Hypermedia and Multimedia
Hypermedia and Multimedia
When someone turns on a computer, puts a CD (compact disc) in its CD drive, and listens to her favorite music while she works on a paper, she is experiencing multimedia. Other examples of multimedia usage include looking at pictures taken from a digital camera. In contrast, surfing the World Wide Web, following links from one site to another, looking for all types of information, is called experiencing hypermedia. The major difference between multimedia and hypermedia is that the user is more actively involved in the hypermedia experience, whereas the multimedia experience is more passive.
Hypermedia is an enhancement of hypertext, the non-sequential access of text documents, using a multimedia environment and providing users the flexibility to select which document they want to view next based on their current interests. The path followed to get from document to document changes from user to user and is very dynamic. This "make your own adventure" type of experience sets hypermedia apart.
Multimedia is defined as the integration of sound, animation, and digitized video with more traditional types of data such as text. It is an application-oriented technology that is used in a variety of ways, for example, to enhance presentations, and is based on the increasing capability of computers to store, transmit, and present many types of information. Some examples of multimedia applications are: business presentations, online newspapers, distance education, and interactive gaming.
Business presentations use presentation graphics software to create and display a series of on-screen slides that serve as a visual aid to enhance presentations. These slides may include photographs, drawings, spreadsheets, or tables. Some presentation graphics programs allow the inclusion of animation and video clips along with still images. Others can automatically convert presentations into World Wide Web pages.
Using a web browser, anyone can browse through pages of online newspapers, read articles, and view pictures or audio/video presentations. In addition, readers can locate a specific article by performing index searches, or by typing detailed requests. In some cases, the user may participate in chat groups and provide feedback to the editors. This type of interactivity requires bringing together images, text, audio, and video elements.
Distance education allows students at remote locations to participate in live instruction through videoconferencing, to collaborate on projects through shared "whiteboards," or to replay instructional material that has been pre-recorded. Using the World Wide Web as the base, a student can browse through a database consisting of course material in various formats: images, audio and video recordings, and textual information. In addition, the student can request more information while reading text, viewing illustrations, or listening to audio presentations.
Interactive games require multimedia delivery systems that can support real-time, three-dimensional imaging as well as interactions among multiple players. Those who have experienced multi-player multimedia games on the World Wide Web know that they can go on for long periods of time and that the number of players is seldom the same. Systems that support interactive gaming applications need to take care of a large number of interacting players for long periods of time.
Multimedia applications need computers that support multi-sensory I/O devices . At this writing, high-performance computer systems with high-resolution monitors and audio output are used as multimedia presentation devices. In these systems, the output devices can present visual material in the form of text, graphics, or video, as well as voice and music components. Multimedia computer systems are providing specialized devices to enter data into the computer system. For example, a scanner can be used to capture still images, voice can be recorded with a microphone and digitizer, and video can be handled with a camera and digitizer. To store multimedia files, which take up a lot of storage, most systems use CD-ROMs (compact disc-read only memory).
In early multimedia systems, interaction between users and the computer was through a mouse and a keyboard. Their limited control of spatial manipulation as required by multimedia applications, especially games, soon made them less than ideal multimedia I/O devices. The new generation of devices includes: multiple-axis joysticks, foot pedals, eye motion tracking systems, and "data gloves"—gloves worn by the user to translate finger and hand position to signals that are then interpreted by the application.
Multimedia systems have to be able to compress data files for transmission and storage, especially those containing motion video and sound. Then, the systems have to decompress such files when the user requests it. Standard video display drivers equipped with software decompression can handle different types of video play-out. However, high-end systems accomplish video decompression with add-on boards that continue to decrease in price. Evolving standards for image and video compression include JPEG (Joint Photographic Experts Group) for still image compression, andMPEG (Motion Picture Coding Experts Group) for motion picture image compression.
Requirements for multimedia systems continue to increase. For example, this includes the ability to format the data for display, which includes fonts, panning, and zooming across different systems.
Hypermedia tools focus on the interactive power of computers, which makes it easy for users to explore a variety of paths through many information sources. As opposed to conventional documents, such as books, that one normally reads one page after the other in the order set by the author, hypermedia documents are very flexible and allow one to explore related documents in any order and navigate through them in any direction.
The hypermedia model is fundamental to the structure of the World Wide Web, which is often based on a relational database organization. In this model, documents are interconnected as in a network, which facilitates extensive cross-referencing of related items. Users can browse effectively through the data by following links connecting associated topics or keywords. Object-oriented and hypermedia models are becoming routine for managing very large multimedia systems such as digital libraries.
Large-scale multimedia applications require significant advances in high-speed networking and storage servers, as well as the production of low-cost presentation devices for the consumer. Trends indicate that processing units will become faster, display devices will become less expensive, memory devices will become larger, and high-bandwidth network access will become present everywhere. These changes will probably result in an abundance of multimedia computer technology for our use and enjoyment.
see also Hypertext; Interactive Systems; World Wide Web.
Ida M. Flynn
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