HarmonyHelper

Convert MIDI files to CSV, MIDI or MP3.

Primary transformations:

• Read MIDI file, convert to MP3 (or CSV or MIDI).

Optional additional transformations:

• Remove left/right panning (useful for the next options);
• select track to highlight (increased volume);
• pan the highlighted track to the right ear;
• invert highlighting (make the highlighted track less prominent);
• convert chords into single notes by choosing either the lower or higher part of the divisi;
• add a metronome track (hihat);
• swap out the instrument for a more clear one.

This tool doesn't do anything that cannot be done with a good MIDI player, but it is very convenient.

This tool has proven useful for people practicing in a choir. They can highlight their own track (Soprano, Alt, ...) whilst also hearing the context from the other parties. The conversion to MP3 makes practicing in the car or anywhere else easy.

Usage

The HarmonyHelper has a command line and a web-interface mode.

Command line interface:

$ python3 harmonyhelper.py input.mid output.mp3
Reading file input.mid

Do you wish to remove panning?
1. yes
2. no
Your choice?
...

Web interface:

Choir MID alterations: begin

Upload your midi file here:

+-------------+  +--------+
| Choose file |  | Submit |
+-------------+  +--------+

Choir MID alterations: options
input.mid

Do you wish to remove original panning?

[ ] no
[ ] yes

...

What format should the output file have?

[ ] MIDI (.mid), the default
[ ] MP3 (.mp3), an audio file suitable for playing on various
    devices (takes up to a minute! be patient!)
[ ] CSV (.csv), a comma separated text file

+--------+
| Submit |
+--------+

Test interface:

$ RUNTESTS=1 python3 harmonyhelper.py
...
Ran n test(s) in 0.123s

Configuration

Dependencies:

• Python stdlib;
• midicsv (providing midicsv and csvmidi) for conversion between MID and CSV;
• TiMidity++ (providing timidity) for conversion to audio;
• SoX (providing sox) for simple audio post-processing and conversion to MP3.

Enabling the web interface in Apache2 should be as simple as:

<Directory "/path/to/harmonyhelper">
    <FilesMatch "^harmonyhelper[.]py$">
        Options +ExecCGI
        SetHandler cgi-script
    </FilesMatch>
</Directory>