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maystudiosmaystudios/claude-skills/audio-to-midi/SKILL.md

audio-to-midi

Skill21 starsChanged 7 months agoMITView on GitHub

Convert MP3/WAV/FLAC audio files to MIDI (.mid) and MusicXML (.musicxml) with full music analysis. Two engines: Basic Pitch (general-purpose polyphonic) and Piano Model (high-accuracy piano, 96.7% F1). Optional Demucs stem separation. Use --engine piano for piano/keyboard music for best results. Trigger when the user wants to: transcribe audio to MIDI, convert music to sheet music/notes, extract notes from audio, get MusicXML from a recording, analyze tempo/key/chords of a song, separate stems (vocals/drums/bass) and transcribe each, or any audio-to-notation task. Also triggers for requests like "convert this MP3 to MIDI", "get the notes from this song", "what key is this song in", "transcribe this audio", "separate and transcribe stems".

The file

We split this skill into the rules it gives an agent

6 rules. About 0 are common, 1 is distinctive, and 5 are very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈1

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 5

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Stems?: Add --stems to separate vocals/drums/bass/other with Demucs first

    line 26
  2. Very specific:

    Output dir?: Use -o path or default to input file's directory

    line 27
  3. Very specific:

    Skip analysis?: Add --no-analysis if only MIDI/MusicXML needed

    line 28
  4. Very specific:

    Skip MusicXML?: Add --no-musicxml if only MIDI needed

    line 29
  5. Distinctive:

    Run the transcription script

    line 30
  6. Very specific:

    Important: Use py -3.12 (not python) to run the script.

    line 110

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Audio-to-MIDI Transcription

Convert audio files to MIDI and MusicXML with full music analysis (tempo, key, chords, dynamics, instruments).

Tool

Script: scripts/transcribe.py -- wraps Basic Pitch, Demucs, librosa, and music21. Auto-installs dependencies.

Workflow

  1. Identify the input audio file (MP3, WAV, FLAC, OGG, M4A)
  2. Determine options:
    • Stems? Add --stems to separate vocals/drums/bass/other with Demucs first
    • Output dir? Use -o path or default to input file's directory
    • Skip analysis? Add --no-analysis if only MIDI/MusicXML needed
    • Skip MusicXML? Add --no-musicxml if only MIDI needed
  3. Run the transcription script
  4. Report output files and analysis summary to user

Engines

EngineFlagBest forAccuracy
Basic Pitch--engine basic-pitch (default)Mixed/polyphonic musicGood
Piano Model--engine pianoPiano/keyboard music96.7% F1

For piano or keyboard music, always use --engine piano — it captures sustain/pedal, has far fewer ghost notes, and produces much more accurate MIDI.

Usage

# Piano music (recommended for piano/keyboard)
py -3.12 scripts/transcribe.py "piano.mp3" --engine piano

# General music (default engine: Basic Pitch)
py -3.12 scripts/transcribe.py "song.mp3"

# With stem separation (Demucs): each stem gets its own MIDI + MusicXML
py -3.12 scripts/transcribe.py "song.wav" --stems

# Custom output directory
py -3.12 scripts/transcribe.py "song.mp3" -o ./output --engine piano

# Tuning Basic Pitch sensitivity
py -3.12 scripts/transcribe.py "song.mp3" --onset-threshold 0.6 --frame-threshold 0.4

# MIDI only (skip MusicXML)
py -3.12 scripts/transcribe.py "song.mp3" --no-musicxml

# MIDI + MusicXML without analysis
py -3.12 scripts/transcribe.py "song.mp3" --no-analysis

Output Files

For input song.mp3:

  • song.mid -- MIDI file (for DAWs, notation software)
  • song.musicxml -- MusicXML (for MuseScore, Finale, Sibelius, Dorico)
  • song_analysis.json -- Full analysis (tempo, key, chords, dynamics, spectral)

With --stems, each stem produces its own MIDI + MusicXML:

  • vocals.mid, vocals.musicxml
  • drums.mid, drums.musicxml
  • bass.mid, bass.musicxml
  • other.mid, other.musicxml

Analysis Output

The _analysis.json contains:

  • tempo_bpm: Detected BPM
  • key: Detected key and mode (e.g. "A minor")
  • key_confidence: 0-1 confidence score
  • chords: Time-stamped chord progression
  • unique_chords: Deduplicated chord list
  • dynamics: Mean/max/min dB, dynamic range
  • spectral: Centroid, bandwidth, rolloff, ZCR
  • instrument_hints: Detected instrument categories

Tuning Parameters

FlagDefaultEffect
--onset-threshold0.5Higher = fewer ghost notes, may miss quiet notes
--frame-threshold0.3Higher = stricter note detection
--min-note-length58Minimum note duration in ms

For clean recordings (piano, guitar): defaults work well. For complex mixes: use --stems for best results. For percussive music: lower onset threshold to 0.3-0.4.

Dependencies

Auto-installed on first run: basic-pitch, librosa, music21, pretty_midi, numpy, onnxruntime. With --stems: also installs demucs (includes PyTorch). Requires: Python 3.12 (py -3.12), ffmpeg (for MP3 decoding).

Important: Use py -3.12 (not python) to run the script. Python 3.14 has compatibility issues with ML packages. The script auto-selects the ONNX backend for Basic Pitch (most compatible).

Supported Input Formats

MP3, WAV, FLAC, OGG, M4A, AAC, WMA

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