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n. An umbrella term for Microsoft products that enhance Internet usage by providing a substantially "slimmed down" infrastructure to enable controls to be embedded in Web sites and respond interactively to events. Most Web users will experience ActiveX technology in the form of ActiveX controls, ActiveX documents, and ActiveX scripts. ActiveX allows a variety of pre-built functions to be activated within intranets as well as on the Internet.

ActiveX control
n. A compiled software component that encapsulates a set of business or user interface functions. An ActiveX Control is used to provide user interface components and is designed to run on the client computer. ActiveX Controls can be embedded in Web pages for use over the Internet as well as combined to create client/server applications that run over a corporate network. They can be created by a variety of programming languages from Microsoft or from third-party vendors. ActiveX Controls use the file extension .ocx. See also controls and events.

ActiveX component
n. A compiled software component that encapsulates a set of business functionalities. The ActiveX Component can execute either on a client computer or on a server computer, transparent to the calling application. ActiveX Components can be driven by a scripting language such as VBScript or JScript.

ActiveX scripting
n. The act of using a scripting language to drive ActiveX components. ActiveX Scripting is made possible by plugging a scripting engine into a host application. A scripting engine enables the processing of a specific scripting language such as VBScript or JScript. Examples of host applications that contain scripting engines are Microsoft Internet Explorer and Internet Information Server with Active Server Pages. See also script.

ADPCM (Adaptive Differential Pulse Code Modulation)
n. An audio compression scheme that encodes the predicted value of a signal instead of the absolute value of an original waveform so that the compression efficiency is improved. Compare PCM.

ADC (analog-to-digital recorder)
n. A device that converts conventional analog audio and video signals into digital form. It expresses changes in voltage, pressure, or motion over time with a stream of digits that defines an event with time-based data. See also digitize, capture.

AEP (Microsoft NetShow T.A.G. Author Project)
n. An .aep file contains information about the images, audio, and objects that make up an .asf file. An .aep file is created by the Microsoft NetShow T.A.G. Author and is designed for storage of information, not transmission. It is useful for modifying an .asf file because .asf files cannot be edited directly. See also Microsoft NetShow T.A.G. Author, ASF.

AIF (Audio Interchange File)
n. An audio file format developed by Apple computer to store high-quality sampled sound and musical instrument information. The .aif files are a popular format for transferring between the Macintosh and the PC. Compare AU and WAV.

n. A computational procedure for solving a problem. A formula that defines a process or sequence of steps for a computer or intelligent device to perform a task, such as voice compression. Algorithms are the basis of codec compression schemes.

amplitude illustration amplitude
n. The volume of sound as represented by the distance between the highest and lowest points of a waveform. The greater the distance, the louder the sound level or amplitude. Compare frequency.

adj. An analog signal is a constant electrical flow that varies constantly in voltage, unlike a digital signal, which varies between two constant values, usually denoted as 0 and 1. Compare digital.

analog recording
n. 1. The process of recording audio signals by encoding frequency and amplitude variations onto magnetic tape. The alignment of the particles on the tape creates a varying signal during playback, which recreates the original sound.
2. Also, the media that results from this recording process. Compare digital recording.

n. A software program designed to perform a specific task or group of tasks, such as word processing, communications, or database management. Microsoft Word and WordPerfect are word-processing applications; Microsoft Excel and Quattro Pro are spreadsheet applications; Netscape Navigator and Internet Explorer are Internet client applications. Compare program, script.

n. An unintended, unwanted distortion or visual aberration in a digitized video, image, or audio file, often introduced as a result of inaccurate information encoded during capture or compression.

ASF (Advanced Streaming Format)
n. A low-overhead storage and transmission file format that encapsulates multimedia data types (images, audio, and video) as well as embedded text (URLs, for example), and allows for the synchronization of these objects within a stream. NetShow Server stores and streams .asf files.

Microsoft NetShow T.A.G. Author
n. NetShow's graphical content creation tool that allows users to author, test, and generate an .asf file. The tool is designed to handle most of the issues of encoding and synchronization of low to mid bit-rate content. It allows the author to place objects, sounds, images, and URLs so that they appear at the correct time during playback.

ASX (Advanced Streaming Redirector)
n. A simple text file that acts as a link from a Web page to an ASF on NetShow Server or an HTTP server. It transfers control of the data from the HTTP browser to the Microsoft Media Player application so that the data can stream. The ASX text file must specify:
  • The protocol (either HTTP or MMS)
  • The name of the server
  • A virtual directory (if necessary)
  • The .asf file

n. Interchangeable audio file formats used on the Sun Sparcstation, Next and Silicon Graphics (SGI) computers. Essentially a raw audio data format preceded by an identifying header. The .au file format is cross-platform compatible. Compare AIF and WAV.

n. Relating to or capable of producing sound, as in audio tape, audio track, or audio file. A signal or multimedia type composed solely of sound information. Compare illustrated audio, video.

v. To make or construct a multimedia file or presentation. See also multimedia.

AVI (Audio Video Interleaved)
n. The file format for digital video and audio in Windows. In this file format, blocks of audio data are woven into a stream of video frames. The file format is cross-platform compatible, allowing .avi video files to be played under other operating systems. This file format is compatible with NetShow's VidToASF.

n. In certain interframe video compression schemes, a frame in a video sequence that records the change that has occurred when compared to the i-frame before and after it, hence the name bi-directional or b-frame. See also frame, i-frame, p-frame.

n. The maximum amount of data that can pass through a communications channel—such as a network or modem—in a given second. For a digital channel this is measured in bits per second. See also data rate.

adj. A number system that uses only two digits, 0 and 1. Called a base 2 number system. Place value indicates powers of 2. (In the decimal system, place value indicates powers of 10.) Since computers use bits, which have only two states, binary is a convenient number system for representing computer information at its most basic level.

n. Short for binary digit, the basic unit of computer storage. All computer information is ultimately represented as bits. Computer processing capability is evaluated by the number of bits handled at once. Personal computers utilize 8-, 16-, 32-, or 64-bit microprocessors. Compare byte. See also sample depth, pixel depth, bit rate.

bit depth
n. In reference to images, see pixel depth. In reference to audio, see sample depth.

bit rate
n. The speed of a digital transmission, measured in bits per second. See also data rate.

BMP (Bitmap)
n. The usual file extension for certain high-resolution bitmap graphics files usually found in the Windows environment. An image consisting of an array of pixels that can be displayed on a computer monitor.

bps (bits per second)
n. The speed at which data bits are transmitted over a communications medium, such as a transmission wire or a modem. Common PC modem speeds are 28,800 and 14,400 bps. Often expressed in thousands of bits (kilobits) per second.

n. Client software that enables the user to look at, interact with, and generally "browse" files on the Internet. It retrieves a document from a Web server, interprets the HTML, and displays the document on a computer screen. Using a browser, a person can read hypertext and view graphical images. Popular examples include Microsoft Internet Explorer and Netscape Navigator or Communicator.

v. To collect the first part of a streaming media file before playing. Microsoft Media Player is programmed to create a small backlog of information, called the buffer (n), which allows the media to continue playing even if packets are delayed or lost and resent during transmission. Viewers experience a short delay while the media player buffers. Microsoft Media Player also buffers anytime ASF file playback is stopped and restarted. However, due to other factors such as network traffic, data buffering can occur almost anytime during the playing of an ASF file.
n. In data transmission, a temporary storage location for information being received.

n. A group of 8 bits. Usually the smallest addressable unit of information in a data memory storage unit. A single 8-bit byte can describe 256 different binary numbers or values, which is important in discussions of color palette, pixel depth, and audio sample depth. Usually each byte stores one character.

n. A Microsoft file format for compressing files for delivery, similar to .zip files.

n. In Web-based NetShow presentations, brief text messages which can be programmed to appear on the page with Microsoft Media Player. These can be synchronized with the multimedia content to appear, update, and disappear at chosen times. Implementation requires use of a scripting language. See also script commands, markers, URL flips.

v. To convert an analog video or audio signal to digital format. See also digitize.
adj. Term used to describe any device that digitizes analog signals, as in a capture card.

CCITT (Comite Consultatif Internationale de Telegraphique et Telephonique [International Telephone and Telegraph Consultative Committee])
n. A worldwide standards organization that defines communications protocols. Their recommendations enable global compatibility for voice, data, and video transmission over telecommunications devices. See also IEC, ITU, ISO.

n. The color component of a video signal that includes information about hue and saturation. Compare luminance. See also S-Video.

n. A generalized category in object-oriented programming that describes a group of more specific items called objects. Objects of a given class are identical to each other in form and behavior. Program classes are comparable in concept to how people organize information—one familiar example being the categories animal, vegetable, and mineral, which define elements of the physical world.

class identifier
n. In ActiveX, a unique identification tag (UUID) associated with a class object, used most commonly within the <OBJECT> tag. Also CLSID.

n. 1. A computer that receives; the computer that connects to a server. In a client/server environment, the workstation is usually the client computer.
2. Also, a program or application that facilitates a connection to server computers and manages and presents information retrieved from those sources.

n. A model of computing whereby client applications running on a desktop or personal computer access information on remote servers or host computers. The client portion of the application is typically optimized for user interaction, whereas the server portion provides the centralized, multiuser functionality. The aim is to off-load as much processing as possible to the intelligent desktop, leaving only the shared information and the managing software at the central server.

n. A video file.

n. Distortion that occurs when an audio file exceeds the acceptable amplitude, so that peaks of a waveform are cut off. It can be heard as crackling, clicks, or pops on playback.

n. See class identifier.

n. The textual instructions and content in HTML, scripts, or programs. Also, anything in a computer language, either on paper or in the computer itself.
v. To write instructions in a computer language. See also script (v).

codec (compressor/decompressor)
n. An encoding algorithm used to compress digital video, images, or audio for transmission over the Internet or intranets, and then decompress them on arrival. This process allows for faster data transfer and fewer delays. Codecs can employ either lossy or lossless compression schemes.

command line
n. In operating systems that require keyboard characters for instructions, such as MS-DOS or UNIX, this is the line on the display where the cursor is and where the user is prompted to input keyboard instructions. Also the text of the command itself.

command-line interface
n. An unembellished interface in which people interact with a computer by means of a command line. With knowledge of the appropriate text commands, this interface can be very efficient. Compare GUI. See also interface.

command-line utility
n. An application or program that runs from a command-line interface. WavToASF and VidToASF are command-line utilities.

communications protocol
n. A set of rules or standards designed to enable computers to connect with one another and to exchange information with as few errors as possible. Some communication protocols contain other protocols, such as hardware protocols and file transfer protocols. Examples include HTTP, TCP/IP, and MMS.

n. See ActiveX Component.

component video
n. A video signal format that maintains separate channels for all three color values, both in the recording device and in the storage medium. The result is better picture quality. Compare composite video and S-Video.

composite video
n. A video signal format that combines chrominance, luminance, and all color information in one signal rather than the component parts. Any signal that contains all the information necessary to play the video. Compare component video and S-Video.

v. To reduce an audio, image, or video file to a significantly smaller size without altering the substantive information. This is accomplished by the elimination of redundant or repeated data, often for the purpose of transmission. Also encode. Compare decompress.

n. The process of compressing. The conversion of digital data, typically video and audio, into a more compact form by using complicated algorithms. See also codec.

compression scheme
n. A specific strategy or approach to compressing media files, implemented with a mathematical algorithm and delivered as a codec. See also compress and codec.

n. A visual user-interface element that allows a user to interact with data. In a graphical user interface, an object on the screen that can be manipulated by a user to perform an action. Perhaps the most common controls are buttons that a user can click to select an option, and scroll bars that a user employs to move through a document or position text in a window. See also ActiveX control.

DAT (Digital Audio Tape)
n. A system for recording and playback of digital data using special magnetic tape cassettes. A 4mm DAT tape holds one gigabyte of information. DAT recorders can be used to store digital audio or computer data. DAT audio recorders record sample rates of 44.1 kHz and 48 kHz, 16-bit sample depths, with PCM compression and 2 tracks of audio (stereo).

n. Plural of datum, a piece of information. Generally, information of any type, but especially any information in a computer. See also data rate, bit.

data rate
n. The amount of data or bits of information transmitted or moved in a certain time period, usually expressed as bits or bytes per second. In reference to .asf files, the amount of data that must transmit in a given second for the whole file to be heard. For a file to transmit completely and smoothly, its data rate must be less than the bandwidth of its target network.

n. See decompress.

v. To restore compressed video and audio data from its compact form back to its original form in order to play it. Also decode. Compare compress.

n. The process of decompressing. A technique that restores compressed data to its original uncompressed form.

delta frame
n. In interframe video compression schemes, a frame containing only the data that has changed since the previous frame. Compare key frame.

n. Any identifiable subsystem of a computer or network. Drives, video circuitry, printers, modems, routers, the keyboard, the mouse, and ports are devices.

adj. Anything that is digital uses a set of discrete binary numerical values to represent information or signals, as opposed to a continuously fluctuating flow of current or voltage that is analogous to the information it represents. Digital information may represent text, sound, pictures, animations, or video content. Compare analog. See also digitize.

digital encoding
n. Conversion of each sample of a waveform to a number.

digital recording
n. 1. A method of recording audio signals in which portions of sound waves are converted into discrete binary numbers and stored for later reproduction. Digital recording is often referred to as sampling, where digital samples are taken at periodic intervals determined by the sample rate.
2. Also the file that results from this recording process.

v. To convert analog information, such as an audio signal, into digital. The process of turning an analog signal into digital data that can be processed by a computer. Also capture. See also analog, digital.

n. A form of smart conversion from a higher bit depth to a lower bit depth, used in the conversion of audio and graphic files. In the conversion from 24-bit color to 8-bit color (millions of colors reduced to 256), the process attempts to improve on the perceived quality of on-screen graphics with reduced color palettes by adding patterns of different colored pixels to simulate the original color. The technique is also known as "error diffusion," and is applied to audio bit rate reduction and graphic resolution. See also pixel depth, sample depth.

n. On sampling or compressing, the process of reducing the amount of data in a digital file by selecting only certain pieces of the original content. For example, in a 44 kHz, 16-bit digital audio file, each second of sound is recorded in 44,000 discrete, consecutive samples (sample rate), and each sample is recorded in 65,536 separate bits (sample depth). A downsampled 11 kHz, 8-bit file would record each second of sound in 11,000 samples and each sample in only 256 bits. See also sample, compress.

v. In video, to drop frames, or fail to play or capture every frame in a video sequence, usually because of performance limitations of the system playing or capturing the video.

v. To include scripts or objects in a Web page, but not as part of the visible HTML document. For example, use the <EMBED> tag to place the Microsoft Media Player OCX on a page; use the <SCRIPT> tag to embed a script.

v. See compress.

n. The process of reducing or boosting fixed frequencies. Equalization in an audio system usually consists of tone controls designed to adjust the sound output to compensate for room acoustics.

error correction
n. A technique to restore data integrity in received data that has been corrupted during transmission. Error correction adds unique codes to the digital signal at the source so that errors can be detected and corrected at the receiver. Sometimes termed forward error correction.

n. A popular method of networking computers in a LAN. Ethernet will handle about 10,000,000 bits per second (10 Mbps) and can be used with almost any kind of computer.

n. In programming, any action, often generated by a user or a control, to which a program might respond. Typical events include pressing a keyboard key, choosing a button, using a mouse click, and other mouse actions. Programmers write code to respond to these actions.

n. A high-quality audio codec developed by Fraunhofer Institut Integrierte Schaltungen, commonly referred to as MPEG Layer-3. See also codec.

n. The degree to which an electronic system accurately reproduces the sound or image of its input signal.

n. One-half of an interlaced video frame, consisting of every other scan line, an image covering the entire picture height representing the smallest time interval of an interleaved television signal. In a television system of a 2:1 interlace, two fields lasting 1/60th of a second each, one on odd scan lines and one on even scan lines, will interlace to make up a single video frame lasting 1/30th of a second.

file extension
n. An abbreviation of either three or four characters designating a file's type, appended to the end of the file's name and separated by a period. Examples include, .doc or .txt for a text document, .HTM or .HTML for an HTML document, and .avi or .mov for a digital video. For example: glossary.htm. Common NetShow file extensions are .ASF and .AEP. Typically, file extensions may be either uppercase or lowercase.

n. A security mechanism that provides Internet access from computers inside an organization or on an intranet, while at the same time preventing access to the corporate LAN by outside Internet users. See also proxy server.

n. Words or markers added to a command line or code statement that work to change, specify or put conditions on the command. In VidToASF or WavToASF a flag might be used to include a script command text file into an ASF.

fps (frames per second)
n. The number of video or film images displayed per second. United States movie theaters run film at 24 fps, European at 25 fps. Television is 30 fps in the United States and 25 in Europe. Typically, between 8 and 72 fps will produce the perception of intraframe motion called persistence of vision.

n. A single, complete image in a video or film clip. See also b-frame, i-frame, p-frame, delta frame, key frame.

frame rate
n. The number of frames of video displayed per amount of time, usually expressed in frames per second (fps).

frequency illustration frequency
n. 1. The number of times that an alternating current goes through its complete cycle (wave) in one second of time. The pitch of a sound as represented by the length of waves in a waveform. The shorter the wavelength, the more waves per second (higher frequency), and the higher the pitch. Compare amplitude. See also waveform.
2. In reference to sample frequency, the number of samples per second. See also sample rate.

frequency response
n. The range of audible frequencies that a sound system is capable of reproducing at a uniform sound level, or the distance between the highest and lowest reproducible frequencies. The audible frequency spectrum has a range of 20 Hz to 20,000 Hz.

full motion video
n. Video that plays at 30 fps (NTSC) or 25 fps (PAL).

GIF (Graphics Interchange Format)
n. A computer graphics file format developed by CompuServe for use in compressing graphic images, now commonly used on the Internet. GIF compression is lossless. Images that will gain the most from GIF compression are those which have large areas (especially horizontal areas) with no changes in color. Compare JPEG.

GUI (Graphical User Interface)
n. Often pronounced "goo-ee," it describes the screen display that first greets a user and with which the user interacts during a computer session. Technically, any application, such as Microsoft Windows, that lies on top of other applications and provides a user interface based on graphical icons and an event model with which users can control the operating environment. The Microsoft NetShow T.A.G. Author is a GUI. Compare command-line interface. See also interface.

GUID (Globally Unique Identifier)
n. Identifiers (IDs) assigned to objects.

n. ITU standard for real-time low-bit-rate video encoding. Used as a basis for video conferencing over the Internet.

hot spot
n. An area of the computer screen display that is sensitive to a mouse click or other user input. Hot spots are typically revealed to the user by a cursor change, and when clicked will trigger another action.

HTML (Hypertext Markup Language)
n. A tag-based notation language used to format documents that can then be interpreted and rendered by an Internet browser, usually on the World Wide Web, but also on a local computer or intranet. HTML uses tags to identify the format for a particular piece of information. For an example of HTML, view the source of this document.

HTTP (Hypertext Transfer Protocol)
n. A basic communication protocol for Internet or Web server file input and output (I/O).

n. The four unique hues, or colors, are red, blue, green, and yellow. Hue usually refers to a color's comparison with these unique hues, in other words its relative redness, blueness, greenness, and yellowness. Technically, the dimension of color that is referred to a scale of perceptions ranging from red through yellow, green and blue, and circularly back to red. Compare saturation. See also luminance, chrominance.

n. See link.

n. Text which is encoded with a markup language (usually HTML) to create clickable links to other locations, either within the same document or to a different document located on any other accessible machine. Web pages are composed of hypertext, which can also contain pictures, sounds, or video. See also WWW, HTML, link.

Hz (Hertz).
n. The unit for measuring frequency: one cycle (the period of one wavelength) per second. One kilohertz (kHz) is equal to 1,000 cycles per second. See also frequency, waveform.

n. The key frame or reference video frame used in intraframe compression schemes such as MPEG. The i-frame acts as a point of comparision to p- and b-frames and is not reconstructed from another frame. See also frame, b-frame, p-frame.

IEC (International Electrotechnical Commission)
n. International standards and conformity assessment body for all fields of electrotechnology. Works in conjunction with the International Organization for Standards (ISO) to develop, among other things, Internet transmission standards. See also CCITT, ISO, ITU.

IIS (Microsoft Internet Information Server)
n. Internet server software designed to run on Windows NT Server. IIS includes an FTP, Gopher, and World Wide Web publishing service.

illustrated audio
n. A multimedia type that synchronizes audio with images to create an online slide show that can stream at low bit rates. Compare video, audio.

Indeo video
n. Intel's series of codec technologies for digital video, capable of producing software-only video playback.

n. The point at which a connection is made between two elements so they can work with one another. In computing, different types of interfaces occur on different levels, ranging from highly visible user interfaces to often invisible yet necessary interfaces that connect devices and components. The Web browser you are viewing is an example of an interface. See also command-line interface, GUI.

interframe compression
n. A form of video compression in which the codec compresses the data within one frame relative to others. These relative frames are called delta frames. Compare intraframe compression. See delta frame, key frame.

n. The global network of computers that communicate through a common protocol, TCP/IP.

Internet Explorer
n. A Windows-based Web browser manufactured by Microsoft Corporation.

intraframe compression
n. A form of video compression in which the codec compresses the data within one frame relative only to itself. Key frames are compressed with intraframe compression. Compare interframe compression. See also key frame.

n. Use of Internet standards, technologies, and protocols on an organization's internal network. These networks may or may not be connected to the Internet, and are usually protected by a firewall.

IP (Internet Protocol)
n. The transport layer protocol used as a basis of the Internet. IP enables information to be routed from one network to another in packets and then reassembled when the packets reach their destination. See also TCP/IP.

ISDN (Integrated Services Digital Network)
n. Basically a way to move more data over existing regular phone lines. An emerging technology that is beginning to be offered by most telephone service providers as a faster alternative to modems. ISDN combines voice and digital network services in a single medium, making it possible to offer telephone customers digital data service and voice connection through a single "wire."

ISO (International Organization for Standardization)
n. A worldwide federation of national standards bodies from some 100 countries, one from each country. It develops standards for the field of information technology as part of a joint ISO/IEC technical committee. See also CCITT, IEC, ITU.

ISP (Internet Service Provider)
n. An organization that provides access to the Internet.

ITU (International Telecommunication Union)
n. An international organization within which governments and the private sector coordinate global telecom networks and services. ITU develops standards to facilitate the interconnection of telecommunication systems on a worldwide scale. See also CCITT, IEC, ISO.

n. A relatively easy-to-use cross-platform object-oriented scripting language designed for creating live online applications in combination with Java and HTML. It is intended for use by HTML authors for dynamically scripting behavior of objects both on the server and the client. For example, a JavaScript program may be used to create a scrolling marquee on a Web page or to perform some calculation automatically with the click of a button. See also JScript.

n. A widely accepted international standard for compression of color image files, widely used on the Internet. JPEGs can be compressed using lossy compression to decrease file size by as much as 100:1. Commonly applied to photographs, JPEG compression works best with images that do not have large areas of one color. In fact, JPEG compression can introduce artifacts into large areas of one color. Compare GIF.

n. The Microsoft open implementation of JavaScript. JScript is fully compatible with JavaScript in Netscape Navigator version 2.0.

n. Kilo-. Informally, 1,000. Technically, 1,024, so 64 K is actually 65,536. Uppercase "K" is often used for kilobyte, lowercase "k" for kilobit.

KB (kilobyte)
n. 1,024 bytes. Approximately equivalent to half a sheet of paper's worth of typing, double spaced.

Kb (kilobit)
n. 1,024 bits. Also kb.

Kbps (kilobits per second)
n. The common measurement of Internet bandwidth and data transmission rates. Refers to transmission speed of 1,024 bits per second.

key frame
n. In interframe video compression schemes, a frame containing all the data representing an image, rather than just the data that has changed since the last frame. The first frame of every video file is a key frame; in addition, they occur throughout the file to refresh image quality and permit certain operations, such as random user access. Compare delta frame.

kHz (kilohertz)
n. In digital audio, the common measurement of sample rates. One Hertz equals a single sample; a kilohertz equals one thousand samples (not 1,024). A CD-quality sound file is 44 kHz, or contains 44,000 separate samples per second of audio.

LAN (Local Area Network)
n. A group of connected computers, usually located in close proximity (such as the same building or floor of a building) and connected by a communications link that enables any device to interact with any other on the network. Computers connected to a LAN can generally share applications or files from a local file server and may be able to connect to other LANs or to the Internet using routers.

n. A way of jumping from one hypertext document to another. Links generally appear as a highlighted word or image on the screen. Users initiate the jump by clicking the link. Links are the primary way to navigate between Web pages and among Web sites. Also Hypertext Link and Hyperlink.

lossless compression
n. A compression scheme that retains all the original data so that after compression there is no difference between the compressed and decompressed information. See also compress. Compare lossy compression.

lossy compression
n. A compression scheme that removes or alters some of the original data such that it cannot be recovered after decompression. Such compression is still useful because the human eye (or ear) is more sensitive to some kinds of information than others, and therefore does not necessarily notice the difference between the original and the decompressed image or sound. See also compress. Compare lossless compression.

n. The component of a video signal that includes information about its brightness. Compare chrominance. See also component video, S-Video.

n. In NetShow, time points in an ASF to which viewers can "fast-forward." See also script commands, captions, URL flips.

Mbps (Megabits per second)
n. Equivalent to one million bits per second.

n. In object-oriented programming, member functions of an object that perform some action on that object, such as saving it to disk. To invoke a method, an object sends a message consisting of the receiving object and the name of the specific method to invoke. Methods are the mechanism through which objects interact.

MIME (Multipurpose Internet Mail Extension)
n. A protocol standard for e-mail and Web documents that allows the transfer of multimedia. Originally designed as a means of encoding files in Internet e-mail, MIME has evolved into a generic method for indicating the type of a file in newsgroup postings, e-mail, and the World Wide Web.

Microsoft Media Player
n. An ActiveX-based client player application that works with Internet browser software to allow playback of .asf files. Designed to support the streaming of multimedia files from NetShow Server, this client can run as a stand-alone client executable, or it can be embedded in Web pages or Visual Basic applications

MMS (Microsoft Media Server)
n. A protocol used to reference and stream .asf files from Microsoft NetShow Server. Compare HTTP.

modem (modulator, demodulator)
n. A device that you connect to your computer and to a phone line to allow communication with other computers through the phone system. Modems convert the computer's digital signals into analog waves that can be transmitted over standard voice telephone lines. Modem speeds are measured in bits per second (bps), also sometimes expressed as kilobits (thousands of bits) per second.

mono (monophonic sound)
n. A single channel (or source) of audio or sound information. Compare stereo.

n. The file extension used by MOV format video files on Windows. These .mov files are generated with QuickTime, Apple's multimedia environment for the Macintosh operating system, and played on Windows systems via QuickTime for Windows.

n. A codec standard for compressing and decompressing video and audio that allows for better than VHS-quality video and near CD-quality audio by utilizing advanced compression techniques. MPEG employs simultaneous intraframe and interframe compression.

n. A Microsoft Corporation implementation of the MPEG-4 video compression standard used primarily for low-to-medium bit-rate, high-quality video delivery. See also codec, MPEG.

MPEG Layer-3
n. See FHG.

n. Generic description of information that combines some or all of text, still images, audio, animation, and video.

NetShow Server
n. A component of Microsoft NetShow that runs as a Windows NT Server service and is designed for storage and real-time delivery of .asf files. NetShow Server streams .asf files at varied bit rates to Windows 95 and Windows NT clients, and is intended for use on an intranet or the Internet.

n. Any two or more computers connected together so that they can share resources. Connect two or more networks together and you have an internet (small "i"). See also Internet.

network traffic
n. The amount of data being transmitted across a network at a given time. Heavy network traffic is often responsible for packet loss and slow Internet transmission speeds.

n. Any unwanted and unmodulated energy that is always present to some extent within any signal.

noise reduction
n. A technique for increasing the signal-to-noise ratio of recordings. See also noise, signal.

n. A color television transmission standard format with 525 scan lines (rows) of resolution at 30 fps. Established by the National Television Standards Committee, this format is used primarily in the United States, Canada, Japan, and parts of the Caribbean and Central and South America. Compare PAL and SECAM.

n. In object-oriented programming, a variable comprising both routines and data that is treated as a discrete entity. An object is based on a specific model, where a client using an object's services gains access to the object's data through an interface consisting of a set of methods or related functions. The client can then call these methods to perform desired operations.

object-oriented programming (OOP)
n. A method of programming intended to make the writing of complex computer software much easier by simply combining objects together as building blocks to produce a fully functional software application. Programming that allow pieces of software—objects—to be reused and interchanged between programs. Objects contain data as well as instructions that work upon that data. Object-oriented methodology differs from conventional software programming, in which functions contained in code are found within an application.

n. Common reference to an ActiveX control or ActiveX component, so named for their file extensions (.ocx), which originally stood for Ole Custom Controls.

operating system (OS)
n. Software that allows the user and whatever application programs are installed to communicate with the computer hardware. Operating systems include Novell NetWare, XENIX, OS/2, Windows 95, and Windows NT. See also platform.

P, Q 
n. In interframe video compression schemes, a video frame that exhibits the change that has occurred when compared to the i-frame before it, hence the name predictive, or p-frame. The predicted frame which is constructed from preceding reference frames and is used to reconstruct b-frames. See also frame, i-frame, b-frame.

PAL (Phase Alteration Line)
n. A color television transmission standard format with 625 scan lines (rows) of resolution at 25 fps. Established by the National Television Standards Committee, this format is used in most of Europe, Australia, parts of Central and South America, and other countries. Compare NTSC, SECAM.

n. A chunk of information sent over a network, typically a smaller subset of a complete file. Files are broken into packets for ease of transmission. Each packet contains binary information representing both data and a header containing an ID number, source and destination address, and error-correction information. See also IP, packet-switching.

packet loss
n. The delay or disappearance of packets of data, causing them to not reach their destination in a timely fashion, potentially creating an interruption of streamed media. Packet loss is a common occurrence on the Internet, particularly during periods of heavy network traffic. Many transmission applications, including NetShow Server, employ error correction to combat packet loss.

packet switching
n. Data transmission method that divides messages into standard-sized packets for greater efficiency of routing and transport through a network. In this method, all the data coming out of a machine is broken up into chunks, and each chunk has the address of where it came from and where it is going. This enables chunks of data from many different sources to commingle on the same lines and be sorted and directed to different routes by routers, allowing multiple, simultaneous users of network transmission lines. See also IP.

n. In 8-bit images or displays, only 256 different can be displayed at any one time. This collection of 256 colors is called the palette. In 8-bit environments, all screen elements must be painted with the colors contained in the palette. The 256 color combination is not fixed—palettes can and do change frequently. But at any one time, only 256 colors can be used to describe all the objects on the screen or image.

v. 1. When filming, to pivot a camera in a horizontal direction (tilt is to pivot in the vertical direction).
2. In audio, to move sounds between the left and right speaker channels.

PCM (Pulse Code Modulation)
n. Pulse code modulation is a method by which sound is digitally recorded and reproduced. Sounds are reproduced by modulating (changing) the playback rate and amplitude of the sampled (stored) digital pulses (waves). This enables the PCM sound to be reproduced with a varying pitch and amplitude. See also ADPCM.

n. The representation of a sound wave's frequency (the number of cycles per second). The higher the pitch, the higher the frequency of sound waves.

n. An abbreviation for picture element. The smallest independently accessible unit of a digital image, represented as a point with a specified hue and saturation level.

pixel depth
n. The number of bits of color information per pixel. On a computer monitor, each pixel may be represented by a variable number of bits that are used to describe the color of the pixel. Pixel depth determines how many different colors are available. This table shows the relationship:

Pixel DepthAvailable Colors
2-bitblack & white
4-bit16 colors
8-bit256 colors
16-bit65,356 colors
24-bit16,700,000+ colors

n. Refers to a specific combination of hardware, operating system, and/or other software, as in, "This program has been tested on both Windows NT and UNIX platforms." See also operating system.

n. A set of instructions written in a computer language that instructs a computer to perform a task. Compare application, code.

n. A mutually determined set of formats and procedures for the exchange of information between computers. The Internet protocol is TCP/IP.

n. In object-oriented programming, a set of characteristics of an object.

proxy server
n. A proxy server acts as a go-between, converting information from Web servers into HTML to be delivered to a client computer. It also provides a way to deliver network services to computers on a secure subnet without those computers needing to have direct access to the World Wide Web. Thus, secure sites can run a proxy server on their firewall computer. See also firewall.

raster graphics
n. Images defined as a set of pixels in a column-and-row format. Also called bit mapped graphics. See also BMP.

n. A format in which data is uncompressed, most commonly associated with video and audio. See also compress.

n. The processing of information that returns a result so rapidly that the interaction appears to be instantaneous. Information sent in real time needs to be processed almost instantaneously and must arrive in the exact order in which it's sent.
adj. Term used to describe information sent in real time or the applications and protocols that do so. Telephone calls and videoconferencing are examples of real-time applications. See also RTP/RTCP, H.263.

n. 1. The number of pixels in a file. When applied to digital video or images, it refers to the three-dimensional measure of the frame or image composition. Expressed as a series of three numbers, such as 320 X 240 X 24, where the first number is the horizontal width in pixels, the second number is the vertical height in pixels, and the third number is the number of bits describing the color of each pixel (pixel depth).
1. The width and height of the video window or computer monitor display, in pixels. Also screen resolution.

n. Red, green, blue. A color model used chiefly for computer displays in which colors are specified according to their red, green, and blue components. Compare YUV.

RTP, RTCP (Real-Time Protocol, Real-Time Control Protocol)
n. A packet format for sending real-time information across the Internet. An Internet Engineering Task Force (IETF) standard.

RLE (Run Length Encoding)
n. Microsoft's video compression scheme for bitmap graphics image files. A run of pixels of the same color are coded as a single value recording the color and the number of pixels in the run.

n. A device that sends messages by the best route, especially over large networks.

n. A video signal format that maintains two separate channels for luminance and chrominance signals. Also called Y/C video. Compare component video, composite video.

v. To convert an analog signal (such as a sound wave) into a digital format. This is accomplished by measuring the value of the analog signal at regular intervals called samples. These values are then encoded to provide a digital representation of the analog signal. See also capture, digitize, sample rate.
n. 1. The smallest piece of an analog signal, small enough that it can be treated as having a single value, which can be recorded as a digital number.
2. Also (though less technically accurate) a single, complete audio file of any length.

sample depth
n. Bits per sample. The number of bits used to record a single sample of audio, usually 8-bit (256 values) or 16-bit (65,536 values). A higher sample depth results in a more accurate representation of the original signal and higher-quality sound. Compare sample rate.

sample rate
n. The number of samples taken of a signal per unit time, usually expressed as samples per second. The higher the sample rate, the more digital sound data that is recorded, resulting in higher-quality sound and a more accurate recording. Typical sample rates are 8 kHz, 11 kHz, 22 kHz, and 44.1 kHz. CD-quality audio is recorded at 44.1 kHz. Also sample frequency. Compare sample depth.

n. The amount of gray (as opposed to hue) in a color, or the intensity of the hue. Compare hue.

n. 1. A computer program that consists of a set of instructions for an application or utility program. This can be one or more functions, or just a code snippet. See JavaScript, JScript, and VBScript.
2. The text of a video or audio narration.
v. To write or develop a program or piece of code using a scripting language.

script commands
n. In NetShow, commands added to an ASF that generate captions, create URL flips, or place markers. These can be either created with the Microsoft NetShow T.A.G. Author or added via a text file in the WavToASF and VidToASF command-line utilities. See also captions, markers, URL flips.

scripting language
n. A computer programming language with limited scope and capabilites, designed to interact with a particular application or technology. Often a simplified subset or offshoot of another language. VBScript, JScript and JavaScript are scripting languages created primarily to interact with HTML Web pages.

n. Software Development Kit.

SECAM (SEquential Couleur A Memoire [sequential colour with memory])
n. Video format used in France, Eastern Europe, and other countries. Compare NTSC, PAL.

n. A computer running administrative software that controls access to all or part of a network and its resources. A computer or software package that provides a specific kind of service to client software running on other computers. The term can refer to a particular piece of software, such as a Web server, or to the machine on which the software is running (as in "Our mail server is down today; that's why e-mail isn't getting out.") A single server machine could have several different server software packages running on it, providing many different servers to clients on the network. Compare client. See also client/server.

n. A transmitted impulse or a fluctuating electronic quantity, such as voltage, current, or electrical-field strength, the fluctuations of which represent coded sound, image, or message information. See also analog, digital.

stereo (stereophonic sound)
n. Two separate channels consisting of left and right audio or sound information. Compare mono.

v. To transmit multimedia files which begin playing upon arrival of the first packets, without needing to wait for all the data to arrive. To send data in such a way as to simulate real-time delivery of multimedia.
n. The flow of streaming multimedia. In NetShow, this stream is a common format (ASF) that can be rendered by Microsoft Media Player. The data output by NetShow Server is a stream.
adj. streamed, streaming Files or multimedia that stream. For example, an ASF is a streaming file containing streamed media.

n. The "markup" part of the Hypertext Markup Language, tags are the HTML code placed in a document at various points, usually surrounding sections of text, to define how the Web browser displays the document. Tags consist of command text inside less-than and greater-than signs; <P> is a paragraph tag, signaling a hard return and blank line on the page. Tag commands can have attributes, or qualifiers, as in this image tag: <IMG SRC="image.gif" ALT="This is an image." WIDTH=220 HEIGHT=180 BORDER=0>. The <HTML> tag at the beginning of a document signals that it is to be read and interpreted as HTML.

n. A leased-line connection capable of carrying data at 1.544 Mbps, T-1 is currently the fastest speed commonly used to connect networks to the Internet. At maximum theoretical capacity, a T-1 line could move a megabyte in less than 10 seconds.

n. A leased-line connection capable of carrying data at 44.736 Mbps, T-3 is currently the fastest possible Internet connection. Equivalent in bandwidth to 28 T1s. T3 is sometimes called a 45-meg circuit.

talking head
n. Slang term for the video image and sound of a single person talking directly into the camera, such as a head-and-shoulders shot of a newscaster. This type of image is fairly easy to capture with compressed video because there is very little motion.

TCP/IP (Transmission Control Protocol/Internet Protocol)
n. TCP/IP is a combined set of protocols that perform the transfer of data between two computers. TCP monitors and ensures correct transfer of data. IP receives the data from TCP, breaks it up into packets, and sends it to a network within the Internet. Every computer on the Internet supports TCP/IP.

UDP (User Datagram Protocol)
n. A connectionless Internet transport protocol. This means that, as opposed to the more common TCP/IP, an application may send a block of information without any prior agreement from the destination system.

URL (Uniform Resource Locator)
n. An address that uniquely identifies a World Wide Web site. URLs are used to specify the target of a link. A URL can contain more detail, such as the name of a page of hypertext, usually identified by a suffix of .html or .htm.
  • A protocol identifier, such as http
  • The host name, such as
  • The directory and/or file name
  • For example, the following URL is the address of Microsoft NetShow's Web page.

    URL flips
    n. In Web-based NetShow presentations, the synchronized calling up of Web pages at specific time spots within the delivery of the ASF. These calls can be set up to "flip" through a series of HTML documents. The pages can either appear in independent Web browserbrowserndow within a framed Web page presentation. See also script commands, frame (2).

    VBScript (Visual Basic Scripting Edition)
    n. A scripting language that allows for the creation of client applications that are automatically downloaded with the content of a Web page when it is accessed. The applications, called scripts, may then execute on the client machine as traditional programs do or in reaction to user manipulation. A lightweight version of Visual Basic, VBScript is not object-based, but connects and activates objects within HTML documents. See also script, JavaScript, JScript.

    n. A type of multimedia consisting of consecutive displayed images (frames), usually synchronized to an audio track and typically presented at 25-30 fps. To reduce data rates, streaming video frame rates are often reduced to 8-15 fps; this is still considered video.

    Video for Windows
    n. A software-decodable digital video compression scheme developed for Windows operating systems.

    n. A command-line utility that allows you to quickly convert an edited .avi file or .mov file to an .asf file so that it can be stored on NetShow Server and streamed to clients running Microsoft Media Player. Compare Microsoft NetShow T.A.G. Author, WavToASF.

    virtual directory
    n. One or more directories outside the home directory which appear to browsers as immediate subdirectories of the home directory. The virtual directory saves the trouble of typing the entire path to a file. Virtual directories also make it easier to logically organize files in subdirectories. Virtual directories are commonly used for the various services that come with Windows NT Server and IIS, such as HTTP, FTP, and Gopher.

    Visual Basic
    n. A version of BASIC from Microsoft specialized for developing Windows applications. User interfaces are developed by dragging objects from the Visual Basic Toolbox onto the application form. Visual Basic has become a very popular Windows programming language and is often used to write client front ends for client/server applications.

    WAV (Wave)
    n. The Windows-compatible audio file format. The .wav file can be recorded at 11 kHz, 22 kHz, and 44 kHz, and in 8 or 16-bit mono and stereo. Compare AIF, AU.

    waveform illustration waveform
    n. The mathematical representation of a periodic signal, usually a graph of the signal's deviation from a fixed point through time. This fluctuation from the fixed point is in a wave pattern. See also amplitude, frequency, signal.

    n. NetShow's command-line utility that allows users to quickly convert an edited .wav audio file to an .asf file so that it can be stored on NetShow Server and streamed to clients running Microsoft Media Player. Compare Microsoft NetShow T.A.G. Author, VidToASF.

    n. See WWW.

    Web page
    n. A World Wide Web document. These hypertext pages can contain text, images, video, and audio.

    Web server
    n. A computer equipped with the server software to respond to Web client requests, such as requests from a Web browser. A Web server uses the Internet HTTP, FTP, and Gopher protocols to communicate with clients on a TCP/IP network. See also server, WWW.

    Web site
    n. A cohesive collection of Web pages containing links to one another, usually having a uniform design and under the ownership and maintenance of an individual or organization. See also WWW.

    Windows NT Server
    n. A specialized version of the Windows NT (Windows New Technology) operating system, designed to run a server on a LAN. Windows NT is a self-contained operating system which does not use MS-DOS. It runs Windows NT-specific applications as well as MS-DOS and Windows applications.

    WWW (World Wide Web)
    n. A set of services that run on top of the Internet providing a cost-effective way of publishing information, supporting collaboration and workflow, and delivering business applications to any connected user in the world. The Web is a collection of Internet host systems that make these services available on the Internet using the HTTP protocol. Web-based information is usually delivered in the form of hypertext and hypermedia using HTML. The most graphical service on the Internet, the Web also has the most sophisticated linking abilities. Also the Web.

    X, Y, Z 
    n. A color model used chiefly for video signals in which colors are specified according to their luminance—the Y component—and their hue and saturation—the U and V components. Compare RGB. See also chrominance, luminance, hue, saturation.