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Multimedia Glossary
Select a letter for quick access to an alphabetical group of terms.
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What
is
Multimedia?
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to: info@webschoolsolutions.com
Acknowledgements
Awards: Rhodnar Top Quality Award:"Multimedia"
Last Updated: 10/10/00
Color resolution comparison.Acrobat - product from Adobe Systems, Inc. which converts text documents, word for word, image for image, into fully-searchable electronic documents. The electronic document, with the exact look and feel of the original but with added hyperlinks, is stored in PDF (Portable Document Format). The PDF document can be viewed and printed with the free Adobe Acrobat Reader.
The conversion process involves printing, from any word processor or application package, to an Adobe PDF Writer printer driver, rather than printing to a physical printer. The driver stops and asks where you wish to store the PDF document. Links, table of contents and other easy-to-create features are done with Adobe's Acrobat Exchange. A wonderful alternative to HTML.
Analog - waveforms, with valleys and ridges, referring to the natural form of sound/audio. To store/playback on a computer, analog data is converted to digital data. Analog-digital comparison.
ADC (Analog -to-DigitalConverter) - "recording" feature of sound cards that converts the analog/ sound waveforms to digital format, i.e. bits and bytes. This digital representation can then be stored, edited, processed and transferred between media. To playback sound files, the sound card uses a DAC (Digital-to-Analog Converter). The ADC samples the audio at very fast intervals ("sampling rate"), producing a stream of snapshots. When played back by the DAC at the same pace, the samples are perceived as sound.
Animation
- Drawn motion files, either in 2-D or 3-D. The animated gif
below was created using GIF
Construction Kit.
On the Web, HTML's push-pull animation is very low-end. JAVA, VRML (See Virtus WalkThrough 's "VRML assistant" feature.), DHTML, animated GIF's,Flash, and Shockwave are later adaptations/production tools for Web animation.
Animation, path - the animation software lets you specify a beginning position and an ending position, then calculates the positions in between.
Anti-aliasing - Process used to remove jagged edges in computerized graphics.
Anonymous - refers to a generic account username that any user can enter to log-in to a FTP file archive.
ANSI - the American National Standards Institute character set. Used in Windows-based programs. See related ASCII.
API (Application Programming Interface) - set of routines/functions
that an application program uses to request and carry out lower-level services
performed by the operating system. For Windows, for example, API's help
manage icons, windows, menus and other GUI elements.
See related - CGI and MCI.
Applets - small programs, called by application programs, that produce various special effects. WordArt, a Windows applet, lets you produce special effects with text. You can invoke WordArt by selecting Inset from the menu. See related JAVA applets.
ASCII - the standard character set for text files. See text files.
Aspect ratio - height-X-width proportions of graphics. Some programs allow you to maintain the aspect ratio when sizing a picture, i.e. when you change the width, the height changes proportionally so that the resulting image does not look distorted. See graphics.
Asynchronous communication - users communicate/interact, but at different times. These interactions may occur using e-mail, listservs or discussion boards.See Distance Education
Audio - sound, either synthesized (See MIDI) or digitized, for playback with a computer. File formats: .WAV - Windows, .AU - Unix, playable on both Macs and Windows machines with the right players.
Authoring software - programs used to create full, multimedia productions, such as simulations and tutorials. Although most of these programs have some point-and-click features to simplify development, most require some knowledge of programming language concepts. Popular authoring software packages include Asymetrix ToolBook, Microsoft Visual Basic, Macromedia Director and Authorware. FAQ's - Authoring Packages.
At the "lower" end, presentation software, like Microsoft PowerPoint, provide simpler ways to put multimedia into presentations. HyperStudio, sits somewhere in the middle: It provides more interactive capabilities than presentation software, but cannot do all that a fully-robust authoring package can do.
Typical authoring systems:
Binary file - a file that can only be read with special software, such as word processors or image viewers. Binary files contain special, embedded codes (i.e. program commands) that create bold or underlined text, for example. Text files, on the other hand, contain no embedded codes.
Bitmap - A windows format for storing graphics.
Blackbird - See Microsoft Internet Studio.
Blue book - CD designed for laserdisc use.
.BMP - See bitmap.
Browser - a program that lets you view Web documents. Browser comparisons.
Cascading Style Sheets/CSS - Cascading Style Sheets (CSS) is a mechanism for allowing web authors and readers to attach styles including fonts, colors, etc. to HTML documents. Authors can attach styles to their HTML documents whild readers may have their own personal style sheets.
Typically the styles are placed in the HEAD of the document, although
they can also be placed in the BODY and often are placed in a separate
file. The basic format of the STYLE tag is:
<STYLE TYPE="text/css">
HTML tag.class {special
formatting}
....
<SPAN> {special formatting}
</STYLE> (Source: Wayne's
World)
CAV - "Constant Angular Velocity", as applied to laser discs, permits 30 minutes of recording per side and allows the user to address each frame separately. Contrast with CLV.
CBT - Computer-based training. Used synonymously with computer-assisted training (CAI).
Capture, video - Video capture cards let you record/digitize pictures for use with a computer. The pictures may be still-images or movies. Once captured, the picture data is compressed using a CODEC, with playback requiring CODEC-decompression. Intel's Smart Video Recorder board, an excellent capture card, can compress video real-time, or "on the fly", provided you have a fast machine and lots (and lots) of defragmented storage.
CD's - Glossary of CD and DVD Technologies
CD-DA - a music CD. See related Red book.
CD-i - Compact Disc-Interactive, developed by Phillips/Sony, includes audio, full-screen video and interactive capabilities. Follows ISO's "Green book" standard.
CD-R (Recordable CD-ROM, CD-Recordable) - Software/hardware needed to create your own CD's - for backup/archive, catalogs and other large documents, and multimedia! To begin the process, you "pre-master", that is, you use pre-mastering software to decide what data to include on the disc and its best disc arrangement for efficient retrieval. Once pre-mastered, you record. See related:ISO 9660 format.
CD-ROM - Compact Disc Read-Only Memory. From single-session, single-speed units, CD-ROM drives are now multi-sessioned, and read information 2X, 4X, 6X, 8X and 10X times as fast as original music CD players. Computer CD-ROM drives can slow down to single-speed to play music CD's: In a pinch, you can play music CD's with Windows' Media Player (Use the Control Panel to add the needed driver/), although typically you would use the software that comes with the CD-ROM drive.
CD-ROM "hybrids" - CD-ROM's with embedded Internet links. Although the Web can provide current information, i.e. timely updates and corrections, it lacks the bandwidth to deliver large multimedia files quickly. The "Internet-enabled" CD-ROM, or "cybrid," is being touted as a software solution that will use the strengths of both technologies. The parts of a program that can slow down access time if downloaded from the Internet (multimedia, index searches) are kept on the CD-ROM for faster loading. The Internet side of the equation is used for providing, and for adding new features without the need to send out a new CD-ROM disc. In the near future, look for hybrid DVD's.
CD-ROM servers - devices, like towers, changers and jukeboxes, that allow you to put CD-ROM's on networks: one CD, rather than multiple copies, serves many users. CD-ROM towers stack multiple drives, sometimes as many as 40, in a single box. Each drive has a read head for its CD, making access fairly fast. CD-ROM changers swap CD's in and out of the ONE drive. The jukebox, the changer's "big brother", can store up to 2,000 CD's and can be as big as a refrigerator. The swapping action can slow CD access, especially for changers. For an interesting Web site, see: SIGCAT (Special Interest Group on CD-ROM Applications and Technology)'s report on jukebox performance.
CDROM-XA (Extended Architecture)- the standard for pressing CD-ROM disks (See CD-R), which interleaves audio and digital signals for playback on the computer.
CD-RW, CD-ReWritable - an erasable CD-ROM, called CD-RW, or CD-ReWritable. Backers of the new technology say that erasable CDs will become a flexible new storage solution, holding 450 times more data than a typical floppy. Critics point out that CD-RWs can't be played on most of the currently installed CD-ROM drives. CD-RW drives will appear in the first quarter of 1997, and eventually will replace today's CD-ROM drives. Hewlett-Packard hopes to market a temporary solution called "MultiRead" to enable all new CD-ROM drives to handle CD-RW discs. CD-RW technology differs from CD-Recordable (CD-R) technology, which can be recorded on only once. If a mistake is made, the disc is worthless. Meanwhile, the new DVD (digital video disc) drives that will be coming out next year will be able to handle CD-RW discs. (Investor's Business Daily 22 Oct 96 A8)
CGI (Common Gateway Interface) - server-side programs, running at the request of the client, that typically perform interactive Web actions. Normally, servers "serve" the content of static files (html, images, movies, sounds). In CGI, clients request a program to be executed and its results to be returned, as in database or search applications. All form-processing requires CGI. (in-depth look)
Client - Any computer connected to a host computer, or the software used to connect to the host. See also: host.
Client/Server - set of computer applications (programs) in which two or more computers work together. Server(s) store data and programs, which they deliver on request to clients. Part of the processing is done on the client, while the server concentrates on storing and delivering the data to be processed. This interaction between the client and server occurs in the background, so users are typically unaware which computer handles what.
Clip art - collections of pictures/photographs. Many application programs, such as PowerPoint, contain built-in clipart.
CLV - "Constant Linear Velocity", as applied to laser disks, where 60 minutes can be recorded per side. CLV discs cannot display an individual frame. Contrast with CAV.
CODEC - program/device that COmpresses/DECompresses digital video. xxx Cinepak and Indeo (Intel) are examples of CODEC's. See CODEC Central for an in-dept look at CODEC's.
Color Palette - available color selections, ranging from 16 colors to 16.7 million. Color resolution comparison. There are often color shifts from machine to machine that can have "unfortunate" results. See related: dithering. Macintosh and Windows share only 216 out of 256 colors.
Compression (file) - Process for reducing file size, often called "zipping" or "archiving". The resulting, compressed file can be from a single, large file or can contain several files that have been squeezed into a single file. The many-to-one compression makes file group identification, copying, and transporting faster and easier.
Compression (video)- Process which reduces the number of bytes required to store/transmit digital video. Typical schemes involve comparing frames and coding-out, or eliminating, inter-frame and intra-frame redundancies. The compression may be done by software, hardware or a combination of the two. On playback, the data is decompressed. See CODEC.
Why compress video data? To reduce storage space and to playback faster. A full-screen (640 x 480 pixels) image with 16.4 million colors takes up 1 Mb of memory. For full-motion, the computer needs to display 30 pictures/frames per second, thus requiring it to "shuffle" 30 Mb of data every second. Storing 10 seconds of video would require 300 Mb.
Jan Ozer, President of Doceo Publishing, is the foremost authority on digital video/CODEC's.Compression, Lossless - digitized video containing ALL the original video information.
Compression, Lossy - digitized video which, to save space, does NOT contain all the original video information.
Cookie - A "cookie" is a small piece of information, a virtual "sticky note", sent by a Web server to be stored, by your browser, on your hard drive. The cookie stores information about you and can be retrieved by the Website each time you visit there. Without them, sites would not be able to retain information about individual visits; thus, cookies store "state information." Cookies are passive files, typically used in .asp (Active Server Page) programming, and should not be confused with server-side databases that collect personal information you've voluntarily (or unwittingly) submitted. See Cookie Central
Cross-platform - Files usable/executable with different operating systems. For example, Virtus WalkThrough, a 3-D animator program, can produce "cross-compatible" animation files for Macintosh and DOS/Windows machines. "Power" Mac's let you change to the PC work-mode; "power" PC's can handle Macintosh software/files.
Copyright - exclusive ownership of a created work. Given the Web's openness, who owns what? See: @rtED Links
CU SeeMe - A leading desktop videoconferencing software package. Free download.
Cyberculture - "a collection of cultures and cultural products that exist on and/or are made possible by the Internet, along with the stories told about these cultures and cultural products." See Resource Center for Cyberculture Studies (RCCS).
DDE (Dynamic Data Exchange) - Windows' process that supports exchange of commands and data between two application. OLE is a DDE enhancement.
DLL (Dynamic Link Library) - a Windows' code module that is loaded and linked at runtime, then unloaded when it has finished executing.
.DIB (Device Independent Bitmap) - a Windows graphics file format. Image File Formats
Digital/digitalization/digitized - process of converting video or audio signals, normally in waveform, into 1's and 0's. This digital format (actually patterns of on's/high-voltage (1's) and off's/low voltage (0's) rather than digits) can be processed by a computer. Analog-digital comparison.
Digital Signal Processor - A separate processor, built into some sound cards, that offloads/relieves audio processing from the computer's CPU.
DVD's - Glossary of CD and DVD Technologies - a new standard for recording video on CD-ROM's using MPEG2, thus boasting better-than-broadcast TV quality. Costing about the same as a CD, DVD-ROM's hold 8 to 40 times more data. Sony/Phillips and Toshiba/Time, the two major developers, predict DVD will replace videocassettes, laserdiscs, CD-ROM's and audio CD's. Recently (June '97) Hitachi announced a re-writable DVD, which may spell the end to re-writable CD's.
Digitizing tablet - pen-based input system, resembling a sketch pad. The pressure of the pen on the tablet is translated in electronic dot patterns. Many delivery companies, such as UPS, use tablet technology to record signatures upon package receipt. President Clinton used a Wacom graphics tablet and pen to sign the Telecommunication Reform Act of 1996. See "Graphics Tablets Make Mouse Calls", Presentations, April 1996, for a good review.
DirectX - 3D graphic programming API written by Microsoft. Allows programs to interface with and use built in high speed 3D graphic routines on graphic cards. Built into Windows 95 and 98.
Distance Education/Learning - instruction that takes place when the student and instructor are separated by physical space and/or time. Correspondence courses provide one type of "distance learning". Networked computers, especially those linked into the Internet, provide many remote education opportunities. In fact, you can now obtain a degree from a "virtual university."
In North Carolina, there are three major "forces" in distance learning:
DLP - Digital Light Projectors. Contrast with LCD Projectors.
Dot pitch - the distance between the pixels on the monitor. The smaller the distance, i.e. the denser the pixels, the clearer the picture resolution.
Downlink - transmission of a signal from a satellite to a receiver on Earth.
Download - process of transferring a file from system to another.
Drivers - software, typically ending in .DRV in Windows systems, used to 'talk to' or manage hardware, like sound cards, printers ...
Dropped frames - In digitial video, when the computer cannot keep pace with the displayed images, it drops frames in an attempt to catch up.
DSP (Digital Signal Processor) - a special processor, additional to the CPU, that is dedicated to processing real-time audio and video signals. For example, the DSP chip on a sound card lets you add echoes, reverb and other special effects.
DVC - Desktop videoconferencing
Dynamic HTML/DHTML - a set of recent technologies (HTML, layers, Cascading Style Sheets, Javascript) which, togehter, enable richer, more interactive content. See: Netscape Developers' Edge Online and a local production done with Macromedia Dreamweaver.
An e-mail address has two parts, separated by @ .The portion before the @ sign is the username, or mailbox name, of a particular user. The portion after the @ is the location adress. The suffix, in this case .gov, denotes what type of organization.
Example: president@whitehouse.gov (By clicking, you can actually send the President some email.)
EPS (Encapsulated Postscript) - graphics file format often used in desktop publishing packages, like PageMaker.
Ethernet - A local-area network (LAN) standard.
File Formats - for graphics/images, movies, sounds/music, text
File Transport Protocol (FTP) - FTP is an acronym for File Transfer Protocol and is a method for retrieving files from a remote Internet site. Many sites out there allow what is termed an 'anonymous' connection. In other words, there exists a special username called 'anonymous' so that the site can act as a library of useful public domain programs and documents.
Firewire (IEEE-1394) - emerging serial interface technology that allows connection of devices at speeds up to 50 Mbytes/s. Used for devices such as video cameras so that they can feed real time video to a computer. Also allows devices to be hotswapped (added and removed without rebooting).
Flash - a product from Macromedia (as is Shockwave) that produces interactive vector-based animations called "Flash movies". Like Shockwave movies, Flash movies are intended for web-based distribution to web browsers. Netscape ships with the Flash plug-in. +/-'s of Flash
.FLC - An animation or moving picture file format originally created by Animator Pro. FLC files contain one or more frames, so you can see animated pictures from the screen when you display these files. A "FLC" file has an extension .flc.
.FLI - FLI files are also animation files. Although a FLI file's structure is very similar to that of a FLC file, they are different file formats. A "FLI" file has an extension .fli.
FM Synthesis - low-end sound cards create computerized tones using FM - "frequency modulation". The result sounds very unmusical, computer-generated. FM synthesis is being replaced by more lifelike technology called wavetable, where sounds are created from actual recordings of instruments.
Font - a complete set of characters for one style/typeface, including all the letters, numbers and punctuation marks. For example, Times New Roman or Arial.
FPS - frames per second - the number of picture images displayed per second, giving digital video the illusion of motion. Full-motion video, with no dropped frames, is considered 30 fps (NTSC standard).
Frame - a single picture in a computerized "movie"/digital video.
Frame grabber - video capture card that captures a single frame from a video stream and stores it as a still image.
Frame rate - number of images per second displayed in a stream of video. 30 fps (see above) is considered full-motion, television-quality video.
Freeware - The software author retains rights to the program, but allows users to copy and use the program without fee. The program thus cannot be resold or relabelled without the consent of the originator.
Full-motion video - digital video running at 30 fps (NTSC - US standard). It does not necessarily fill the screen.
Full-screen video - digital video filling the entire screen (use 640 x 480 pixels) for typical graphic, not just a smaller window. Typical video window sizes. See related: Graphics/Resolution for the Web
Get-a-date - cyberdating. Leave an audio messsage for a Web Personal.
GIF (Graphic Interchange Format) - a graphics file format originated by Compuserve, usable for Web pages. Use PaintShop Pro to convert other graphics file formats to .GIF format.
provide a
method for adding animation to web pages.
Gopher - A menu-driven system that lets you search for and retrieve files across the Net.
Graphical User Interface (GUI) - A computer interface using point-and-click mouse actions (rather than the keyboard exclusively) and pictures (rather than text exclusively). Windows, Macintosh, Netscape and Mosaic are examples of GUI products.
Graphics - Images are typically vector (object-oriented) or bitmap (rastor). See below Graphics, Bitmap and Graphics, Vector. After reading their definitions, test yourself.
File formats include: IMB, DIB, GIF, MTX, PCX, TIF, TGA, BMP, WPG, JPG, CUR, CO. (See Image File Formats) PaintShop Pro can be used to convert to/from various formats. Its help menu provides full definitions for all graphics file formats. PaintShop Pro maintains the aspect ratio of pictures when sizing, thus can reduce sizing distortion.
Graphics, vector - Graphics consisting of objects, each of which can be separately manipulated - e.g. sized, moved, (un)grouped, positioned to the back/front. The graphic components are calculated, hence can be sized without distortion. File formats include: AutoCAD DXF, CBM, EPS, HGL, PIC, DRW, WMF, WPG.
Graphics Accelerator - a graphics card, used in animation production/creation, that speeds the display/preview of 3D animation.
Graphics Tablet - see digitizing tablet.
Green book - format for CD-i.
High Sierra - ISO 9660: a format for placing files and directories on CD-ROM.
Hit - A match to the criteria you specify in a search.
Home Page - the start-up page for Web documents.
Host - A computer that acts as a file server. Users at remote computers (i.e. client computers) are allowed to access information that's stored on the server, or host computer. See client.
Hotlist - a list of frequently-accessed Web documents. Fun spots!
HTML - HyperText Markup Language - the most commonly-used Web programming language. HTML codes are document formatting codes that tell browsers such as Mosaic or Netscape how to display the document you see on the screen. Free HTML software tools.
HTTP - HyperText Transfer Protocol - the set of language rules Web users must follow to communicate with each other. The phrase World Wide Web refers to the collective set of servers (computers) speaking HTTP.
Hypermedia - "hypertext" with links not only to text, but also to other forms of media - sounds, graphics, movies/video, animation.
Hypertext - "text" which allows users to "hyper-jump". Hypertext is basically the same as regular text, with one exception: hypertext contains connections within the text to other Web documents. The connections are denoted, generally, as underlined, colored text. The "documents" to which the hypertext connect may be local or remote, perhaps even in a different country.
Image File Formats - .GIF, .JPG, .BMP, .PICT ...
Indeo - Intel's CODEC for video.
Internet - "The network of networks" . The Internet originally developed out of the ARPAnet. The ARPAnet model specifies that communication occurs between the source and destination computer in small parcels of data known as Internet Protocol (IP) packets. Each computer transmitting a packet has the responsibility of addressing and delivering it to the destination computer. Berkeley Systems adopted the IP networking system in their version on the UNIX operating system and over the years added many extra network oriented commands to the operating system. Before long, because of the device independence of this protocol, many different vendors adopted the IP system.
In the late 80's, the National Science Foundation (NSF) created five super-computer centers. They decided to link these centers using the IP protocol as a method of sharing the expensive resources. Academic institutions soon connected their local networks to the central NSF network backbone to be able to access the supercomputer resources. The collection of inter-connected networks became known as the Internet.
Today the Internet has become a global "information highway", connecting almost every country in the world together. Anyone with a computer, modem and the money (or opportunity) to connect into an online service provider (like America Online) can tap into the "network of networks." The World Wide Web (WWW) is one of the most popular Internet services.
Internet Studio - a Web programming "language", developed by Microsoft, that uses drag-and-drop and OLE - not HTML - to publish Web pages. Internet Studio will support numerous file formats and software programs - VRML, Macromedia Shockwave, Adobe Acrobat, GIF, JPEG, Microsoft Office (Word, Excel, PowerPoint, Access), among others.
Intranet - The World Wide Web documents accessible within a single organization.
Internet Protocol (IP) - the protocol which provides addresses needed to move packets of information across networks. IP addresses have two parts: a network identifier and a host identifier. See also TCP/IP.
ISDN (Integrated Services Digital Network) - a network/telephone connection that transfers data at rates more than 4 times faster than a 28.8Kbps modem. Ordinary modems (non-ISDN) convert computer data to audio tones/analog to transfer over the phone lines. ISDN "modems" connect digitally: Inherently faster digital signals rather than tone signals transfer over the lines. Network transfer speed comparison
Basic Rate ISDN, often called "2B+D" or BRI, arrives on 3 channels - one Delta ("D") 16 Kbps channel carrying telephone signals and two "Bearer" ("B") channels delivering data at 64 Kbps. Primary Rate ISDN, also known as T1 service, has 23 B channels and one D channel, delivering at a rate of 1.544 Mbps (T3 transmits at an extremely high rate - 44.7 Mbps).
ISO - International Standards Organization
ISO 9660 - a format for placing files and directories on CD-ROM. Readable by both Macintosh and PC-compatible computers.
JAVA Applets - small programs written in JAVA that produce various special effects, which are embedded right into the Web pages. When someone accesses a Web page with applets, the applets automatically download with the page: All that is needed to view the effect comes with the page itself, making applets independent of the eccentricities of various operating systems. This design feature makes applets particularly desirable for multimedia applications, which typically are very platform-dependent.
JavaScript - resembles Java (much easier to learn), but runs (is interpreted) on the client (user) side, not the host/server. (simple code example) +/-'s of Javascript
Jewel cases - plastic carrying cases for CD's.
JPEG (Joint Photographic Experts Group) - compressed, still-image graphics files. There are two major types of JPEG - progressive, where a fuzzy images emerges into 100% decompression/clarity, and baseline or standard, where a clear image is revealed, part-wise, top-down. Progressive, or interleaved, decompression looks better over networks. See CODEC.
Jukebox - see CD-ROM server.
Key frame - a "complete" video frame, containing all the image detail, not just the changes from the previous frame.
Kiosk - an electronic "newstand" or booth. Electronic kiosks are often used for mall directories, where users can touch a screen to find the location of a particular shop.
Kodak Photo CD ("PCD's") - Photographs/images
are "printed"/digitized on CD's. Your Photo CD comes with a contact
sheet, showing small pictures of each image on the disc. You can keep
adding pictures to the CD. To view the CD images, you need a viewer. Nowadays,
many multimedia programs can import these already-digitizied image files
into documents.
Laserdisc player - Like a VCR, this device plays back analog video stored on laserdiscs.
LCD - Liquid Crystal Display panels connected to computers allow the display to be projected on a screen. Always get an active-matrix LCD. If you have a monitor with a video-input, you may be able to use a scan converter as a less expensive alternative to LCD-projection of computer data.
LISTSERV / Mailing Lists - Mailing lists or list servers are a one to many electronic mail conferencing system. Once subscribed to a list, the subscriber receives electronic mail messages from all contributing members of that list. A subscriber can mail to the list e-mail address and the message will be distributed to all subscribed members.
There are a number of different types of lists. An open list is one in which any person with an e-mail address may subscribe and be a part of the conference. A closed list is one in which the list owner will approve or not approve any subscription request. For example, a list may be very specific to a certain profession or group that you must belong to before subscribing. A moderated this is one in which the entries are reviewed by the list owner before being mailed out to the subscribers. The list owner may in fact choose to make a digest out of the submissions, and then post that to the list server. An unmoderated list is one in which all mail coming to the mail server is distributed regardless of the content.
Lossy/Lossless Compression - See compression.
Luminance - a color's brightness.
MCI (Media Control Interface) - multimedia commands/calls comprising Windows API (Application Program Interface).
Micromoney - proposed Web-payment scheme where funds are subtracted from your bank account when you buy digital tokens. You then spend this encrypted micromoney at participating Web sites without the hassle of a credit card transaction. Ecash and CyberCash are two such digital-cash schemes.
MIDI (Musical Instrument Digital Interface) - Rather than recording sounds, MIDI instruments/software record finger action - what note is being played, when, and for how long. To playback MIDI files, you need a sound card that can interpret the MIDI note data, either by creating the tones themselves (FM-synthesis) or playing back sounds that are stored internally (waveform). "General MIDI" is an emerging standard for MIDI playback. Alphabetical listing of MIDI works by classical composers.
MMX - (Multimedia Extension), a multimedia accelerator in Intel's Pentium processors that speed media and communications processing 40 to 60%. Standard Pentiums move 1 byte of data at a time into the CPU for processing. In contrast MMX Pentiums move 8 bytes, all processed simultaneously. The catch? Not all application programs, as yet, have been written to take advantage of the specialized instruction set for the MMX's, hence you see no performance improvement for most programs currently on the market.
Modem - a hardware device that converts waveform (analog) data to digital. MOdulation converts analog to digital; DEModulation converts digital to analog. Hence, MODEM. Network transfer speed comparison.
MOOs, MUDs, MUSHs -
MOOs are internet accessible, text mediated virtual environments well suited for distance learning. MOOs of interest.MPC / MPC2 / MPC3 (Multimedia PC) - industry standard for a "minimal" multimedia computer system. (Now outdated; of historical interest)
On June 12, 1995, the Multimedia PC Working Group, an independent special interest group of the Software & Information Industry Association, released the latest standards for multimedia equipment. The MPC3 "does not replace MCP2. It takes multimedia a step further, opening the door for new applications and a vastly improved multimedia experience." Software titles that run under MPC and MPC2-compliant hardware will also run on MPC3-compliant hardware.MPEG (Motion Picture Experts Group) - a hardware CODEC for compressing video files.
Multimedia - What is multimedia?
Multi-session - a CD-ROM drive that can read CD's that have been updated/changed. As CD's are updated, new directories are written, with the newer directories written further and further out to the edge. Multi-session CD-ROM drives begin searhcing for directories by reading out to in, thus can find the furthermost directory. Single-session CD-ROM drives begin searching for directories from the inside out, thus only the first directory nearest the hub would be encountered.
Multi-thread - describes a program that is designed to have parts of its code execute concurrently.
Newsgroups - A newsgroup is like a bulletin board: any subscriber can post a message to the newsgroup, and each subscriber can read any or all of the messages. Newsgroups can be useful for gathering information on subjects that are popular among other Internet users. The most active newsgroups are usually those focused on high-tech topics, topics of concern to academics or students. However, newsgroups devoted to entertainment and non-technical professional topics often have a significant number of regular participants. You can read news using the Netscape browser, or through a variety of news reading programs.
NTSC, PAL, SECAM - NTSC is the standard for video signals in the US, Japan and Canada. NTSC uses 30 fps. PAL and SECAM are international/European standards, using 25 fps.
OCR (Optical Character Recognition) - scanning/process for machine print recognition. Compare to ICR.
Object-oriented - a programming technique that focuses design on the data (=objects) and on the user interfaces to it.
OpenGL - 3D graphic programming API written by Silicon Graphics. Allows programs to interface and use built in high speed 3D graphic routines on graphic cards. The standard for high end 3D modeling and recently adopted by Apple Computers as their standard 3D interface.
Optical Storage Unit - CD-ROM drive.
Orange book - Standard for WORM (Write Once Read Many) CD's. Used for archiving/backing up catalogs, directories and other computerized paperwork.
PAL - video format used in Australia and western Europe.
Parallel Ports - also called "printer ports", parallel ports transfer several bits simultaneously. Thus, they are faster than serial ports. However, they can only send, not receive, information; whereas serial posts can handle 2-way transmission.
PCI - Peripheral Component Interface, very fast I/O bus (with potential of 132 Mbps transfer rate).
PCMCIA - Personal Computer Memory Card International Association.
PDF - Adobe Acrobat's Portable Document Format.
Pixels - PICture ELements = Pixel. The tiny dots comprising a picture. Look closely at your TV to see pixeled images.
PNG - standing for "Portable Network Graphics" and pronounced "ping", is a proposed replacement/improvement for the GIF format. It allows for both up to 8-bit and 8x8x8 palettes, variable transparency, gamma correction, better interlacing and better compression than GIF. It does not, however, allow for animation. PNG has only recently seen support from Netscape and IE, neither one supports the PNG standard fully, though plug-ins are available for most platforms to allow both browsers to be more PNG compliant. Macromedia's Fireworks uses PNG as its native format. See: http://www.libpng.org/pub/png/
POTS - "Plain Old Telephone Service", analog telephone service
Polyphony - the total number of sounds a sound card can reproduce at the same time. A 32-note card can play 32 notes at a time. See wavetable and FM synthesis. See also MIDI.
Presentation software - Packages, such as Microsoft Powerpoint, which allow users to create "electronic overhead transparencies". Typically easy to use, presentation software does have all the full multimedia capabilities that you will find in authoring software.
Typical presentation systems:
Public domain - software is available for unrestricted use, and can be copied freely and even renamed and resold.
Push Web technology - Also referred to as "Web-casting" or "channel-casting", this technology publishes/broadcasts personalized information to subscribers. Then, instead of using bookmarks and search engines to pull down information, users would run a client application that gets updated with data that is "pushed" down by a server.
RAID - "Redundant Array of Independent Disks", stacked hard drives.
RAM - "Random Access Memory" - cache RAM (fast RAM to match the
speed of microporcessors); flash RAM (fast, permanent memory on PCMCIA
cards); DRAM (dynamic RAM); SRAM (static RAM) ; SDRAM (synchornized DRAM);
VRAM (video RAM); CDRAM (cached DRAM) ... RAMbo
RealAudio - real-time, live audio on the Web. RealAudio highly compresses sound files to ship down the network. After front-loading a portion of the recording, the receiving player starts, pulling in remaining portions. This lets users begin listening as the sound file is being downloaded, hence "real-time", rather having to wait until downloading is complete. You can take a closer look/"listen" at http://www.real.com.
RealVideo - delivers "broadcast-quality" video over the Internet in real-tim. The software operates over modems operating at 28.8 Kbps and up. The beta version is available at http://www.real.com.
Real-time compression - compression of movies as soon as they come into the computer - also known as one-step capture. See capture, video.
Resolution - the clarity of the displayed/printed image. The more pixels/dots per square inch (dpi), the finer the detail (higher resolution). Color resolution comparison
Resolution, Graphic Considerations for the Web
RGB -Red-Green-Blue, the primary colors composing light. Applied to color monitors, for example.
RIFF (Resource Interchange File Format) - file format for storing sound and graphics so they can be played by different types of computers.
RLE (Run Length Encoding) - Microsoft's CODEC used for no more than 256 colors.
Sampling - When coverting video or audio waves to digital format, digitizing software picks out points along the wave and records or "snapshots" these points. These "snapshots" can then be replayed in much the same way that motion pictures are recreated from the individual frames. The higher the sampling rate, i.e. the more snapshots/points, per unit time, the more accurate the computer's representation of the wave.
Scan converter - See Video Scan Converter.
Scanner - computer device which "reads" text or graphics and converts them into digitized documents/files. Most scanners work by lighting an image and measuring the light reflected through it. The scanner them converts the reflections into distinct voltages which are, in turn, transformed into patterns of dots. The resolution or clarity of the image is measured in dots per inch. See related: Resolution, Graphic Considerations for the Web
Screen saver - a visual program using moving graphics to prevent monitor burn-in.
SCSI - "Small Computer Systems Interface" , a very fast, versatile parallel port allowing a computer to connect (or "daisychain") up to 7 peripheral devices, like laser printers, CD-ROM drives.
Search "engines"/tools - programs which allow you to search through Web pages by keyword or subject. See: Webmaster's Guide to Search Engines
SECAM (Sequential Color with Memory) - video format used mostly in France.
Self paced - the student can start and finish the program at any time, at his/her convenience. It typically involves no moderation/interaction with an expert/instructor. Examples include most cd-roms, video-tapes, cassettes, etc. See Distance Education
Serial Ports - used for 2-way communication, serial ports transfer data one bit at a time. Many devices, including modems, scanners and laser printers, connect to serial ports. Contrast to parallel ports.
Server-Side Includes(SSI)
Server-Side Markup (SSM) - a "tag" embedded in the Webpage that gets interpreted "on the fly"/processed by the server each time the page is requested. For example, a "last modified" time/date stamp, e.g. producing Monday, 12-Apr-1999 08:00:16 EDT, is done with the tag <!--#flastmod file="name_of_file.htm"--> (an in-depth look). Related: Active Server Pages, Cold Fusion
Shareware - "try before you buy" software. The author retains full rights to the package. It may be copied at will, but shareware cannot be used at will. There is generally a limited period of use granted without fee, commonly 30 or 60 days. After that period, the user pays a licensing fee to continue using the software.
Shockwave- add-in to MacroMedia Director that lets you create highly-compressed interactive animations and movies for Web pages. Director supports Java applets. (in-depth look) An easier-to-use, vector-based Web-animation program is Flash, also from Macromedia. +/-'s of Shockwave
"Sneaker" Net - when all electronic file transfers fail, files are saved to floppies, zip disks or some other removable storage medium and walked or mailed to the destination.
Sound Blaster-compatible - works with software written for the Sound Blaster video card, THE sound standard.
Sound card - An add-in circuit board that once installed, enables the computer to accept audio input from a microphone, edit/trim/mix recordings, play sound files stored on disks or CD-ROM's, and produce audio output through speakers or earphones. For output, sound cards can 1) create or synthesize sounds, like a keyboard/synthesizer, and 2) play previously-recorded sounds, like a tape recorder/player. See also audio.
Streaming Audio/video - capability to begin playing media onthe client side before it has fully downloaded from the server side, i.e. begins playing as it is coming in, " in real-time." The major players are RealNetworks (RealAudio - the industry standard), Microsoft (Netshow - avoid this!) and Apple (" streaming" QuickTime). +/-'s of streaming media (an in-depth look)
Synchronous - communication/interaction in real time, i.e. at the same time, thus lending itself to the kind of immediacy of communication experienced in a classroom. This may be done using the telephone, chat rooms, whiteboards, etc. See Distance Education
Synthesized - sounds created by computer circuitry. See wavetable and FM synthesis. See also MIDI.
SVGA (Super-VGA) - video monitor/card supporting 640x480 resolution (or greater) with 256 colors or more.
Teleconference - a phone meeting where callers can both see and hear each other. Network transfer speed comparison. See also: videoconferencing.
Text files - Files that contains no special codes or commands - such as bold, italics or graphics - only text. Text files, unlike binary files, can be read without any special software. See binary files.
Tool - program, following defined protocols, that provides a service.
Text-to-Speech - voice synthesizers that "read" computer text. First used to read screens for blind computer users, text-to-speech is becoming increasingly popular for children's games. For more information: Visit AT&T's Advanced Speech Products Group (http://www.att.com/aspg)
TIFF (Tagged Image File Format) - cross-platform file for storing high-quality graphics.
Tool - program, following defined protocols, that provides a service.
Touch screen - monitor input where you can use your finger to draw on a screen or select an on-screen object. Touch screen technology is often used in ATM machines or in malls, for example, in electronic information kiosks/directories.
Trackball - Operating like a mouse, a trackball remains stationary while a ball on its top is rolled with the fingers. Because you don't move it around the desk/mousepad like a mouse, it takes up less space.
True-Type - Window's built-in "outline" font technology. It works by taking a mathematical description of a font's outline and using it to "paint in" on-the-fly screen and printer representations. The printed appearance is true to the displayed appearance, hence "true-type". True-type fonts are stored in two files, with the extensions .TTF and .FOT. To install a TTfont, copy the .TTF file into the directory where the font files are stored (C:\WINDOWS\SYSTEM). Then use Control Panel to ADD the font: Control Panel creates the .FOT file and adds a line to WIN.INI that enables Windows to initialize the font at start-up. A typical font-entry looks like:
USB (Universal Serial Bus) - Serial interface that allows connection of up to 127 devices at speeds of either 1.5 or 12Mbits/s. It supplies power for those devices and allows the devices to be hotswaped (added and removed without rebooting). Currently used to connect keyboards, mice, printers and scanners.
VGA - video monitor/card supporting 640x480 resolution with 16 colors. (Also covers resolutions of 320x240 with 256 colors.)
Video Scan Converters - Convert computer RGB signals to NTSC, PAL or SECAM video signals. Once converted, these signals may be videotaped or shown on a television monitor.
Video, analog - True full-motion video from laser discs, videotapes. Formats: Hi8, 8mm, S-VHS, VHS
Video, component - Used in Hi8 and SuperVHS cameras, component video splits the single composite video signal into colors (RGB) and improves the quality by adding a luminance or brightness (Y) channel and a color/chroma intensity (C) channel. Superior to composite video.
Video, composite - single-signal video, used in VHS. Inferior to component video.
Video, digital - Digitized video, i.e. video converted/compressed to file format. Formats: .AVI (Video for Windows) and .MOV (QuickTime - cross-platform for both Macintosh and Windows).
Video RAM - special memory chips residing fast video cards. The more memory, the higher the resolution. For example, to put out 256 colors you need 512K of video RAM; for 16.7 million colors, you need 2 Mb. (See VRAM).
Videoconferencing - transporting real-time voice and video over telecommunications services. Nowadays, "Web conferencing" is the fashion, thanks to various desktop videoconferencing (DVC) products like Enhanced Cu-SeeMe.
Voice recognition - software which recognizes spoken commands. Most software has to be individually trained for each voice, making its general usage limited. For a good example of voice-recognized commands, dial 1-800-ATT-COLLECT.
VRML - Virtual Reality Markup Language, the "next stage" in HTML, permitting 3-D animation browsing. The VRML server works by transmitting an object command, such as "cone", and the mathematical description of its dimensions, location, color and texture to the client. The client then handles rendering and manipulation. See: http://www.vrml.org/. Free VRML tools
Wavetable - sound synthesis using a built-in selection/table of actual recordings. The output is more realistic than that produced by the older technology, FM synthesis.
Whiteboard - document-teleconference function that lets multiple users simultaneously view and annotate electronic documents with pens, highlighters and drawing tools.
World Wide Web (WWW) - provides the glitziest on-line information on the Internet. The Web or WWW or W3 or WaWaWa, as it is familiarly called, consists of a system of pages where the information is linked together like hypertext. As you click on each underlined word, it takes you to the next page of related information, and so on. In the Web, however, the links jump from one information source to another, where the sources may be in different countries.
WORM - (Write Once Read Many) CD's. Used for archiving/backing up catalogs, directories and other computerized paperwork. See Orange book.
XML - (Extensible Markup Language) XML is younger sister to hypertext markup language (HTML). The difference is that XML is a "metadata language", i.e. it carries information about information. XML allows reuse of learning objects, and assembly of objects on demand as a learner asks for information. XML also allows the same learning object -- for example, a definition with a test question about the definition -- to change with context. Some sites to check for information about XML include:
Zip drives - Removable, floppy-disk drive alternatives. Iomega's (http://www.iomega.com/) zip (low-end) and Jaz (high-end) disks accommodate 100MB and 1Gb of storage, respectively. The drives cost about $200 and $500, respectively, and individual cartridges cost $20. With speeds close to hard disk rates, zip/jaz cartridges/drives can replace hard disks for many uses, including large video file storage.
Special thanks to Larry Hinsley - lhinsley@intrex.net
Created and maintained by Lane
Price Rose
