Transforming Electronically Encoded Music

Submitted by

Baron Schwartz

Computer Science



Section 1 (9:15 AM)

June 24, 2002

$Revision: 1.2 $ $Date: 2002/06/24 04:47:38 $


TCC Advisor: Peter Norton

Technical Advisor: Worthy Martin

On my honor as a University student, on this assignment I have neither given nor received unauthorized aid as defined by the Honor Guidelines for Papers in TCC Courses.

Signed: _________________________________

1. Problem Statement

Is it possible to transform musical works encoded using Music Description Language (MDL) into other electronic formats, such as Postscript, PDF, Mup, SVG, and MIDI?

2. Importance

The state of the art in representing music electronically is highly disorganized. Many ways exist to represent music, but they are mostly intended for specific purposes. Many formats are proprietary, forcing developers to buy licenses to closely guarded secrets. Constant re-invention of representation languages results in the proliferation of incomplete and incompatible formats.

The importance of an open, extensible standard representation of music in electronic format could be tremendous. Musicians, composers, publishers, and performers all over the world could use musical documents for very different purposes, without having to convert between file formats or adjust the representation for a particular purpose. A file could be created by a graphical editing interface, then used unaltered by a publisher or played by a MIDI player.

University Library Staff member Perry Roland <> has created MDL, an Extensible Markup Language (XML) Document Type Definition (DTD) to represent Western musical notation in an open, extensible format. He has not yet successfully used a document based on MDL to produce printed output or MIDI. Determining the feasibility of MDL for these purposes is an important step in evaluating its usefulness.

3. Relation to Published Research

Michael Kay lists four XML musical notation formats in XSLT Programmer's Reference, 2nd Edition (Kay, p.14). He mentions that XLST can transform these files into chords, MIDI, and notation. Only a handful of articles exist on XML DTDs for musical notation; notables include several chapters ofWalter Hewlett and Eleanor Selfridge-Field's The Virtual Score, written by Perry Roland (creator of MDL), Michael Good (creator of MusicXML), and others. Eleanor Selfridge-Field's Beyond MIDI details the purpose of MIDI and discusses ways to represent music electronically from many perspectives. More research is published on the Web; I am presently assessing its quality and relevance.

My research is more specifically targeted at assessing the feasibility of one format for several purposes; this deviates from other research in that most formats are optimized for only one purpose. However, my research is an extension of the scope of what others have done.

4. Scale and Complexity

Extensible Stylesheet Language: Transformations (XSLT) is the de facto standard for converting XML documents into other formats. I propose to use XSLT to tranform an MDL-encoded musical work into various formats. While non-trivial, this should be possible within the course of two semesters of thesis research classes and one semester of supervised study.

5. Competence

I am proficient in XML and several related technologies. I currently use XML and XSLT at work to maintain documentation and transform it into high-quality printable formats. I have also studied Lisp, a functional programming language upon which XSLT is partially based.

6. Resources

This project will require a significant investment of time by the researcher. Bi-weekly meetings, on average, will be required with the technical advisor and Mr. Roland. The only other resources required are a computer and various software. Computers are readily available, and the necessary software is distributed free of charge over the Internet.

7. Glossary

Standard file format for press-quality printing.
Adobe's Portable Document Format, a universal file interchange format.
A program and file format for producing Postscript musical notation from a text file.
Scalable Vector Graphics, an XML image format. Sometimes compared to Postscript.
Musical Instrument Digital Interface, a standard means of music for computer playback.
Music Description Language, an XML DTD created by Perry Roland.
Extensible Markup Language. The state of the art in representing information in a text file as a set of data with relationships between items.
Document Type Definition. Specifies the form to which a particular XML document must adhere.
Extensible Stylesheet Language: Transformations. A programming language for transforming XML documents to other formats.

8. Works Cited

Hewlett, Walter B. and Eleanor Selfridge-Field, eds. The Virtual Score: representation, retrieval, restoration. Computing in Musicology, 1057-9478: v.12. Cambridge: MIT Press, 2001.

Kay, Michael. XSLT Programmer's Reference, 2nd Edition. Birmingham, UK: Wrox Press, 2001.

Selfridge-Field, Eleanor, ed. Beyond MIDI: The handbook of musical codes. Cambridge: MIT Press, 1997.