MML Scope

  1. Scope of the project
  2. Music notation
  3. Approach in the discussion document
  4. Describing music
  5. Student projects
  6. Music structure and delivery

1 Scope of the project

This is a discussion document for a proposed standard of a markup language for music, Music Markup Language (MML). This language will be an SGML (Standard General Markup Language; ISO 8879) subset, following the approach to SGML by XML (Extensible Markup Language -- see W3C). MML should also work seemlessly within the SMIL environment. MML describes the structure of various aspects of music production, such as:

The Music Markup Language should be applicable to many different music-related environments, such as:


2 Music notation

Traditionally the function of music notation is threefold:

With the available modern technologies the function to preserve music is done much better with recording techniques. The notation system on a piece of paper is nevertheless still useful. Such presentation is based on traditional Western music notation which dominates the world. This is not a perfect system, as indicated by the many adaptations over the past few hundred years. Especially during the twentieth century many alternative notation systems have been introduced, eg Schoenberg, Penderecki, Karkoschka, Feldman, Pousseur, Schenker and many more.

For this discussion there are two types of notation:

The idea that music notation could be precise stems from a positivistic view. Preciseness is an unattainable concept -- except the "precise" magnetic or optic recording, which some purists would argue is also not precise. In practice, no matter how precise notation may or can be, the performer nevertheless interprets the notation and expresses it in terms of his or her own experiences. Notation thus merely serves as an indication or guideline of how a piece of music should be performed.

Symbolic systems are far less rigid than physical systems, but they are easier to interpret by the human mind than, for example, wave patterns on an oscilloscope. It is probably impossible to perform from a score of wave pattern printouts.

Given this background, MML will not be an attempt to describe music as wave patterns, nor to fully accommodate Common Western Notation. Many concepts of this notation system are nevertheless useful to describe the structures of music.

Common Western Notation cannot handle nonwestern scales and tunings, nor styles where small differences in pitch or volume are regarded as being important. A language describing all music systems should be able to handle these variations as well. For a practical starting point, however, these variations will be ignored (yet kept in mind) in order to make progress for the description of the most dominant music forms in the world today.


3 Approach in the discussion document

A bottom-up approach is followed here and its implementation is envisaged as follows:

  1. Envisage different scenarios that could be identified within a music environment
  2. Identify possible objects and events (i.e.e abstract elements) within this environment
  3. Create element names. Names should be obvious, not ambiguous and expressed with English words
  4. Identify attributes for the elements
  5. Establish relationships between elements in a hierarchy
  6. Group elements into modules
  7. Apply and test markup to real examples
  8. After some iterations, write the DTD


4 Describing music

Elements and attributes in this discussion document

Each of the identified elements and attributes are described in their own files in a seperate Reference Section. MML is modularized and it is therefore best to read the appropriate module information of a particular element or attribute as well. Input and feedback is required from many different participants in order to streamline contexts and definitions, so please join in discussion and give us some comments or suggestions. Revised documents will be released from time to time.


Problems describing music

Scholars have struggled for centuries devising a system for describing music. Music is a continuous analogue system in terms of the physics of sound waves. Most systems describing this continuum are typically digital. The notes on a staff in traditional Western music notation are digital incisions, translating the analogue continuum onto a graph along vertical and horizontal axes. The Common Western Notation, despite is inaccuracies, is an amazingly economical system, as testified by the magnitude of songs written in this convention. Ideally a system for describing the structure of music should be analogue, but systems doing that, such as Fourier analysis are highly mathematical and difficult to interpret by human performers.

As English is an international language, it will provide the best method of description for the structure of music in terms of keywords. Such a language, however, is also discrete and digital. At best such a system makes snapshots along the continuum of music in two directions: frequency and time. In terms of frequency the smallest discrete unit that will be used in MML will be the cent for relative frequencies, or Herz for absolute frequencies. In terms of time the smallest unit of MML will be the millisecond (ms), or portions thereof, or the relative tick.

Theoretically snapshots can be made at nanosecond level, or anywhere on the time continuum. The purpose, however, of MML is to address music in general, for which such small units are not functional.


5 Student projects

During the initial stage of the MML project, Computer Science students of Prof Vali Lalioti at the University of PRetoria built 2D transformations of MML using the OpenGL graphics library. See the Computer Graphics web site for examples.


6 Music structure and delivery

Music structure (called cantus in SMDL) is distinguished from the delivery methods of a particular structure (related to the gestural and visual domains of SMDL). A piece of music that is marked can be delivered in many different ways:

Audio rendering can be generated in at least two ways:

The role of MML given the above is as follows. MML marks the structural objects or elements of a piece of music. It should be possible to render a marked piece of music by means of any of the delivery systems except perhaps direct human interface. The structure of a piece of music is thus "neutral". The actual delivery of the piece of music will depend on many different aspects, ranging from the music style (eg baroque, rock, jazz, etc) the musical instruments (violin, drums, marimba, etc), phrasing, environmental acoustics, sound processing and so on.

A useful analogy to understand this distinction is the role that CSS (Cascading Style Sheets) plays in HTML (HyperText Markup Language) documents. Just as HTML marks the structure of the document, the structure of a piece of music can be marked. And just as the appearance or delivery of an HTML document can vary according to the selected style sheet, a piece of music can be delivered in many different ways.

This analogy breaks down to the extent that in an orchestrated piece of music each instrument "plays its own part". This means that there may be many different melodic lines in a song -- many different "songs" contained in a song. Or to put it differently, there are many different possible styles that are to be presented simultaneously in a piece of music, so there are in effect many different layers of "text". In terms of the analogy, there are numerous style sheets that are implemented simultaneously.

Music as a layered form of communication is thus more complex to present in a visual format than human languages.

The MML project should incorporate the ability to deliver the structure of music pieces in many different systems. From a notational point of view, such systems should include traditional Western notation and any of the numerous different systems introduced since the 1950s such as ASCII coding systems.

The minimum required structural systems for describing music are the following, each consisting of several subsystems:

Although a piece of music does not need to be marked with all the modules, the time and frequency elements are essential to mark the basic structure of music. It would be impossible to mark music without these two modules.

Also see Notes on MIDI and Notes on Synthesizers


1999, 2000 Author: Jacques Steyn
Last edited: 17 September 1999, 2000