json-to-midi

json2midi is a command line tool for converting a json document into a midi file.

Usage

./json2midi --input input.json --output output.mid

Installation

1. Clone the repo

    git clone https://github.com/davidgranstrom/json-to-midi.git --recursive
   

2. Build the midifile library

    ./build-libmidifile.sh
   

3. Build json2midi executable

    make
   

If you need to rebuild the midifile library for some reason, just delete ./lib/libmidifile.a and run the ./build-libmidifile.sh script again.

Document structure

The MIDI file is parsed from a json document.

{
    bpm: 128,
    timeSig: "4/4",
    tracks: [ [track1-eventlist .. ], [track2-eventlist .. ] ],
}

tracks contains event lists, a new MIDI track will be created for each event list.
bpm will set bpm value for track 0 (meta track)
timeSig (not implemented yet)

Event types

The eventType key specifies the midi event:

• eventType
  • note
  • cc

All events are required to have an absolute time in seconds:

• absTime (inter-onset time)

note

A note event will be translated into noteOn/noteOff midi event pairs. The duration key specifies when to send the noteOff event.

• midinote (0 - 127)
• channel (default 0)
• duration (default 1 second)
• velocity (default 64)

cc

• ccVal
• ccNum

Example document

{
    "timeSig": "4/4",
    "bpm": 120,
    "tracks": [
        [
            { "eventType": "note", "absTime": 0, "duration": 1, "midinote": 60 },
            { "eventType": "note", "absTime": 1, "duration": 1, "midinote": 64 },
            { "eventType": "note", "absTime": 3, "duration": 1, "midinote": 67 },
        ],
        [
            { "eventType": "note", "absTime": 0, "duration": 3, "midinote": 60 },
        ]
    ]
}