Access

All files in the Star Wars Thematic Corpus (SWTC) are downloadable via Github repository (https://github.com/Computational-Cognitive-Musicology-Lab/Star-Wars-Thematic-Corpus) as a publicly accessible symbolic (human- and machine-readable) corpus of film music, and is open source under a Creative Commons license (CC-BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/). We also include a spreadsheet in the repository that contains additional metadata not referenced in the humdrum or musicxml files, such as the number of appearances of the theme throughout the original full score. As we plan to update this corpus in the future, we release the current corpus (detailed here), released in 2022 as version 1.0.

Description

The nine Star Wars scores each contain between two and three hours of originally composed music. The percentage of score material from recurring themes is between roughly 20% (Episode II) and 40% (Episode VIII) (Lehman, 2018a). Out of this large oeuvre, there can be discerned 64 distinctive, recurring, and symbolically meaningful themes and motifs, commonly referred to as leitmotifs. While there exist no authoritative guidelines for what should and should not be designated a leitmotif, the classification and naming of these materials is based on rigorous criteria developed in Bribitzer-Stull (2015) and systematized in Lehman (2018a, 2022). The two key criteria for inclusion are: 1) musical distinctiveness and 2) recurrence across at least three discrete spans of film music (cues). The relative openness of this definition, particularly the distinctiveness condition, permits certain themes that might otherwise go unnoticed to be admitted into the corpus (e.g., "Revelations," "Happy Landing," "Map"). Excluded at this time are alternative forms of musical materials (variations), musically indistinct motives (incidental themes), memorable but non-repeating materials (set-piece themes), source music, and music composed by anyone other than John Williams.

Leitmotifs in Star Wars are also highly variable in their appearances, and may lack the sorts of clear or definitive statements typically sought in corpus studies. For the purposes of the SWTC, a judgment call was made as to the most representative and/or characteristic guise of a given theme, sometimes involving a degree of idealization from any one specific usage (e.g., "Leia's Theme"). While some themes are internally complex, multi-sectional, or structurally variable, only the most basic and distinguishing measures of a leitmotif were included. Future expansions of this corpus may reintegrate these materials, much of which has already been transcribed and encoded.

Per typical procedures for encoding musical corpora, a reductive approach has been taken for all 64 themes, with a single, monophonic, melodic line represented, harmonic information conveyed through chord symbols, and harmonic function with Roman numerals in cases where a tonal center is clear. We also include symbolic indicators for keys, cadences, and four kinds of formal boundaries (full, sectional, abrupt, and half-cadential conclusions). All transcription work was performed by author F.L..

At times, the limits of what chord symbols and Roman Numerals can convey are pressed. Williams's harmonic language is quite sophisticated (Lehman, 2018b), informed by his background in jazz (as discernible in themes "Luke and Leia" and "Gloomy Courtship") and the growing popularity of minimalist techniques like ostinati, drones, and static harmony (as operative in "Duel of the Fates," "Snoke," etc.). Standard chord symbols do a poor job conveying the active and harmonically-generative basslines that undergird many leitmotifs like the "Main Theme" or "TIE-Fighter Attack." In such cases, the SWTC employs a combination of liberally included extensions and suspensions, slash and polychord notation, and a dedicated pedal point data layer for dissonant bass notes. Importantly, these pedal indicators do not correspond to fixed bass pitches per se, but rather moments when a given triadic chord is not supported by a consonant chord-tone in the bass.

Digital Encoding and Representation

All 64 files in the SWTC are available in multiple formats: their original Sibelius format, uncompressed musicXML, and humdrum (Huron, 1995; Sapp, 2021). In the humdrum files, the musical information is preserved in time-aligned columns, called spines, where each spine contains a different type of musical information. (For full humdrum documentation, see https://www.humdrum.org/guide/). 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/), 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. 2 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 spine (melodic information) , and may optionally include all other spines as relevant. For instance, themes with no clear tonal center do not contain **harm or **altharm spines (functional harmony representations). Themes with explicit harmonic accompaniment will include a **harte spine (and **harm spine if appropriate), however, files with a **harm spine but no **harte spine are indicative of implied harmony only. The **altharm spine allows for alternative plausible functional-harmonic interpretations for any single chord event—a fairly common occurrence in Williams's enriched tonal vocabulary. (For example: the penultimate chord in "Yoda's Theme" is analyzed a first as V[b9], but contextual features justify an alternative, more-plagally oriented interpretation of iv[add6] over a G-pedal.)

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. The conversion of the corpus into humdrum format, including encoding details and decisions, was shared by authors CA and JW. An example excerpt from one file is shown in Figure 1.

Figure 1. Sample encoding of a selected file from the SWTC (showing measures 1-3 only), "Imperial March" theme (file #10 from the 'Original Trilogy' corpus).

Harte Encoding

Trevor DeClercq (2015) discusses a well-known issue in the field of computational musicology relating to the lack of any standardized encoding format for harmony. He comments that "each format has its advantages and disadvantages", and that while "it is not impossible to convert and translate between different encoding formats…it makes this type of research much more difficult." The introduction here of a new non-functional harmony encoding in humdrum format is aimed to facilitate data sharing, and provide a more robust encoding method for music containing harmony where traditional Roman numeral interpretations frequently become inappropriate or inconsistent. We chose the Harte representation (Harte et al., 2005; Harte, 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 Note 2). As illustrated in Harte's basic encoding scheme shown in Table 2 (from Harte et al., 2005, p.69), the most common chord types (triads and seventh chords) can be represented with a "Root: shorthand" notation (column 2), which contain the root plus the intervals above the root as shown in column 3.

For example, a C major chord would be written as "C:maj", a G major-minor seventh chord as "G:7", or an F chord with a suspended fourth as "F:sus4". Omissions can be indicated in the interval list with an asterisk (e.g., no third = *3), and additions in parentheses. Non-common chords can always be represented by indicating any root note (even if arbitrary) and the collection of intervals above it (e.g., "C:(3,#5,6,7)"). See Harte (2010) for a complete explanation.

Summary Statistics

The corpus comprises 64 files, one for each theme. The average number of measures per theme is 8.8, with a standard deviation of 5.5 measures. The longest theme in the corpus is 35 measures and the shortest is technically one measure ("Duel of the Fate Ostinato" is encoded as one measure between repeat signs). Of the 64 files, 50 have been given an exclusive key interpretation. This means that approximately 20% of the corpus, or 9 themes, can be considered not to have any prevailing key. This subset of material therefore contains no functional harmony interpretations. Interestingly, only 14 files (themes) are nominally in major mode, with the other 36 files nominally minor. Some general corpus census statistics are presented in Table 3.

A distribution of the pitch content is illustrated in Figure 2. While the bulk of thematic content can be seen as distributed over the two-octave range above C4 (middle C), this figure illustrates the impressive pitch range of John Williams's thematic material. Figure 3 illustrates the most prevalent chord types in descending order. Finally, Figure 4 shows each file in the corpus–grouped by trilogy in chronological order–illustrating the duration of each file both in terms of overall duration in seconds as well as via note counts. Songs with a larger difference between note counts and duration therefore exhibit greater note density.

Figure 2. Pitch distribution in the STWC. Octave register is indicated below each new octave (e.g., C4-B4, C5-B5, etc.) and each shaded a different color.

Figure 3. Distribution of chord types (top 80% only) in the SWTC. This ignores distinctions based on bass notes (inversions). Note the high prevalence of chord types such as sus chords and minor-major 7th chords which are practically non-existent in music of the Common Practice Era (e.g., see Devaney et al., 2015).

Figure 4.. Duration of each theme (file) as measured in terms of the number of total notes (x) and the total duration in seconds (). The three collections of themes belonging to each trilogy are placed in chronological order.