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Star Wars Thematic Corpus Github Guide

This document serves as an extended table-of-contents for the Star Wars Thematic Corpus, outlining its organization and the kinds of files contained in the final corpus.

Star Wars Thematic Corpus (SWTC) - version 1.0

This repository contains a dataset of melodic and harmonic transcriptions of the major themes from the complete Star Wars trilogies (Episodes I-IX). There are a total of 64 distinct themes, each with its own file available in multiple formats (.sib, .musicxml, .krn), with the primary human-computer-readable encoding in humdrum format (https://www.humdrum.org/).

Contributions

This corpus was originally transcribed by Frank Lehman in Sibelius format, and released as a complete catalog in the form of a large table document including a score engraving of each theme, the films in which the theme recurs, and the timestamp for its original presentation in the associated film. This document was released publicly in 2022 and is available on Lehman’s website (https://franklehman.com/starwars/) Expansion of the themes to their unrestricted size (measures were previously constrained by space in the pdf document) and updates to the Sibelius file transcriptions were undertaken by Frank Lehman, and subsequent conversion to humdrum format was undertaken by Claire Arthur and John McNarmara.

Directory Organization

The corpus’s musical files have been organized into folders based on the three trilogies of “main-line” Star Wars movies: themes originating in Episodes IV, V, and and VI appear in the “Original Trilogy Theme ,” folder, those originating in Episodes I, II, and III are in the “Prequel Trilogy…” folder, and those originating in Episodes VII, VIII, and IX are in the “Sequel Trilogy…” folder. Within each of these folders, the corpus data is further categorized based on file extension as follows:

Sibelius Files - This is the format in which the themes were initially digitized and which were used for the initial harmonic and formal transcriptions. Chords are labeled using “Chord Symbol” objects within Sibelius, and text contains Roman numeral annotations, pedal notes, cadential annotations, with any additional annotations encoded as “lyrics”.

XML - These uncompressed musicxml files are the direct output of Sibelius’s batch export feature. They are included to facilitate viewing the corpus content in other music notation programs such as Finale or Musescore.

Krns - We converted the musicxml files to kern (.krn) format using the musicxml2hum command within the humlib library (Sapp, 2021; available at https://github.com/humdrum-tools/humlib). We then processed these files with several scripts (see below) to reformat and reorganize the raw output data. Finally, we manually reviewed and edited each file to ensure that formatting and notation were consistent across the corpus.

Kern Files

We include the following spine types in the SWTC humdrum files: **kern, **harte, **harm, **altharm, **pedal, **cadence, and **text. Both **kern and **harm are preexisting humdrum format standards (see https://www.humdrum.org/guide/ch02/ and https://www.humdrum.org/rep/harm/, respectively), whereas the rest have been customized for this specific corpus. For the SWTC, we propose a new standard humdrum representation for chord symbols, **harte, based on an existing proposed standard for representing chord symbols (Harte, 2010) widely in use already within the music information retrieval community. Descriptions of each kern spine can be found in Table 1 below. Since not every file contains information for the relevant spine, the number of spines per file is variable. At a minimum, each file must contain a **kern (melodic information) spine, and may optionally include all other spines as relevant. For instance, themes with no clear tonal center do not contain **harmor **altharm spines (functional harmony representations). Themes with explicit harmonic accompaniment will include a **harte spine (and **harm spine if appropriate), however, files with only a **harm spine but no **harte spine are indicative of implied harmony only.

Table 1. Kern spines (columns), and the description of each, for the SWTC.

Each file includes relevant bibliographic metadata in the humdrum reference records (see: https://www.humdrum.org/reference-records/). Reference records at the top of each file include: the composer, title, associated work, date of composition, transcriber, and digital encoders.

Harte Encoding

The inclusion of a new non-functional harmony encoding in humdrum format is aimed to facilitate data sharing, and provide a more robust encoding method for songs that contain harmony where traditional Roman numeral interpretations frequently become inappropriate or inconsistent (e.g., popular, jazz, and film music). We chose the representation proposed by Harte (2005, 2010) since it provides a comprehensive method for encoding any chord as well as a simple, condensed method for common chords; and because it is already widely encountered in the music information retrieval (MIR) community. See Harte (2010) for a complete explanation.

Note that we had to make one small modification in order to make the data more appropriate for use with the the humdrum toolkit and other humdrum tools (e.g., Verovio Humdrum Viewer, Sapp; humdrumR, Condit-Schultz). That is, since in kern the lower case letter “b” is used to represent chordal inversions, a flat is instead represented with a minus symbol (-). Since Harte encodings are specified in the following format: root: intervals above bass, we chose to convert flats in the root encoding to be consistent with humdrum syntax. In addition, we observed a lack of explicitness in Harte’s documentation as to the default syntax for representing intervals above the bass. This is extremely important as the exact intervals must be easily understood and systematically applied so as to allow for ease of use with computational methods. We inferred from Harte’s examples that perfect intervals and major imperfect intervals are defaults, and therefore any minor, augmented, or diminished intervals must be explicitly specified (see, e.g., the interval lists for the major and minor ninth chords, repsectively). This problem extends to the bass interval. In practice, it appears that users of Harte's system at times list the bass interval instead as the 'member of the chord' that is in the bass. While it most commonly is the case that the bass note is a member of the chord, there are cases where this is not true (e.g., C minor over a D.) Again, while Harte (2010) technically does not clearly disambuguate, he does refer to the object as an interval. Moreover, an example provided (Harte 2010, p.99) illustrates a C# minor-seventh chord with the third in the bass as: C#: (a,b3,5,b7)/b3 which would imply that the shorthand version would be: C#:min7/b3 and not C#:min7/3. As such, a C major 7th chord over the 7th would be written as C:maj7/7 (default interval is major), while a minor 7th chord or major-minor 7th must be written as explicitly over a minor seventh (e.g., C:min7/b7; C:7/b7, respectively). Finally, in our corpus chords are labeled at their beginning time point (i.e., onset) and null tokens are used to extend the duration of the chord until it is superceded by a newly struck chord. Where a silence is explicitly intended to be encoded, we use "N" following Harte syntax.

The table of shorthands for the most commonly used symbols (copied from Harte, 2010, p.103) are outlined below:

In addition to these, modifiers may be added to shorthands using \* for omissions and () for added intervals, in the following format:
root : shorthand (extra-intervals) / bass

Helpful Examples

A made-up example shown in the humdrum syntax may be found below:

Scripts

The files in the “Scripts” folder were used to revise and edit the krn files created from the musicxml conversion into humdrum format. Add_header.py - adds global interpretations to krn files describing the composer, composition date, theme title, and associated movie of each theme. It also adds information about the corpus encoder and editors. Remove_empty.sh - removes spines that do not contain any data Remove_space.py - replaces spaces in file names with underscores Renamespines.sh - takes the raw output from “musicxml2hum” and renames and reorders the spines appropriately. Rn2harm.py/sh - converts harmonic information from rntxt formant to humdrum format. Unbeam.sh - removes beaming information from **kern spines. Unbracket.sh - removes brackets from **kern spines.

License

Shield:

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.