One of the first and best-known institutes working on different aspects of multimedia is the MIT Media Lab in Boston. Research is going on there on a variety of future applications, such as personal newspaper and holography. In the meantime, many research institutes, universities and computer and telecommunication companies work in the multimedia area.
>From the technical perspective, besides handling the huge amount of data, the timing requirements among all components of the data computation is the major challenge. Traditional data computation tries to finish its task as soon as possible. Real-time systems must work internally within given time bounds, mostly as error-tolerant systems. The fault tolerance in multimedia is generally not the most important aspect.
Another challenge is the integration requirement of different types of media in a multimedia application. In such applications, the traditional media (e.g., text, image) as well as the continuous media (e.g., video, audio), must be processed. Moreover, if a timing requirement is set by a multimedia application, it should hold for both classes (traditional and continuous media) to achieve the timing specification of the application. These media are not independent of each other and therefore the integration requires concepts, which are more complex than just the integration of current concepts. In an integrated system, different components have to process both kinds of data, and moreover, different relations can occur in the form of synchronization among the media.
The notion of multimedia is often defined very differently in the literature in comparison to our (above) description. There is some need for clarification. The technology connections and binding different components, were considered only partially and in isolation from each other. Based on [Steinmetz93], we wrote this book to provide an integrated, consistent and total view.
Basic concepts for the processing of digital audio and video data are based on digital signal processing. Hence, these concepts are described and some possible practical implementations are presented. Different methods for the processing of image , graphics and animation are described. The audio techniques section includes music (MIDI) and speech processing. The understanding of video techniques is built mainly on TV development, including digital representation and HDTV. The originated data rates of these media demand, because of the current quality requirements and available technology, corresponding compression methods. The corresponding hardware and some software are briefly described.
The diminishing cost of optical storage space has contributed significantly to the current development of computer technology. Almost all developments are based on CD-DA (Compact Disc-Digital Audio), known from home electronics.
On the other hand, networks, with their higher bandwidth and their capacity for transmitting all media types, have led to networked multimedia systems . Not such a long time ago, local and distributed multimedia systems consisted of a set of external analog devices controlled by a computer. Today, development tends toward full digital working systems.
The interface between the device domain and the system domain is specified by the computer technology . To utilize the device domain, several system services are needed. Basically, three services exist. These services are mostly implemented in software:
The services of the system domain are offered to the application domain through proper programming abstractions . Moreover, such abstractions can be, for example, part of a multimedia operating system, programming language or object-oriented class hierarchy.
Another topic embedded in the application domain is document handling . A document consists of a set of structured information, represented in different media, and generated or recorded at the time of presentation. Many functions of document handling and other applications are accessible and presented to the user through a user interface .
It turns out that some aspects, such as synchronization aspects, are difficult to locate in one or two components or domains. The reason is that synchronization , being the temporal relationship among various media, relates to many components across all domains.