This program splits takes a midi file that contains every part of a choral work (i.e. SATB) and generates practice MP3 tracks for each voice.

$ git clone https://github.com/jackkinsella/midi-to-part-mp3s
$ brew install timidity lame sox
$ pip3 install -r requirements.txt

• python3, version 3.6 or greater
• Fluidsynth - MIDI-to-WAVE converter and player.
• Lame - create mp3 files.
• SoX - mix audio files.
• mido - midi objects for python.
• music21 - music toolkit used to convert MusicXML to midi.
• A general soundfont. This must be placed within './soundfonts'. The program assumes you have Timbres of Heaven downloaded to that folder and named timbres-of-heaven.sf2. If you download an .sfark file, you can go here to convert it to ".sf2".

Gotcha: There is often a midi track for time signatures called a tempo map placed at track 0. This must be included in all solo mp3s, otherwise you'll find that a 5 minute track might be over in 1 minute.

By default, track 0 of the midi is set to time signatures, and tracks 1-4 are set to SATB respectively. These defaults are used with:

$ ./midi-to-part-mp3s /Downloads/my-midi.mid

The mp3 files will appear in the folder $ ./output.

To customize which input tracks are assigned to which voices and certain volume ratios.

usage: midi-to-part-mp3s [-h]
                         [-csts COMMON_SOLO_TRACKS [COMMON_SOLO_TRACKS ...]]
                         [-s SOPRANO] [-a ALT] [-t TENOR] [-b BASS]
                         [-iv INSTRUMENTAL_VOLUME]
                         [-i INSTRUMENTAL_ACCOMPANIMENT [INSTRUMENTAL_ACCOMPANIMENT ...]]
                         midifile_path

positional arguments:
  midifile_path

optional arguments:
  -h, --help            show this help message and exit
  -csts COMMON_SOLO_TRACKS [COMMON_SOLO_TRACKS ...], --common-solo-tracks COMMON_SOLO_TRACKS [COMMON_SOLO_TRACKS ...]
                        midi tracks that must appear in all solo mp3s e.g.
                        because they contain time signature changes
  -s SOPRANO, --soprano SOPRANO
  -a ALT, --alt ALT
  -t TENOR, --tenor TENOR
  -b BASS, --bass BASS
  -iv INSTRUMENTAL_VOLUME, --instrumental-volume INSTRUMENTAL_VOLUME
                        configure instrumental volume
  -i INSTRUMENTAL_ACCOMPANIMENT [INSTRUMENTAL_ACCOMPANIMENT ...], --instrumental-accompaniment INSTRUMENTAL_ACCOMPANIMENT [INSTRUMENTAL_ACCOMPANIMENT ...]
                        midi tracks that appear in all accompaniment mp3s e.g.
                        piano or orchestra

When developing, you probably want the python requirements to be installed in a virtual env. We assume you name this mpt_venv.

$ python3 -m venv mtp_venv
$ source mpt_venv/bin/activate
(mtp_venv) $ pip install -r requirements.txt

First install mypy $ pip3 install mypy. Now run $ mypy midi-to-part-mp3s. Or better yet, integrate mypy to your editor for inline type warnings.

First install autopep8 $ pip3 install autopep8. Now run $ autopep8 <filename>. Best include autopep8 in your editor to format the code on save automatically.

Assuming you use the virtual env run all unit tests by calling the following command:

(mtp_venv) $ python -m unittest discover -s tests/ -p 'test*.py'

• tests/fixtures/Schumann-op67-4.mid – already includes a separate tempo map. Happy case.
• tests/fixtures/Schubert-872-sanctus.mid – does not have a separate tempo map, therefore exercises our internal midi rewrite features
• tests/fixtures/Brahms-Da-unten-im-Tale.mid - Another SATB example for general testing
• tests/fixtures/Abendlied-Rheinberger.xml - MusicXML example to test conversion and SSAATTBB track generation

Start the application in development mode (will reload automatically on code changes): $ FLASK_APP=webapp/app.py FLASK_DEBUG=1 flask run

Open the url http://127.0.0.1:5000/ in a browser. Code changes will be reloaded automatically.

Install Docker (community) edition for your system

Build the docker container: docker build --tag=midi-to-part-mp3 .

Start the container (in this example publish on port 4000): docker run -p 4000:80 midi-to-part-mp3

Open the url http://127.0.0.1:4000 in a browser.