Unit 7: Multimedia

Doug Engelbart Explores Hyperspace

In 1950, Doug Engelbart envisioned how computer technology could magnify human mental abilities and provide people with new powers to cope with the urgency and complexity of life. Engelbart's augmented system introduced the mouse, video display editing (the forerunner to word processing), mixed text and graphics, windowing, outlining, shared-screen video conferencing, computer conferencing, groupware, and hypermedia. Today many of Engelbart's inventions and ideas have become commonplace.

Engelbart now heads the Bootstrap Institute, a nonprofit think tank dedicated to helping organizations make decisions with the future in mind.

FOCUS ON COMPUTER GRAPHICS

Computer graphics can take a variety of forms; we'll consider several important types in this unit.

Painting: Bit-mapped Graphics:

An image on a computer screen is made of pixels&endash;tiny dots of white, black, or color arranged in rows.
Painting software allows you to "paint" pixels on the screen with a pointing device. Painting programs create bit-mapped graphics&endash;pictures that are, to the computer, simple maps showing how the pixels on the screen should be represented.

Images created with monochrome graphics are painted in a single color on a solid background. Shades of gray are simulated by dithering&endash;intermixing of black and white pixels to create the illusion of a true gray tone. Gray-scale graphics allow each pixel to appear as black, white, or one of several shades of gray.
Today computers typically have 8-bit color, allowing 256 possible colors to be displayed on the screen at a time. But true color&endash;photo-quality color&endash;requires hardware that can display millions of colors at a time. True color typically uses 24 or 32 bits of memory for each pixel on the screen.

The number of bits devoted to each pixel&endash;called color depth or pixel depth&endash;is one of two technological factors limiting an artist's ability to create realistic images with a bit-mapped graphics program. The other factor is resolution&endash;the density of the pixels, usually described in dots per inch, or dpi.
Diagonal lines, curves, and text characters have the "jaggies"&endash;jagged, stair-step-like bumps that advertise the image's origins as a collection of pixels. Some painting programs get around the "jaggies" problem by storing the image at a higher resolution than the screen can display.

Digital Image Processing: Photographic Editing by Computer:

Digital image processing software allows the user to manipulate photographs and other high-resolution images with tools similar to those found in paint programs.

Drawing: Object-oriented Graphics:

Object-oriented graphics programs store graphics as collections of shapes (represented internally as formulas) rather than as collections of dots.
Many professional drawing programs store images using PostScript&endash;a standard page-description language for describing text fonts, illustrations, and other elements of the printed page. PostScript is built into many laser printers and other high-end output devices, so those devices can understand and follow PostScript instructions.

Object-oriented graphics and bit-mapped graphics each offer advantages for certain applications. Bit-mapped image editing programs give artists and photo editors unsurpassed control over textures, shading, and fine detail; they're widely used for creating screen displays and for embellishing photographic images. Object-oriented drawing and illustration programs are a better choice for creating graphs, charts, and illustrations with clean lines and smooth shapes. A growing number of software applications include features of both.

3-D Modeling Software:

With 3-D modeling software graphic designers can create three-dimensional objects with tools similar to those found in conventional drawing software.

CAD/CAM: Turning Ideas into Products:

Computer-aided design (CAD) is the use of computers to design products. CAD tends to be cheaper, faster, and more accurate than traditional design-by-hand techniques.

Computer-aided design is often linked to computer-aided manufacturing (CAM).
The emergence of CAD/CAM has streamlined the design and manufacturing process. The combination of CAD and CAM is often called computer-integrated manufacturing (CIM); it's a major step toward the fully automated factory.

Presentation Graphics: Bringing Lectures to Life:

Presentation graphics software is designed to automate the creation of visual aids for lectures, workshops, training sessions, sales demonstrations, and other presentations.
Specialized presentation graphics programs are most commonly used for creating and displaying bullet charts that list the main points of a presentation. Such bullet charts can be output as color slides, overhead transparencies, handouts, or used as on-screen computer "slide shows."

Rules of Thumb: Creating Smart Art:

Some guidelines to make the most of the computer as a graphic tool:

Overcome art anxiety.

Choose the right tool for the job.

Borrow from the best.

Don't borrow without permission.

Protect your own work.

DYNAMIC MEDIA: BEYOND THE PRINTED PAGE

Computers today allow you to work with time-based media as well as static documents; time is an important dimension in these programs.

Animation: Graphics in Time:

Creating moving pictures from still pictures&endash;this illusion is at the heart of all animation.
Before computers, animated films were hand-drawn, one still picture, or frame, at a time. Animation software automates much of the repetitive work in animation so animators can focus on the creative parts of their work.

Desktop Video: Computers and TV:

Conventional television and video images are stored and broadcast as analog (smooth) electronic signals. Within the next decade that's likely to change, however, as the television and video industries switch to digital video storage and transmission.
Because digital video can be reduced to a series of numbers, it can be edited, stored, and played back without any loss of quality. Digital video, like text, numbers, and computer graphics, can be treated as data by computers and combined with other forms of data.

Until digital video becomes the standard, video digitizers are available that allow computers to convert analog video signals into digital data for a variety of purposes. Some video digitizers can import video signals from televisions, videotapes, videodiscs, and other sources and display them on the computer's screen in real time&endash;at the same time they're created or imported&endash;along with computer controls and other graphic images.

Other video digitizers are designed to capture video sequences in real time and convert them into digital "movies" that can be stored, edited, and played on computer screens at a later time without external video equipment.
On-screen digital movies can add realism and excitement to educational, training, presentation, and entertainment software. But digital movies aren't practical for many applications because of their heavy hardware demands.

Data compression software can be used to squeeze redundant data out of movies so they can be stored in smaller spaces, usually with only a slight loss of image quality. But even highly compressed video clips gobble up storage space quickly. That's why most digital movies are currently stored on CD-ROM and other high-capacity storage media.

With video editing software, high-powered graphic workstations connected to sophisticated audio and videotape players and recorders can splice together scenes, insert visual transitions, superimpose titles, create special effects, add a musical soundtrack, and "print" a copy of the results on a master videotape. This kind of equipment is now becoming affordable for many consumers, opening up the possibility of a video desktop publishing revolution.

The Synthetic Musician: Computers and Audio:

Computers can store and process sound in a variety of ways.
Digitized Sounds as Computer Data

Any sound that can be recorded can be captured with an audio digitizer and stored as a data file on a diskette, hard disk, or other computer storage medium.

Sound data is sometimes called waveform audio, because this kind of editing often involves manipulating a visual image of the sound's waveform.

Recorded sound can consume large amounts of space on disk and in memory.

Sound data compression, like image compression, saves space, but it also compromises sound quality. Even without compression, memory-resident digital recordings lack the crystal-clear fidelity of compact disc recordings due to differences in sampling rate&endash;the number of sound "snapshots" the recording equipment takes each second.

CD Audio

Sounds are stored on CDs, not in the computer's memory. When the sounds are stored on CDs, software needs to contain only commands telling the CD-ROM drive what to play and when to play it. The sound quality is higher and the storage costs are lower.

Electronic Musical Instruments

Multimedia computers can also control a variety of electronic musical instruments.

A synthesizer is an electronic instrument that can create sounds ranging from traditional horns and woodwinds to otherworldly sounds that can't be duplicated with acoustic instruments. Synthesized sounds aren't recorded, they're created from mathematical formulas. A sampler is like a cross between an audio digitizer and a synthesizer. A sampler samples (digitizes) sounds from the real world, turns them into notes, and plays them back through a synthesizer. Most modern electronic keyboards use both synthesized and sampled sounds.

MIDI&endash;Musical Instrument Digital Interface&endash;is a standard interface that allows electronic instruments, regardless of type, manufacturer, or brand, to communicate with each other and work together. When outfitted with a MIDI interface, a personal computer can "talk" to MIDI musical instruments.

Music publishing software can turn a MIDI file into a musical score, ready for publishing.

Nonmusicians can use ready-to-play clip music MIDI files for multimedia productions.

Hypertext and Hypermedia:

Hypertext is an interactive cross-referencing system that allows textual information to be linked in nonsequential ways. A hypertext document contains links that can lead readers quickly to other parts of the document or to other related documents.

While the concept of hypertext has been around since at least 1945, hypertext first gained widespread public attention in 1987 when Apple introduced HyperCard. Many HyperCard-like programs appeared in subsequent years. Today the World Wide Web is the center of hypertext activity. Like HyperCard, the Web has inspired thousands of people to create and publish their own hypertext documents.
Because they can combine graphics, sound, and other media with text, HyperCard and the World Wide Web are often called hypermedia systems.

People who work with hypermedia today face several problems:

Hypermedia documents can be disorienting and leave readers wondering what they've missed.

Hypermedia documents don't always have the links readers want.

Hypermedia hardware can be hard on humans, who find that reading a computer screen is more tiring than reading printed pages.

Because they're computer based, hypermedia documents don't encourage scribbled margin notes, highlighting, or turned page corners for marking key passages.

The art of hypermedia is still in its infancy.

INTERACTIVE MULTIMEDIA: EYE, EAR, HAND, AND MIND

Today's multimedia computers allow users to work with information documents that intermix a variety of audio-visual media.

Interactive Multimedia: What Is It?

The term multimedia generally means using some combination of text, graphics, animation, video, music, voice, and sound effects to communicate.

Television and video are passive media. Modern personal computer technology allows information to move in both directions, turning multimedia into interactive multimedia. Set-top boxes may soon bring interactive multimedia to millions of televisions.

Multimedia Authoring: Making Mixed Media:

Multimedia authoring software allows you to create and edit interactive multimedia documents.
HyperCard is a simple authoring tool whose stack-of-cards metaphor is used by many other programs. A HyperCard document, called a stack, is based on the metaphor of a stack of index cards. Each screen, called a card, can contain graphics, text, and buttons&endash;"hot spots" that respond to mouse clicks. Usually clicking on a button (or a chunk of so-called hot text) transports you to another card&endash;the next card in the sequence, the previous card, a card far from the current position in the stack, or a card in another stack. HyperCard buttons can be programmed to perform a variety of tasks.

Rules of Thumb: Making Interactive Multimedia Work:

Guidelines for creating a simple HyperCard stack or a full-blown extravaganza include:

Be consistent.

Make it intuitive.

Keep it lively.

The message is more important than the media.

Put the user in the driver's seat.

Let real people test your presentation.

Interactive Media: Visions of the Future:

Interactive multimedia tools can give everyday people control over the media&endash;control traditionally reserved for professional artists, filmmakers, and musicians.
Many experts fear that new media possibilities will further remove many of us from books, other people, and the natural world around us.

KEY TERMS

animation, audio digitizer, bit-mapped (raster) graphics, bullet chart, button

clip art, color depth (bit depth), computer-aided design (CAD), computer-aided manufacturing (CAM)

computer-integrated manufacturing (CIM), data compression, digital image processing software , digital video

drawing software, frame, gray-scale graphics, hypermedia, hypertext, interactive multimedia

MIDI, morphs, multimedia, multimedia authoring software, object-oriented (vector) graphics

page-description language, painting software palette, pixel, pop-up menu, PostScript, presentation graphics software

resolution, sequencing software, synthesized sound, synthesizer, 3-D modeling software, video digitizer, WYSIWYG

Computer Literacy On-Line