Authoring Dimensions

This highly complex process of authoring multimedia content can be viewed as a three dimensional activity, as shown in Figure 1.

These three dimensions, namely, temporal, spatial and digital dimensions are not entirely orthogonal. Therefore, changes in one dimension can effect the composition in the other dimensions.

The temporal dimension relates to the composition of the multimedia presentation in time. The main aspect of the temporal composition is the narrative, which is akin to the plot of a story. In traditional media – such as a novel or a movie – the narrative is fixed, and the user is expected to traverse the narrative as per the predetermined plot. In interactive multimedia systems, the user is given the ability to vary the order in which the content is presented; in other words, the user can change the narrative. The Movement Oriented Design (MOD) paradigm (Sharda, 2004b) provides a model for the creation of temporal composition of multimedia systems.

The spatial dimension deals with the placement and linking of the various multimedia elements on each ‘screen’. This is similar to the concept of mis e scéne used by the film theorists (Cook and Ernink, 1999). In a time varying presentation – such as a movie or an animation – the spatial composition changes continuously: most of the time the change is smooth, and at other times the change is abrupt, i.e. a change of scene. The spatial composition at any point in time must relate to the narrative, or the plot of the temporal composition, while fulfilling the aims and objects of the system. The Multimedia Design and Planning Pyramid (MUDPY) model (Sharda, 2004c) provides a framework for developing the content starting with a concept.

The digital dimension relates to coding of multimedia content, its meta-data, and related issues. Temporal and spatial composition was part of pre-digital multimedia designs as well, e.g. for films, slide shows, and even the very early multimedia projection systems called the Magic Lantern. The digital computer era, particularly over the last two decades has provided much greater freedom in coding, manipulating, and composing digitized multimedia content (Manovich, 2001a). This freedom brings with it the responsibility of providing meaningful content that does not perform fancy ‘bells and whistles’ (e.g. bouncing letter, or dancing eyeballs) just for the sake of it. The author must make sure that any digital artifact relates to the aims and objectives of the presentation.