Introduction

The principal aim of the partitura package is to handle richly structured musical information as conveyed by modern staff music notation. It provides a much wider range of possibilities to deal with music than the more reductive (but very common) pianoroll-oriented approach inspired by the MIDI standard.

Specifically, the package allows for representing a variety of information in musical scores beyond the onset, duration and MIDI pitch numbers of notes, such as:

  • pitch spellings,
  • symbolic duration categories,
  • and voicing information.

Moreover, it supports musical notions that are not note-related, like:

  • measures,
  • tempo indications,
  • performance directions,
  • repeat structures,
  • and time/key signatures.

In addition to score information, the package can load MIDI recordings of performed scores, and alignments between scores and performances in the Matchfile format used by the publicly available Vienna4x22 piano corpus research dataset.

Supported file types

Musical data can be loaded from and saved to MusicXML and MIDI files. Furthermore, partitura uses MuseScore as a backend to load files in other formats, like MuseScore, MuseData, and GuitarPro. This requires a working installation of MuseScore on your computer.

Conceptual Overview

This section offers some conceptual and design considerations that may be helpful when working with the package.

Representing score information

The package defines a musical ontology to describe musical scores that roughly follows the elements defined by the MusicXML specification. More specifically, the elements of a musical score are represented as a collection of instances of classes like Note, Measure, Slur, and Rest. These instances are attached to an instance of class Part, which corresponds to the role of an instrument in a musical score. A part may contain one or more staffs, depending on the instrument.

In contrast to MusicXML documents, where musical time is largely implicit, time plays a crucial role in the representation of scores in partitura. Musical elements are associated to a Part instance by specifying their start (and possibly end) times. The Part instance thus acts as a timeline consisting of a number of discrete timepoints, each of which holds references to the musical elements starting and ending at that time. The musical elements themselves contain references to their respective starting and ending timepoints. Other than that, cross-references between musical elements are used sparingly, to keep the API simple.

Musical elements in a Part can be filtered by class and iterated over, either from a particular timepoint onward or backward, or within a specified range. For example to find the measure to which a note belongs, you would iterate backwards over elements of class Measure that start at or before the start time of the note and select the first element of that iteration.

Score vs. performance

Although the MIDI format can be used to represent both score-related (key/time signatures, tempo) and performance-related information (expressive timing, dynamics), partitura regards a MIDI file as a representation of either a a score or a performance. Therefore is has separate functions to load and save scores (load_score_midi(), save_score_midi()) and performances (load_performance_midi(), save_performance_midi()). load_score_midi() offers simple quantization for unquantized MIDIs but in general you should not expect a MIDI representation of a performance to be loaded correctly as a Part instance.

Relation to music21

The music21 package has been around since 2008, and is one of the few python packages available for working with symbolic musical data. It is both more mature and more elaborate than partitura. The aims of partitura are different from and more modest than those of music21, which aims to provide a toolkit for computer-aided musicology. Instead, partitura intends to provide a convenient way to work with symbolic musical data in the context of problems such as musical expression modeling, or music generation. Although it is not the main aim of the package to provide music analysis tools, the package does offer functionality for pitch spelling, voice assignment and key estimation.