Multimedia - notes and pointers

Note that this 'definition' excludes digital representations that do not preserve or create any sensory features of the objects they represent. (A database for instance, of personnel records that solely consist of numerical or textual fields, will not be considered 'multimedia'.)

In fact, more often than not the objects underlying digital representations are man-made and themselves analog representations (e.g. images, text, sound, etc.) of real-world objects. (Strictly speaking, 'text', as a concatenation of characters drawn from a finite set of symbols, is itself a digital object type; hand written text, however, clearly includes a strong analog component.)

Whereas storing and communicating analog representations of (real-world) objects require a range of different physical media (e.g. paper, film, air (!), magnetic tape, electromagnetic fields, etc.), digital representations can in principle be stored on and communicated via a single physical medium respectively. (Hence 'multimedia' may be considered a misnomer; it is actually the replacement of several (multi) physical media by (potentially) a single one that the term 'multimedia' alludes to.)

creation	description	storage	management
manipulation	annotation	analysis	search
access	retrieval	communication	presentation

- in general both hardware and software - are needed to perform these operations. In fact, what we have listed are classes of operations; hence tools can be grouped in corresponding classes. None of them can be seen in isolation. Application of these operations/tools is usually subject to some sequential or hierarchical order, they are of different degrees of complexity, and there is substantial overlap between the issues pertaining to the operations listed.

Multimedia tools are either generic or application specific: different application areas and different applications within these areas may impose different requirements on the specificities of the various types of operations listed above.

The particular features of authoring tools for instance, clearly depend on the type of content to be created: requirements for authoring a set of courseware modules are likely to be quite different from those for compiling an interactive multimedia newspaper or for producing a video clip.

Yet, the basic features of these operations do provide a common ground for most if not all contexts of multimedia content. They are largely independent of any given application domain. The same holds for the basic features of multimedia systems architectures.

heterogeneity, distributivity, federation, scalability, interoperability, sustainability and commercial viability of multimedia repositories / systems; multimedia production systems; embedded multimedia (e.g. background multimedia libraries), human-centred design techniques, etc.

Adherence to standards in the design and implementation of multimedia systems is a necessary condition for (inter alia) interoperability, sustainability and commercial viability. Standards issues arise in connection with several of the above classes of operations, in particular creation (representation formats and languages), description (metadata, identifiers, languages) and communication (protocols).