Logical Structures

There are some terms commonly found in discussions of music notation which most musicians intuitively understand. This section defines the specific usage of these terms in NIFF.

• Score. Each NIFF file contains one score. A score could hold anything from a one bar music example, to a song, a piano sonata movement, or a movement of a symphony in full score. A work in more than one movement would normally be stored with each movement in its own NIFF file.
• Part. A stream of musical events and associated symbols, text and graphics which can be extracted and printed on a part score for an individual performer. A part may contain music to be played sequentially on different related instruments by the same performer (e.g. oboe/English horn). The maximum number of staves used for display is defined for each part.
• Voice. A rhythmically independent stream of musical events within a part, and its associated symbols, text and graphics. Voices can appear and disappear at any time within a part.
• System. The visual framework on a page, where symbols representing simultaneous events in the various parts are more or less vertically aligned. All parts of the score are logically present in every system although some may be "hidden."
• Staff. An arrangement of parallel horizontal lines serving as the locale for displaying musical symbols. It is a sort of vessel within a system into which musical symbols can be "poured." Displayed on it are music symbols, text and graphics belonging to one or more parts.
• Time-Slice. The mechanism by which a specific point in time is identified in the score. Musical symbols representing simultaneous events.are logically grouped within the same time-slice. The music symbols in a NIFF file are physically grouped by page and staff, so symbols belonging to a common logical time-slice may be physically separated in the file. Horizontal placement can optionally be supplied for a time-slice.

There are two types of time-slice: measure start and event. The measure-start time-slice identifies the start time of a measure with respect to the start of the score. The event time-slice identifes the start time of an event such as a note or rest with respect to the start of the measure.

Examples.

The NIFF logical structures were designed to handle situations like the following:

Example 1. In a Mahler symphony score there are three trumpet parts. In one system the trumpets appear on three separate staves (labelled "Tpt. 1", "Tpt. 2", Tpt. 3"), because they are playing a complex canon. In another system they appear all together on one staff, called "Tpts. 1,2,3," because they are playing homophonic music. They are written as chords, with 3 notes on one stem.

In the logical view, the notes played by the trumpets belong to three separate parts.

In the physical view of the canonic system, each trumpet part is assigned its own staff. Each staff is labelled with its own name.

In the physical view of the homophonic system, the three parts are combined together onto a single staff, labelled "Tpts. 1, 2, 3." The simultaneous notes of each chord played by the three trumpet parts appear together with a single stem within each time-slice. Each note indicates the part to which it belongs.

Example 2. Consider a score with divisi writing where the first violin part is temporarily divided into groups. The first violin part is split onto two separate staves in one system, and three separate staves in another system. There are a variety of ways this could be represented in NIFF. The choice depends on the desired result when the parts are to be extracted and printed for individual players:

a) If the first violin part score is to show all the divisi parts, the first violin should be defined as a single part with three voices and a maximum number of staves of three. The notes of this part would be distributed among the one, two or three active voices, each voice presented on its own staff.

b) If separate part scores are to be printed for different first violin players, more than one first violin part should be defined in the NIFF file. All the musical symbols that are to be printed on a particular part score would have that part number indicated. If the same passage is to be printed on two different part scores, both part numbers should be indicated for each symbol within the passage.