See also the Music 254/CS 275b Syllabus.
Music 254 has evolved over more than a decade from a seminar in music representation system to a project-oriented sandbox for applications involving the use of symbolic (discrete) musical data. (Music 252 offers an introduction to easily available notation software; Music 253 delves into the details of the professional notation program SCORE, the internal format of MIDI files, and issues in interchanging data between notation and sound.) It has been an incubator for software applications in such forward-looking areas as polyphonic query, the visualization of tonal harmony, and music query in non-Western (as well as Western) repertories.
Students in Music 254, having acquired skills in notation, MIDI, and data interchange in Music 253, explore the Humdrum Toolkit  to design their own research in areas appropriate to their background and interests. Previous programming experience is not necessary, but a working knowledge of musical notation and elementary concepts of music theory is.
The potential list of topics that may be covered in Music 254 is substantial, but in any given year those most salient to the skills and interests of the class are emphasized. The first month requires regular class meetings, an introduction and preliminary exercises in the use of Humdrum, and individually assigned readings in an area of mutual interest. Lab time is emphasized over the later six weeks of the quarter. Individual help with projects is available.
Arranging meeting times convenient for students from multiple schools and disciplines is a chronic problem. Those with an interest in Music 254 should contact Eleanor Selfridge-Field (esfield // at \\ stanford.edu) at their earliest convenience.
Ultimately, all the application areas covered in Music 254 depend on music analysis. In the analogue world, most analytical techniques are applied to the elaborate explication of single works. Digital tools enable the analysis of whole repertories, but they require two things: (a) encoded music and (b) tools designed to process articulate queries.
Music query, or music search, is a specific instance of music analysis. Query can be specified musically in any number of ways--melodic search, harmonic search, rhythmic search, compositional pattern search, and so forth.
Style evaluation, or style simulation, seeks to define those musical features that constitute a particular style of composition and differentiate it from all others. Feature sets, once defined, can serve as a springboard to the generation of new music in the style of an existing repertory.
The MuseData, KernScores, and Josquin Databases
The CCARH Lab (Braun Music Center #128) provides support for a wide range of notation and analysis applications. The Center for Computer Assisted Research in the Humanities (CCARH), which hosts it, originated the [[MuseData]] encoding format  and has encoded approximately 1,200 complete classical works.
The Humdrum Toolkit, initiated by David Huron and officially hosted at Ohio State University, is complemented by additional tools and an extensive collection of music encoded in the **kern format (KernScores ). Craig Stuart Sapp is also the developer of the KernScores website .
Both of these resources contain extensive amounts of data. The best way to become acquainted with them is to explore them systematically. KernScores will be the more useful for many projects in Music 254/CS 275B, but significant differences in data profiles should be noted. MuseData originates as part-by-part encodings. The data format is intended to support editing, printing, MIDI, and various kinds of re-purposing (re-use). Kern data is through-encoded (all parts are entered at once). MuseData principally contains large-multi-movement works (symphonies, string quartets, ensemble sonatas, operas, oratorios). KernScores principally contains keyboard music. MuseData emphasizes music composed between 1680 and 1850. KernScores has a broader reach, with small quantities of data from the Renaissance, from the early twentieth century, and from folksong repositories.
Beyond these differences in holdings, KernScores offers several paths through its hoildings. The composer and genre lists on the homepage are self-explanatory. At the top of the page, under the search window, the Guided Tour provides useful information on navigation. Data Collection Highlights shows some of the larger constellations of holdings. The Online Humdrum Editor is useful for becoming familiar with the **kern data format used in the database and also for producing short musical examples for print or online use. For full particulars on formats see the CCARH Humdrum Portal.
KernScores has a large number of pre-defined analytical capabilities at the individual work level. Some generate graphical, others alphanumeric displays. The buttons to the left of title listings employ these codes: S=Score, H=Humdrum code, M=MIDI, K=keyscape. A Z, when encountered at the head of a listing, refers to a zip file containing all of the following listings.
On individual work pages, e.g. Chopin's Prelude in C Major, Op. 67, No. 1 (Quasi improvisazione), the user can find translations of Humdrum data ("Data Formats Translation") to notation via several different pieces of software. Of these ABC+ code is among the most robust, MusicXML the most useful for import to Finale and Sibelius. Some of the other formats offer evaluate and/or weigh certain musical features for expressive performance, metrical weighting, and so forth.
The lower portion of individual work pages contains links to produce "keyscape" visualizations of harmonic structure ("keyscapes"), piano-roll views depicting individual voices in relation to each other and showing overall changes of texture, can detect chord roots, and can append them, event by event, to the preceding **kern file.
The Josquin Research Project, directed by Jesse Rodin, contains more than 1,000 pieces of music from the early Renaissance. It was started with the intention of differentiating real Josquin from false attributions to Josquin. The music it contains in in mensural notation. It is designed for musicological queries, which are facilitated through the use of a search panel on the left of the home screen. Music by the composers Dufay, de la Rue, Obrecht, and Ockeghem are included in the data pool.
The Humdrum Toolkit
The Unix-based Humdrum Toolkit originated in the mid-1980s as a small set of commands that can be chained into series to produce concise information about changes inside an encoded musical score. Although the rudiments seem simple, the diversity of questions that can be posed and answered is potentially immense. Because Humdrum is now supported on three continents, CCARH recently constructed a Humdrum portal  to link tools and documentation at diverse locations.
Elements of Musical Style
What constitutes a musical style? As a classroom subject, style is often used as a lens through which to differentiate the work of different composers, genres, historical periods, places, schools of pedagogy, and so forth. It is an umbrella term to which almost any aspect of music can be related. While no one denies that the term is vague in its meaning, two individuals who have defined and articulated specific elements of musical style have also provided taxonomies that are inordinately useful in the development of computer programs for musical analysis.
LaRue's Rubrics of Style Analysis
The noted musicologist Jan LaRue (1918-2003) took a top-down approach to the musical work. His taxonomy of musical features embraces a wide range of musical phenomena, most of which are frequently pertinent to classical music of the past four centuries. In his Guidelines for Style Analysis: A Comprehensive Outline of Basic Principals for the Analysis of Musical Style (New York: W.W. Norton, 1970), LaRue fleshes out his 9-part skeleton into three layers of detail.
Humdrum Lab Pages
Go to the Humdrum Lab portal for a list of exercises to get up to speed with using the Humdrum Toolkit and other programs/environments to work with Humdrum data files.
Previous front page: http://www.ccarh.org/courses/254