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.
Multimedia Technology
Multimedia applications need computers that support multi-sensory I/O
devices. At this writing, high-performance computer systems with highresolution 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
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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, and MPEG (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 Technology
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
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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.
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