Detecting Episodes with Harmonic Sequences for Fugue Analysis

International audienceFugues alternate between instances of the subject and of other patterns, such as the counter-subject, and modulatory sections called episodes. The episodes play an important role in the overall design of a fugue: detecting them may help the analysis of the fugue, in complement to a subject and a counter-subject detection. We propose an algorithm to retrieve episodes in the fugues of the first book of Bach's Well-Tempered Clavier, starting from a symbolic score which is already track-separated. The algorithm does not use any information on subject or counter-subject occurrences, but tries to detect partial harmonic sequences, that is similar pitch contour in at least two voices. For this, it uses a substitution function considering "quantized partially overlapping intervals" [Lemström and Laine, 98] and a strict length matching for all notes, except for the first and the last one. On half of the tested fugues, the algorithm has correct or good results, enabling to sketch the design of the fugue

Rhythm extraction from polyphonic symbolic music

International audienceWe focus on the rhythmic component of symbolic music similarity, proposing several ways to extract a monophonic rhythmic signature from a symbolic poly- phonic score. To go beyond the simple extraction of all time intervals between onsets (noteson extraction), we select notes according to their length (short and long extractions) or their intensities (intensity+/− extractions). Once the rhythm is extracted, we use dynamic programming to compare several sequences. We report results of analysis on the size of rhythm patterns that are specific to a unique piece, as well as experiments on similarity queries (ragtime music and Bach chorale variations). These results show that long and intensity+ extractions are often good choices for rhythm extraction. Our conclusions are that, even from polyphonic symbolic music, rhythm alone can be enough to identify a piece or to perform pertinent music similarity queries, especially when using wise rhythm extractions

Efficient pattern matching in degenerate strings with the Burrows–Wheeler transform

International audienceA degenerate or indeterminate string on an alphabet Σ is a sequence of non-empty subsets of Σ. Given a degenerate string t of length n, we present a new method based on the Burrows--Wheeler transform for searching for a degenerate pattern of length m in t running in O(mn) time on a constant size alphabet Σ. Furthermore, it is a hybrid pattern-matching technique that works on both regular and degenerate strings. A degenerate string is said to be conservative if its number of non-solid letters is upper-bounded by a fixed positive constant q; in this case we show that the search complexity time is O(qm2). Experimental results show that our method performs well in practice

As We Are Blind

Œuvres et Recherches 2019:01« As We Are Blind » (2016) est une installation pour « piano mécanique et aura » de Véronique Béland. Au centre d’une pièce à la scénographie épurée, un piano à queue joue la partition la plus intime : celle du spectateur. Conductance, température de la peau, poids de la main, rythme cardiaque... Chaque participant pose la main sur un capteur, et « As We Are Blind » calcule et interprète une production musicale et photographique unique, qui révèle l’« aura » colorée de chaque spectateur

Computational Analysis of Musical Form

International audienceCan a computer understand musical forms? Musical forms describe how a piece of music is structured. They explain how the sections work together through repetition, contrast, and variation: repetition brings unity, and variation brings interest. Learning how to hear, to analyse, to play, or even to write music in various forms is part of music education. In this chapter, we briefly review some theories of musical form, and discuss the challenges of computational analysis of musical form. We discuss two sets of problems, segmentation and form analysis. We present studies in music information retrieval (MIR) related to both problems. Thinking about codification and automatic analysis of musical forms will help the development of better MIR algorithms

Une application web interactive pour l'analyse musicale

International audienceLe patrimoine musical peut se valoriser et s’étudier grâce à des outils numériques, que ce soit à destination des spécialistes (musicologie systématique ou algorithmique), mais aussi pour les apprenants et le grand public. L'analyse musicale, aujourd'hui pratique musicale autonome, a une longue histoire d'interaction avec la pédagogie, notamment en matière de composition, et peut aujourd'hui se pratiquer dans une démarche d'humanités numériques.Nous présentons une application web permettant d'annoter des partitions et de comparer des analyses. Fruit d’une collaboration entre informaticiens de l’équipe Algomus (Lille, Amiens) et musicologues, l’application représente graphiquement des éléments entrant en jeu dans l'analyse de partitions tonales, tels que les motifs, la structure, les fonctions harmoniques et les cadences. Nous proposons en exemple des éléments d'analyse de fugues du premier livre du Clavier bien tempéré de J.-S. Bach ainsi que de quelques quatuors à cordes. L'application web est disponible en licence libre pour faciliter sa diffusion, sa réutilisation et sa réappropriation par d’autres, chercheurs, pédagogues, musiciens ou mélomanes. Nous espérons qu’elle facilitera une pratique démocratisée et collaborative de l'analyse musicale