Crate music21_rs 

Music theory analysis in Rust, ported from Python’s music21.

The crate covers the analysis side of music21: pitches, intervals, chords, keys, scales, roman numerals, chord symbols, figured bass, durations, meters, tone rows, sieves, tempo marks and voice leading. It keeps music21’s data model and gives music21’s answers, so a chord is named, a numeral realized and a scale spelled the way music21 does it. Beyond music21, it has tuning systems, regular temperaments and polyrhythms.

use music21_rs::Chord;

let chord: Chord = "C E- G B-".parse()?;
assert_eq!(chord.pitched_common_name(), "C-minor seventh chord");
assert_eq!(chord.forte_class().as_deref(), Some("4-26"));
assert_eq!(chord.chord_symbol().as_deref(), Some("Cm7"));

The main types are re-exported at the crate root; each module holds the rest of its area. Every fallible call returns the crate-wide Result.

Features

No features are on by default.

• serde derives Serialize and Deserialize for the public types.
• scala-archive bundles the Scala scale archive (about 4,000 .scl files, roughly 1 MB) and enables ScalaArchive::bundled().
• language-detection bundles music21’s excerpts in seven languages (about 1.9 MB) and enables features::language and music21’s language feature, TX1, among the native extractors.
• musicxml reads and writes MusicXML (musicxml::from_musicxml, musicxml::to_musicxml).
• musescore runs an installed MuseScore to read and write the formats it opens and saves; it turns on musicxml. MuseScore’s own .mscx is read without it, by musescore::from_mscx.

Re-exports

pub use abc::abc_chord;

pub use abc::abc_duration;

pub use abc::abc_note;

pub use abc::abc_rest;

pub use abc::pitch_name_from_abc_note;

pub use abc::pitch_names_from_abc_chord;

pub use analysis::KeyEstimate;

pub use analysis::KeyProfile;

pub use analysis::estimate_key_from_chords;

pub use analysis::estimate_key_from_chords_with;

pub use analysis::estimate_key_from_pitches;

pub use analysis::estimate_key_from_pitches_with;

pub use analysis::tonal_certainty;

pub use analysis::tonal_certainty_from_scores;

pub use articulations::Articulation;

pub use articulations::ArticulationKind;

pub use bar::Barline;

pub use bar::BarlineType;

pub use bar::Ending;

pub use bar::RepeatDirection;

pub use chord::Chord;

pub use chord::ChordResolutionSuggestion;

pub use chord::ChordTableAddress;

pub use chord::GuitarFingering;

pub use chord::GuitarStringFingering;

pub use chord::GuitarTuning;

pub use chord::GuitarTuningString;

pub use chord::IntoNotes;

pub use chord::KnownChordType;

pub use chord::TriadQuality;

pub use chord::format_vector_string;

pub use chordsymbol::ChordAlteration;

pub use chordsymbol::ChordQuality;

pub use chordsymbol::ChordStepModification;

pub use chordsymbol::ChordStepModificationType;

pub use chordsymbol::ChordSymbol;

pub use chordsymbol::Music21ChordType;

pub use chordsymbol::chord_symbol_figure_from_chord;

pub use chordsymbol::chord_symbol_from_chord;

pub use chordsymbol::known_chord_symbol_types;

pub use chordsymbol::realize_chord_symbol_durations;

pub use clef::Clef;

pub use clef::ClefKind;

pub use duration::Duration;

pub use duration::DurationTuple;

pub use duration::DurationType;

pub use duration::Grace;

pub use duration::Tuplet;

pub use duration::TupletBracket;

pub use duration::TupletShow;

pub use duration::TupletType;

pub use duration::quarter_length_to_closest_type;

pub use dynamics::Dynamic;

pub use error::Error;

pub use error::Result;

pub use instrument::Instrument;

pub use instrument::SearchLanguage;

pub use instrument::ensemble_name_by_size;

pub use interval::ChromaticInterval;

pub use interval::DiatonicInterval;

pub use interval::GenericInterval;

pub use interval::Interval;

pub use interval::IntervalDirection;

pub use interval::Specifier;

pub use interval::absolute_higher_pitch;

pub use interval::absolute_lower_pitch;

pub use interval::convert_diatonic_number_to_step;

pub use interval::convert_generic;

pub use interval::convert_semitone_to_specifier_generic;

pub use interval::convert_semitone_to_specifier_generic_microtone;

pub use interval::intervals_to_diatonic;

pub use interval::notes_to_chromatic;

pub use interval::notes_to_generic;

pub use interval::parse_specifier;

pub use interval::staff_distance_to_generic_number;

pub use interval::written_higher_pitch;

pub use interval::written_lower_pitch;

pub use key::Key;

pub use key::KeySignature;

pub use key::convert_key_string_to_music21_key_string;

pub use metadata::Metadata;

pub use metadata::MetadataValue;

pub use meter::BeamedNote;

pub use meter::BeatDivision;

pub use meter::MeterTerminal;

pub use meter::OffsetAlign;

pub use meter::TimeSignature;

pub use midi::DEFAULT_TICKS_PER_QUARTER;

pub use midi::MidiNote;

pub use midi::midi_notes_from_stream;

pub use midi::read_midi_bytes;

pub use midi::read_midi_bytes_with_tempo;

pub use midi::stream_from_midi_notes;

pub use midi::write_midi_bytes;

pub use notation::Beam;

pub use notation::BeamDirection;

pub use notation::BeamType;

pub use notation::Beams;

pub use notation::Justification;

pub use notation::Lyric;

pub use notation::NoteSize;

pub use notation::Notehead;

pub use notation::Placement;

pub use notation::StemDirection;

pub use notation::Syllabic;

pub use notation::Tie;

pub use notation::TieStyle;

pub use notation::TieType;

pub use note::IntoNote;

pub use note::Note;

pub use percussion::PercussionChord;

pub use percussion::PercussionNote;

pub use percussion::Unpitched;

pub use pitch::Accidental;

pub use pitch::AccidentalAttribute;

pub use pitch::AccidentalDisplayOptions;

pub use pitch::AccidentalSpecifier;

pub use pitch::CHROMATIC_PITCH_CLASS_NAMES;

pub use pitch::Microtone;

pub use pitch::MicrotoneSpecifier;

pub use pitch::Pitch;

pub use pitch::PitchClass;

pub use pitch::PitchClassSpecifier;

pub use pitch::PitchName;

pub use pitch::PitchOptions;

pub use pitch::convert_pitch_class_to_str;

pub use pitch::dissonance_score;

pub use pitch::pitch_class_name;

pub use pitch::simplify_multiple_enharmonics;

pub use polyrhythm::Polyrhythm;

pub use polyrhythm::PolyrhythmAnalysis;

pub use polyrhythm::PolyrhythmEvent;

pub use polyrhythm::PolyrhythmRatioTone;

pub use repeat::RepeatExpression;

pub use repeat::RepeatExpressionKind;

pub use rest::Rest;

pub use roman::roman_numeral_from_chord;

pub use roman::ImpliedQuality;

pub use roman::Minor67Default;

pub use roman::NumeralAlone;

pub use roman::RomanNumeral;

pub use roman::analyze_chord;

pub use roman::analyze_chord_with_root;

pub use roman::identify_as_tonic_or_dominant;

pub use roman::roman_inversion_name;

pub use scale::BluesForm;

pub use scale::DegreeComparison;

pub use scale::Scale;

pub use scale::ScaleType;

pub use scale::Simplification;

pub use scale::SolfegVariant;

pub use scale::StepScale;

pub use scale::WeightedHexatonicBlues;

pub use serial::HISTORICAL_ROWS;

pub use serial::HistoricalRow;

pub use serial::IndexedTransformation;

pub use serial::LinkClassification;

pub use serial::ToneRow;

pub use serial::Transformation;

pub use serial::TransformationConvention;

pub use serial::TwelveToneMatrix;

pub use serial::historical_row_by_name;

pub use serial::row_to_matrix;

pub use sieve::Sieve;

pub use spanner::Glissando;

pub use spanner::LineEnd;

pub use spanner::LineEnds;

pub use spanner::OctaveShift;

pub use spanner::Pedal;

pub use spanner::PedalForm;

pub use spanner::PedalObject;

pub use spanner::PedalObjectKind;

pub use spanner::PedalType;

pub use spanner::SlideType;

pub use spanner::Spanner;

pub use spanner::SpannerKind;

pub use stream::BarTogether;

pub use stream::StaffGroup;

pub use stream::Stream;

pub use stream::StreamElement;

pub use stream::StreamEvent;

pub use stream::StreamKind;

pub use tempo::DEFAULT_TEMPO_VALUES;

pub use tempo::MetricModulation;

pub use tempo::MetronomeMark;

pub use tempo::ModulationSide;

pub use tempo::TempoText;

pub use tempo::convert_tempo_by_referent;

pub use tempo::interpolate_elements;

pub use tuningsystem::ALL_TUNING_SYSTEMS;

pub use tuningsystem::COMMON_EQUAL_TEMPERAMENTS;

pub use tuningsystem::COMMON_TWELVE_TONE_TUNING_SYSTEMS;

pub use tuningsystem::EqualDivision;

pub use tuningsystem::HISTORICAL_TEMPERAMENTS;

pub use tuningsystem::Monzo;

pub use tuningsystem::Mos;

pub use tuningsystem::MosScale;

pub use tuningsystem::OCTAVE_CENTS;

pub use tuningsystem::Ratio;

pub use tuningsystem::TRITAVE_CENTS;

pub use tuningsystem::Temperament;

pub use tuningsystem::TuningSystem;

pub use tuningsystem::Val;

pub use tuningsystem::moment_of_symmetry_sizes;

pub use tuningsystem::scala::ScalaArchive;

pub use tuningsystem::scala::ScalaDegree;

pub use tuningsystem::scala::ScalaScale;

pub use voiceleading::MotionType;

pub use voiceleading::QuartetOptions;

pub use voiceleading::VoiceLeadingQuartet;

pub use voiceleading::iterate_all_voice_leading_quartets;

pub use voiceleading::verticality_at;

pub use volume::DynamicContext;

pub use volume::Volume;

pub use volume::realize_volume;

Modules

abc

ABC notation export helpers. ABC notation format helpers.

alpha

music21’s experimental modules: notes hashed and streams aligned by them. music21’s alpha package: modules music21 counts as experimental.

analysis

Key-finding and compact analysis helpers.

articulations

Articulations: how a note is played. Articulations: music21’s articulations module.

audiosearch

Finding the notes in a recording: music21’s audioSearch. Finding the notes in a recording: music21’s audioSearch.

bar

Barlines and repeat signs. Barlines: music21’s bar module.

braille

Music in braille: music21’s braille package.

capella

Capella’s CapXML: music21’s capella.fromCapellaXML.

chord

Chord construction, common-name analysis and chord input conversion traits.

chordsymbol

Lead-sheet chord-symbol parsing.

clef

Clefs: which line a note is written on. Clefs: music21’s clef module.

duration

Rhythmic duration primitives.

dynamics

Dynamic marks and the loudness each stands for. Dynamic marks, ported from music21’s dynamics module.

error

Error and result types used by the crate.

expressions

Ornaments and what they play. Ornaments: the part of music21’s expressions module that changes what is played.

features

Features of a piece for machine learning: music21’s features. Features of a piece of music, extracted for machine learning and corpus study: music21’s features package.

figuredbass

Figured bass: the numbers written under a bass note. Figured bass: the numbers written under a bass note, and what they mean.

humdrum

Humdrum **kern scores. Humdrum: music21’s humdrum.spineParser, which reads **kern scores.

instrument

Instruments: music21’s instrument module. Instruments: music21’s instrument module.

interval

Public interval parsing, naming and transposition helpers.

key

Public key and key-signature helpers.

layout

How a score is laid out on the page: music21’s layout objects. How a score is laid out on the page: music21’s layout objects.

lily

LilyPond, written as music21 writes it. LilyPond, written as music21’s lily.translate writes it.

makenotation

Measures, ties, rests, voices, beams and stems worked out for a score that does not say them. Working out what a score leaves unsaid: music21’s stream.makeNotation.

mei

MEI scores. MEI: music21’s mei.base, which reads a score encoded by the Music Encoding Initiative’s schema.

metadata

A score’s title, composer and the rest of what is said about it. A score’s metadata: music21’s metadata.Metadata.

meter

Time signatures: bar length, beat count, beat length and beat division. Time signatures, ported from music21’s meter package.

midi

Minimal MIDI import/export helpers.

musedata

MuseScore’s own .mscx files, and MuseScore run as a converter for the formats it opens. MuseData, the Center for Computer Assisted Research in the Humanities’ encoding: music21’s musedata and musedata.translate.

musescore

MuseScore’s own files, read natively, and MuseScore run as a converter.

musicxmlmusicxml

MusicXML import and export: music21’s musicxml.xmlToM21 and musicxml.m21ToXml. MusicXML export: music21’s musicxml.m21ToXml.

notation

Ties, noteheads, stem direction, colour, lyrics and beams. Notation attached to a note or a chord: ties, noteheads, stem direction, colour and lyrics.

note

Note construction and pitch access helpers.

noteworthy

NoteWorthy Composer’s text format, .nwctxt: music21’s noteworthy.translate.

omr

Correcting scores read by optical music recognition: music21’s omr package. correctors finds the measures whose rhythm was misread and puts the most likely rhythm in their place; evaluators measures how close a score comes to its ground truth before and after.

percussion

Notes with no pitch, and chords of them. Notes with no pitch: music21’s note.Unpitched and percussion.PercussionChord.

pitch

Pitch construction, spelling and pitch-space helpers.

polyrhythm

Polyrhythm timing and pitch-set helpers.

repeat

Words and signs telling a player where to go next. Words and signs telling a player where to go next: music21’s repeat expressions, Segno, Coda, Fine, Da Capo and the rest.

rest

Rests: silence with a written length.

roman

Roman numeral parsing and compact harmonic analysis.

romantext

RomanText, a harmonic analysis written as roman numerals. RomanText: music21’s romanText, a harmonic analysis written measure by measure as roman numerals.

scale

Public scale helpers.

search

Finding music in streams: lyrics as text. Finding music in streams: music21’s search package. A StreamSearcher and the searches beside it find runs of notes by name, rhythm or anything else; the translations turn notes into text, which the approximate searches compare as Python’s difflib does; and a LyricSearcher finds text in a stream’s lyrics, and the notes it is sung to. index_score_parts cuts each part of a score into overlapping stretches of that text, and score_similarity compares every stretch of some scores with every other. A SegmentMatcher finds rows and sets of pitch classes in the notes of a stream, and labels them there.

serial

Tone rows, twelve-tone matrices and serial transformations. Tone rows and twelve-tone serial transformations, a port of music21’s serial module.

sieve

Xenakis sieves, ported from music21’s sieve module.

spanner

Marks joining several notes: slurs. Spanners: marks that join several notes, music21’s spanner module.

stream

Streams: notes, chords and other events placed on a timeline, nested as scores, parts and measures. Music on a timeline: music21’s stream.Stream and the subclasses it nests inside one another.

style

How an object is drawn: music21’s style objects. How an object is drawn: music21’s style objects, as far as the crate keeps them.

tablature

Notes on the strings and frets of a fretted instrument. Notes on the strings and frets of a fretted instrument: music21’s tablature.

tempo

Metronome marks and tempo-word conventions. Metronome marks, a port of the stream-free part of music21’s tempo.

text

Lyrics joined into words and lines, and the articles of titles. Text in scores: music21’s text module. The lyrics of a stream joined into words and lines, the articles of a title moved to its front or its end, and the TextBox a page carries.

tinynotation

TinyNotation, a line of notes written as letters and numbers. TinyNotation: music21’s tinyNotation, a line of notes written as letters and numbers.

tree

A stream’s elements as spans of time, and the moments where what sounds changes. A stream’s elements as spans of time, and the moments where what sounds changes: music21’s tree package, its timespan trees and verticalities.

tuningsystem

Tuning-system ratios, labels and frequency helpers.

variant

Other readings of a passage, kept beside it: music21’s variant module.

voiceleading

Two-voice voice-leading classification and parallel-interval checks. Two-voice voice-leading checks, a port of music21’s VoiceLeadingQuartet.

volpiano

Volpiano, the font chant is written in for the CANTUS database: music21’s volpiano.

volume

How loud a note is: music21’s volume.Volume.

Type Aliases

FloatType

Floating-point type used for pitch space, quarter lengths, and frequencies.

FractionType

Fraction type used by ratio and interval helpers.

IntegerType

Signed integer type used by music21-rs APIs.

Octave

Optional octave number, matching music21’s absent-octave representation.

UnsignedIntegerType

Unsigned integer type used by count-like music21-rs APIs.