CSC475 Music Information Retrieval Symbolic Music Representations George Tzanetakis University of Victoria 2014 G. Tzanetakis 1 / 30
Table of Contents I 1 Western Common Music Notation 2 Digital Formats for Symbolic Representations 3 Tools for Symbolic Representations G. Tzanetakis 2 / 30
Introduction Music notation and theory are complex topics that can take many years to master This presentation barely scratches the surface of the subject The main goal is to provide enough background for students with no formal music training to be able to read and understand MIR papers that use terminology from music notation and theory It is never too late to get some formal music training G. Tzanetakis 3 / 30
History of Music Notation Earliest known form of music notation in cuneiform Sumerian tablet around 2000 BC. Initially a mnemonic aid to oral instruction, performance and transmission it evolved into a codified set of conventions that transformed how music was created, distributed and consumed across time and space. Notation can be viewed as a visual representation of instructions for how to perform an instrument. Tablature notation for example is specific to stringed instruments. Primary focus of traditional musicology G. Tzanetakis 4 / 30
Western Common Music Notation Originally used in European Classical Music is currently used in many genres around the world Mainly encodes pitch and timing (to a certain degree designed for keyboard instruments) Considerable freedom in interpretation Five staff lines G. Tzanetakis 5 / 30
Notating rhythm Symbols indicate relative durations in terms of multiples (or fractions) of underlying regular pulse If tempo is specified then exact durations can be computed (for example the first symbol would last 60 seconds / 85 BPM = 0.706 seconds) A different set of symbols is used to indicate rests Numbers under symbols indicate the duration in terms of eighth notes. Each measure is subdivded into 2 half notes, 4 quarter notes, 8 eighth notes. G. Tzanetakis 6 / 30
Time signature and measures Measure (or bar) lines indicate regular groupings of notes Time signature shows the rhythmic content of each measure Compound rhythms consists of smaller rhythmic units G. Tzanetakis 7 / 30
Notating pitches Clef sign anchors the five staff lines to a particular pitch Note symbols are either placed on staff lines or between staff lines. Successive note symbols (one between lines followed by one on a staff line or the other way around) correspond to successive white notes on a keyboard. Invisible staff lines extend above and below G. Tzanetakis 8 / 30
Notating pitches G. Tzanetakis 9 / 30
Repeat signs and structure Repeat signs and other notation conventions can be thought of as a proto programming language providing looping constructs and goto statements Hierarchical structure is common i.e ABAA form Structure = segmentation + similarity G. Tzanetakis 10 / 30
Structure of Naima by J. Coltrane G. Tzanetakis 11 / 30
Intervals Intervals are pairs of pitches Melodic when the pitches are played in succession Harmonic when the pitches are played simultaneously Uniquely characterized by number of semitones (although typically named using a more complex system) (microtuning also possible) G. Tzanetakis 12 / 30
Naming of intervals The most common naming convention for intervals uses two attributes to describe them: quality and number. Quality Quality: perfect, major, minor, augmented, diminished. Number Number: unison, second, third, fifth, sixth, seventh, octave and is based on counting staff positions G. Tzanetakis 13 / 30
Scales and Modes A scale is a sequence of intervals typically consisting of whole tones and semitones and spanning an octave. Diatonic scales are the ones that can be played using only the white keys on a piano. They are called modes and have ancient greek names. G. Tzanetakis 14 / 30
Major/Minor Scales The scales used in composed Western classical music are primarily the major and minor scales. The harmonic minor scale has an augmented second (A) that occurs between the 6th and 7th tone. G. Tzanetakis 15 / 30
Enharmonic Spelling The naming of intervals (and absolute pitches) is not unique meaning that the same exact note can have two different names as in C# and Db. Similarly the same interval can be a minor third or an augmented second. The spelling comes from the role an interval plays as part of a scale as well as the historical tuning practice of having different frequency ratios for enharmonic intervals. G. Tzanetakis 16 / 30
Chords A chord is a set of two or more notes that sound simultaneously. A chord label can also be applied to a music excerpt (typically a measure) by inferring, using various rules of harmony, what theoretical chord would sound good with the underlying music material. The basis of the western classical and pop music chord system is the triad consisting of three notes. Different naming schemes are used for chords. Jazz and Pop music frequently use naming based on triad with additional modifiers for the non-triad notes. G. Tzanetakis 17 / 30
Root, Inversions, Voicings The lowest note of a chord in its default position is called the root. Inversions occur when the lowest note of a chord is different than the root. Voicings are different arrangements of the chord notes that can include repeated notes as well as octaves. G. Tzanetakis 18 / 30
Chord Progressions and Harmony Sequences of chords are called chord progressions. Certain progressions are more common than others and also indicate the key of a piece. Frequently chords are constructed from subsets of notes from a particular scale. The root of the scale is called the tonic and defines the key of the piece. For example a piece in C Major will mostly consist of chords formed by the notes of the C major scale. Modulation refers to a change in key. Chords have specific qualities and functions which are studied in Harmonic analysis. G. Tzanetakis 19 / 30
Jazz Lead Sheets G. Tzanetakis 20 / 30
TuneDex G. Tzanetakis 21 / 30
Pianoroll G. Tzanetakis 22 / 30
Table of Contents I 1 Western Common Music Notation 2 Digital Formats for Symbolic Representations 3 Tools for Symbolic Representations G. Tzanetakis 23 / 30
MIDI Musical Instrument Digital Interface MIDI is both a communication protocol (and associated file format) as well as a hardware connector specification that allows the exchange of information between electronic musical instruments and computers. It was developed in the early 80s and was mostly designed with keyboard instruments in mind. Essentially piano-roll representation of music. G. Tzanetakis 24 / 30
Lilypond Music engraving program Text language for input that is complied Encodes much more than just notes and duration in order to produce a visual musical score Produces beautiful looking scores and is free G. Tzanetakis 25 / 30
Music XML Extensible Markup Language (XML) format for interchanging information about scores Supported by more than a 170 notation, score writing applications Proprietary but open specification Hard to read but comprehensive G. Tzanetakis 26 / 30
Table of Contents I 1 Western Common Music Notation 2 Digital Formats for Symbolic Representations 3 Tools for Symbolic Representations G. Tzanetakis 27 / 30
jsymbolic - jmir Software in Java for extracting high level musical features from symbolic music representations, specifically MIDI files Features capture aspects of instrumentation, texture, rhythm, dynamics, pitch statistics, melody, and chords Part of jmir a more general package for MIR including audio, lyrics, web feature extraction as well as a classification engine G. Tzanetakis 28 / 30
music21 Set of tools written in Python for computer aided musicology Corpora included is a great feature Works with MusicXML, MIDI Example: add german name (i.e., B=B, B=H, A= Ais) under each note of a Bach chorale G. Tzanetakis 29 / 30
music 21 pitch/duration distribution Distribution of pitches and note duration for a Chopin Mazurka using music21. G. Tzanetakis 30 / 30