MontyRoll

And now for something completely MIDI

MontyRoll is a lightweight and simple MIDI visualiser written in Python. It can read Standard MIDI Files and display the channels, their assigned instruments and a summary of what each one plays, and shows the notes on a scrollable, zoomable piano roll. It has no Python dependencies other than the standard library.

MontyRoll can also play the file through a synth such as timidity, if one is installed.

Requirements

• Python 3.10+ with tkinter (sudo apt install python3-tk on Debian/Ubuntu)

• Optional, for sound: a software synth on PATH, timidity recommended. See Synths for the alternatives and install commands.

Without a synth, everything except audio playback still works.

Run

python -m montyroll                            # start empty
python -m montyroll path/to/file.mid
python -m montyroll resources/chopsticks.mid   # the bundled demo

The demo is an original arrangement of Chopsticks (Euphemia Allen, 1877, public domain) generated by resources/make_demo.py: piano alone for sixteen bars, then the repeat with vibes, bass and drums, a tempo lift at the repeat and a ritardando at the end.

Features

Visualisation

• Channel strip for every channel in use:

  • colour key
  • GM instrument
  • note count
  • pitch range
  • instrument family
  • whether the part uses pitch bend

• Piano roll with:

  • per-channel colours
  • velocity-shaded notes
  • piano-key gutter
  • bar/beat grid

• Three-row header ruler:

  • seconds (tempo-aware)
  • bar numbers
  • tempo changes and markers from the file

• A file can contain any number of tempo changes. Each one is shown in the header ruler, and the seconds row stretches and compresses against the bar grid to match.

• Event list with every message decoded, with tick, seconds and bar:beat for each

• Status bar tracking the pointer in musical time, naming the note (or drum sound) under the cursor

Editor

• Add, move, resize and delete notes with the mouse (see Controls).

• Grid snap from whole notes down to 1/32, or off for free placement

• Set velocity on any selection.

• Change a channel's GM instrument and set the channel volume.

• Saving re-serialises the original tracks, so any event the editor does not understand is written back unchanged.

Listen

• Play and stop from the toolbar or Space, with a cursor that follows the file's tempo map and auto-scrolls the roll.

• Mute and solo per channel. Mute silences a channel; solo plays only the soloed channels.

• Each channel's instrument can be previewed from the channel strip, in that channel's own pitch range.

• Master volume and playback speed (25-300%), affecting playback only

• Mute, solo, volume and speed all take effect during playback, which carries on from the cursor position.

• Live readout of elapsed time, bar:beat and current tempo

Controls

Synths

MontyRoll makes no sound of its own. For playback it writes a temporary MIDI file and hands it to the first of these found on PATH:

• TiMidity++ (timidity), recommended. On Debian/Ubuntu: sudo apt install timidity.

• FluidSynth (fluidsynth), which needs a General MIDI soundfont in /usr/share/sounds/sf2, /usr/share/soundfonts or /usr/local/share/soundfonts. On Debian/Ubuntu: sudo apt install fluidsynth fluid-soundfont-gm.

• WildMIDI (wildmidi)

• aplaymidi from alsa-utils, used only when an ALSA synth port other than "Midi Through" exists. Midi Through is always present and plays nothing, so on its own it is not enough.

Licence

MIT - see LICENSE.