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kittenm4ster's MIDI to PICO-8 Tracker Translator

"It just works, sometimes!"


  • python 3.5

How To Use

usage: [-h] [--legato] [--staccato] [--no-fix-octaves]
                 [--no-quantize] [-t MIDI_BASE_TICKS] [-d NOTE_DURATION]
                 [--midi-offset MIDI_OFFSET] [--sfx-offset SFX_OFFSET]
                 [--pattern-offset PATTERN_OFFSET] [--no-compact]
                 [--no-trim-silence] [--waveform [WAVEFORM [WAVEFORM ...]]]
                 [--octave-shift [OCTAVE_SHIFT [OCTAVE_SHIFT ...]]]
                 [--volume-shift [VOLUME_SHIFT [VOLUME_SHIFT ...]]]
                 [--mute [MUTE [MUTE ...]]]
                 midiPath [cartPath]

positional arguments:
  midiPath              The path to the MIDI file to be translated
  cartPath              The path to PICO-8 cartridge file to be generated

optional arguments:
  -h, --help            show this help message and exit
  --legato              Disable fadeout effect at the end of any notes (even
                        repeated notes)
  --staccato            Add a fadeout effect at the end of every note
  --no-fix-octaves      Do not change octaves of tracks to keep them in PICO-8
  --no-quantize         Do not perform any quantization of note lengths
  -t MIDI_BASE_TICKS, --midi-base-ticks MIDI_BASE_TICKS
                        Override MIDI ticks per PICO-8 note setting (normally
  -d NOTE_DURATION, --note-duration NOTE_DURATION
                        Override PICO-8 note duration setting (normally auto-
                        detected from MIDI tempo)
  --midi-offset MIDI_OFFSET
                        Change the start point in the MIDI file (in # of
                        PICO-8 SFX)
  --sfx-offset SFX_OFFSET
                        Change the starting SFX slot in PICO-8
  --pattern-offset PATTERN_OFFSET
                        Change the starting music pattern slot in PICO-8
  --no-compact          Don't try to compact groups of repeated notes into
                        fewer notes played for longer (this compacting is
                        sometimes slow, so using this flag will speed up
                        processing time at the cost of possibly occupying more
                        SFXes in the PICO-8 cart)
  --no-trim-silence     Don't trim silence off the beginning
  --waveform [WAVEFORM [WAVEFORM ...]]
                        Specify which PICO-8 waveform (instrument) number to
                        use for each MIDI track
  --octave-shift [OCTAVE_SHIFT [OCTAVE_SHIFT ...]]
                        Specify the number of octaves to shift each MIDI track
  --volume-shift [VOLUME_SHIFT [VOLUME_SHIFT ...]]
                        Specify a number to add to the volume of all notes in
                        each MIDI track (volume for each note will be limited
                        to the range 1-7
  --mute [MUTE [MUTE ...]]
                        Specify whether to "mute" each MIDI track (1 = mute, 0
                        = do not mute). Notes for a muted track will be
                        excluded from the PICO-8 cartridge entirely

Please Note

MIDI format stores music in a conceptually different way than PICO-8's tracker does. Because of this fundamental difference, conversion from MIDI to PICO-8 tracker format will never be 100% perfect in all cases.

Furthermore, in order to keep the scope of this program manageable, I have chosen (at least for now) to concentrate only on conversion of a certain type of MIDI file which has the following characterstics:

  • Each "voice" should be on a different track
    • This also means that MIDI file format Type 0 (the format that puts all voices on only 1 track) is not currently supported.
  • Multiple notes should never be playing at the same time on the same track
  • The tempo should not change during the song
  • The song should have a maximum of 4 tracks playing at once
    • This program maps MIDI tracks to PICO-8 channels, so only 4 can exist at the same time. The program does dynamically (every SFX boundary) switch which 4 MIDI tracks are playing, however, to try to accomodate more tracks: if a MIDI track is silent during one (SFX-aligned) 32-note section, that track will be skipped in favor of the next higher-numbered track(s) that are currently playing notes.
  • The rhythms should be regular/quantized
    • This program will attempt to do a very basic level of quantization, but if the MIDI file has rhythms that are not very regular to begin with, the result will not be good and tracks may get out of sync.
  • It should be short enough (and/or use a low enough rhythm resolution) to fit within the 64 SFX banks of the PICO-8
    • The program will try to fit as much of the song in as it can, including re-using repeated SFXes, but it can't perform miracles.
  • It should not use any drums (channel 10)
    • Right now, any MIDI notes on channel 10 will be discarded.

TLDR: If you use a MIDI with the right characteristics, this program can and does produce a great result! If you use anything else, don't be surprised if the result is a grotesque monstrosity :)


There are probably lots of bugs! This is a thing written for fun and it should be considered to be in an "work in progress" state.

Libraries/Special Thanks

To Do List

These are things that are totally unimplemented now but that I may try to implement in the future:

  • An automatic best guess MIDI-instrument-to-PICO-8-waveform mapping table
  • Automatic combination of multiple tracks into one (in places where both are not playing notes at the same time)
  • MIDI file type 0 support
  • Drums (channel 10) support
  • Tempo changes during the song
  • Pitch-bend or other effects???
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