called arrayBuffer which contains the binary content of a
// MIDI file.

parseArrayBuffer(arrayBuffer).then((json) => {
    // json is the JSON representation of the MIDI file.
});

In case you are comfortable with TypeScript, this is the interface which describes the JSON representation:

interface IMidiFile {
    division: number;

    format: number;

    tracks: TMidiEvent[][];
}

The type TMidiEvent is a union of all possible MIDI events. Here is the complete list of all MIDI events this module can handle:

• IMidiChannelPrefixEvent
• IMidiChannelPressureEvent
• IMidiControlChangeEvent
• IMidiCopyrightNoticeEvent
• IMidiDeviceNameEvent
• IMidiEndOfTrackEvent
• IMidiInstrumentNameEvent
• IMidiKeyPressureEvent
• IMidiKeySignatureEvent
• IMidiLyricEvent
• IMidiMarkerEvent
• IMidiMidiPortEvent
• IMidiNoteOffEvent
• IMidiNoteOnEvent
• IMidiPitchBendEvent
• IMidiProgramChangeEvent
• IMidiProgramNameEvent
• IMidiSequencerSpecificEvent
• IMidiSetTempoEvent
• IMidiSmpteOffsetEvent
• IMidiSysexEvent
• IMidiTextEvent
• IMidiTimeSignatureEvent
• IMidiTrackNameEvent
• IMidiUnknownTextEvent

Acknowledgement

Developing this module wouldn't have been possible without all the great resources out there. The following list tries to mention a few of them:

• A detailed specification of the MIDI file format as HTML: Standard MIDI-File Format Spec. 1.1, updated and PDF: Standard MIDI-File Format Spec. 1.1, updated

• A brief description of the MIDI file format: Outline of the Standard MIDI File Structure

• A blog post about the timing information in MIDI files: Timing in MIDI files

• An explanation of the concept called running status: Running Status

• Actually a documentation for a Python library, but it also contains extensive information on MIDI messages itself: Mido - MIDI Objects for Python

• Very detailed information on meta messages, but also on many other non MIDI related audio topics as well: RecordingBlogs.com Wiki

• A JavaScript MIDI parser and synthesiser: jasmid - A Javascript MIDI file reader and synthesiser and its excluded parser: midi-file-parser

• A complete MIDI app which also contains a parser: MIDI.js

• A very similar parser but for Node.js only MIDI Converter

• A parser for converting MIDI into a JavaScript object which can also turn it back into a binary MIDI file again: MIDIFile