Rhythm Toolbox

This repository contains tools for studying rhythms in symbolic format. It was developed for the study of polyphonic drum patterns, but can be adapted for other types of patterns. It implements various descriptors derived from scientific literature; see Descriptors for a full list with references.

Installation

pip install git+https://github.com/danielgomezmarin/rhythmtoolbox

Usage

Rhythm Toolbox supports multiple representations of symbolic rhythm. Across all representations, Rhythm Toolbox operates at a 16th note resolution, or 4 ticks per beat in MIDI terms. If data is passed in at a different resolution, it is resampled by associating each onset with its closest 16th note position.

MIDI

To compute descriptors from a MIDI file:

from rhythmtoolbox import midifile2descriptors

midifile2descriptors('midi/boska/3.mid')

Piano roll

A piano roll is a (N, V) matrix, where N is a number of time steps and V is a number of MIDI pitches. Any positive value represents an onset; Rhythm Toolbox does not currently consider velocity.

To compute descriptors from a piano roll:

from rhythmtoolbox import pianoroll2descriptors

pianoroll2descriptors(roll)

Pattern list

A pattern list is a list of lists representing time steps, each containing the MIDI note numbers that occur at that step.

To compute descriptors from a pattern list:

from rhythmtoolbox import pattlist2descriptors

pattlist = [
    [36, 38, 42],
    [],
    [],
    [38, 42],
    [46],
    [46],
    [36, 38, 42],
    [],
    [42],
    [38],
    [36, 42],
    [],
    [38, 46],
    [46],
    [42, 64],
    [],
]
pattlist2descriptors(pattlist)

Descriptors

The following descriptors are discussed in Gómez-Marín et al, 2020. Additional sources are listed where applicable. The mapping of MIDI instruments to frequency bands can be found in midi_mapping.py.

Name	Description
noi	Number of instruments
polyDensity	Number of onsets
lowDensity	Number of onsets in the low freq band
midDensity	Number of onsets in the mid freq band
hiDensity	Number of onsets in the high freq band
lowness	Fraction of onsets in the low freq band
midness	Fraction of onsets in the mid freq band
hiness	Fraction of onsets in the high freq band
stepDensity	Fraction of steps with onsets

The following descriptors are valid only for 16-step patterns:

Name	Description	Reference
sync	Syncopation
lowSync	Syncopation of the low freq band
midSync	Syncopation of the mid freq band
hiSync	Syncopation of the high freq band
syness	Syncopation / density
lowSyness	Syncopation / density of the low freq band
midSyness	Syncopation / density of the mid freq band
hiSyness	Syncopation / density of the high freq band
balance	Monophonic balance	Milne and Herff, 2020
polyBalance	Polyphonic balance
evenness	Monophonic evenness	Milne and Dean, 2016
polyEvenness	Polyphonic evenness
polySync	Polyphonic syncopation	Witek et al, 2014

Attribution

If this repository is useful for your research please cite the following paper via the BibTeX below.

@article{gomez2020drum,
  title={Drum rhythm spaces: From polyphonic similarity to generative maps},
  author={G{\'o}mez-Mar{\'\i}n, Daniel and Jord{\`a}, Sergi and Herrera, Perfecto},
  journal={Journal of New Music Research},
  volume={49},
  number={5},
  pages={438--456},
  year={2020},
  publisher={Taylor \& Francis}
}

To cite the initial version of this repository (Nov 2018), checkout commit 6acdb69a60153d08.

The MIDI drum patterns examples included in midi/boska and midi/sano were provided by Jon-Eirik Boska and Sebastián Hoyos, respectively.