Video Dictionary


A B C D E F G H I J K L M N O P Q R S T U V W Y Z



8-bit video

Video file that uses up to 256 colors to display the colors in each frame.



Alpha blending

Creating transparent materials with the help of additional information for each pixel.



Analog

Continuously varying electronic signal to reproduce information. Compare digital.



Analog Display

Monitor that uses variable color control voltages to display a very large number of colors but requires very few inputs.



ANSI

American National Standards Institute.



Anti-aliasing

Interpolating the colors of neighboring pixels in order to avoid the 'pixel look' of an image.



Artifacts

Blurred or "blocky" portions of degraded image quality in a digital video.



ASCII

American Standards Committee on Information Interchange. A standard used by IBM and compatible computers to represent numbers and characters in binary form.



Aspect ratio

Proportions of a TV or film picture, generally given as the ratio of the width to height. The standard TV picture has an aspect ratio of 4x3, or 4:3. High-definition video systems may have aspect ratios of 6x8 or greater.



Authoring Systems

Authoring systems are used to create multimedia applications. They combine existing presentation information (texts, images and sound) and control the flow of these during the multimedia show. The dialog with the user is controlled with this software. The individual information must have already been created and saved with special programs.



AUTOEXEC.BAT

Batch file that directs the activities performed by the computer during system startup.



AV Hard disks

Hard disks with a special audio / video firmware which ensures a constant data flow. Recalibrations that could interrupt the data flow are suppressed and an internal recording format is used on the hard disk.



AVI

Audio Video Interleaved. AVI files are the standard format for digital video films on PCs.



B Frame

MPEG video frame type that provides bi-directional interframe compression. B frames derive their content from the closest I or P frames, one in the past and one in the future. B frames require greater computing power to produce than I or P frames. B frames enable compression rates of 200:1. Robust MPEG encoders employ a combination of B, I and P frame encoding.



Bandwidth

Required capacity for the data volume and transmission rate.



Bi-directional prediction

Form of compression in which the codec uses information not only from frames that have already been decompressed, but also from frames yet to come. The codec looks in two directions: ahead as well as back. This helps to avoid large spikes in data rate caused by scene changes or fast movement, improving image quality. Compare unidirectional prediction.



BIOS

Stands for Basic Input-Output System. Code in your computer's ROM (Read Only Memory) that provides the power-on self test and other operating functions.



Bits per pixel

Number of bits used to represent the color information of a pixel.



Blitter

Fast memory transfer in the graphics board without using the CPU, e.g. used for moving parts of the invisible screen.



BMP (Windows Bitmap)

This format enables Microsoft Windows to display images on devices with similar capabilities in a consistent way. Save pictures in this format if you wish to continue to process them later under Windows.



BNC connector

Standardized connector with a bayonet socket, used for connecting a graphics board to a monitor with separate R(ed), G(reen) and B(lue) inputs.



Booting/Booting Up

Starting the computer. There are two types. Warm booting is accomplished by simultaneously pressing the CTRL/ALT/DEL keys and can occur only when the computer is running. A cold boot requires activation of the ON/OFF switch.



Brightness

Brightness of an image is determined by the amount of light emitted by it. No light (black) therefore means 'no brightness', whereas pure white light means 'maximum brightness'.



Burst mode

Fastest data transfer mode in which a large burst of pure data is transferred in one block.



Bus master

PCI bus slots must have bus master capability. This means PCI extension boards may move data very fast via the PCI bus without using the CPU (similar to Direct Memory Access).



Bus system

System of parallel data lines to transfer information between individual system components, especially to expansion boards (e.g. PCI bus).



Camcorder

One-piece video camera and recorder combination.



Capture

Process of converting a video or audio signal from a television, VCR, tape deck, or other source into a digital file that you can manipulate on a computer.



CD-I

Compact Disc Interactive. A technique developed by Philips in order to playback games, films and music videos on a CDI player.



CD-ROM

High-density medium to store digital data. CD-ROMs have read-only status. There are different CD-ROM formats:
YellowBook: conventional CD-ROM format
GreenBook: used for linear video, this is typical for CD-Is (see below)
WhiteBook: used for Digital Video VideoCDs.



CGA

IBM Color Graphics Adapter.



Chroma key

Technique allowing video technicians to place foreground objects over synthesized backgrounds, such as a TV meteorologist who appears to be standing in front of a map, when in fact he or she is merely standing in front of a blue wall. Chroma key circuitry electronically separates the foreground pixels representing the meteorologist from the blue background pixels and overlays the meteorologist on top of an electronically generated weather map. Compare transparency.



Chrominance

Portion of a video signal which corresponds to color values and includes information about hue and saturation. This color component essentially complements the brightness or luminance component of a color video picture.



CIF

Common interchange format; interchange format for video images with 288 lines with 352 pixels per line of luminance and 144 lines with 176 pixel per line of chrominance information.



Cinepak

Software-Codec. Makes fast decoding possible. Good image quality possible as long as the image dimensions are not increased. The video encoding process is time-consuming.



Clip

File containing a short video sequence.



Clipping

Limiting the drawing area to any rectangular area by cutting its edges.



CODEC

Compressor / Decompressor, responsible for the compression and decompression of image data.



Color Display

Type of monitor capable of displaying information in color. It is often called an RGB (red, green, blue) monitor, referring to the signals needed to drive it.



Color Palette Conversion

Conversion of video data from the YUV color model into the RGB color model, or v.v.



Component video

Video signal format that separates chrominance and luminance into two waveforms. Compare composite video.



Composite video

Video signal format that includes all the visual information in one waveform, including chrominance, luminance, blanking pedestal, field, line, color sync pulses and field equalizing pulses. Compare component video.



Compression

Process of removing redundant data from video, sound and graphic files to reduce file size and enhance playback.



CONFIG.SYS

ASCII file that is created to provide the computer with special information about applications and hardware.



Contrast

The contrast of an image is the difference between light and dark. A contrast-intensive image is one in which contains strong transitions from light to dark. A contrast-weak image contains transitions that are hardly noticeable.



Data Transfer Rate

The data transfer rate describes the amount of data transferred to or from the storage medium (e.g. hard disk) per second. Each data storage medium has a specific data transfer rate which it can handle. Typical values are:
- old hard disks 300 KB/s
- new hard disks 600 KB/s
- standard CD-ROM drives 150 KB/s
- DoubleSpeed CD-ROM drives 300 KB/s



DCI

Display Control Interface. An interface defined by the Intel and Microsoft corporations, which enables enhanced graphics performance due to direct access to the video memory.



DCT

Acronym for Discrete Cosine Transform. A method of compressing individual images which is the main part of JPEG and I-frame MPEG compression.



Decode

Process of decompressing a video clip and then converting its color space from YUV to RGB. Compare encode.



Decompression

Process of a computer reading a compressed file so that the information in it can be displayed or played back.



Default Mode

Capabilities, resolutions and display mode the system operates with when you start your computer.



Defragment

To reorganize noncontiguous clusters of information on your hard disk into contiguous files to improve performance.



Delta frame

Frame containing only the data that has actually changed since the last frame. Delta frames are an efficient means of compressing image data. Compare key frame.



Digital

(1) Method of representing sound or other waves as a series of binary numbers. (2) Tuning method for radios in which the desired freq. is set by digital calculation. (3) Numeric display of information. Compare analog.



Digital Display

Also called TTL. A type of monitor that switches signals ON or OFF to determine display color. Types of digital displays include the IBM Enhanced Color Display or Monochrome Display.



Digital Video

Digital videos contain optical information bitwise in a file.



Digitize

Process of turning an analog signal into digital data.



Digitizer

Input device in the CAD area, used for scanning printed graphics or drawings, i.e. converting them to digital computer graphics.



DIP Switch

Dual Inline Package switch; a series of tiny, two position switches which allow users to select and change options on computer boards, printers, and other peripherals.



Dither

Process of representing a color by mixing dots of closely related colors.



Double buffering

Also called page flipping. The display buffer has double size. The next image can be drawn in the part of the display buffer which is invisible at first. When it is ready, this part will be displayed, and in the other part the next image will be prepared. With this technique animation and games look more realistic than with a simple single buffer.



Driver

Part of a software program that interacts with a particular piece of equipment in your computer system (i.e. video boards, printers, and keyboards). Drivers are often loaded by your config.sys at system boot.



Dropped Frames

Images of a video which are not displayed or recorded when replaying (resp. recording).



Dubbing

( 1) Process of copying a recording to make a duplicate. (2) In motion-picture sound, replacing a foreign language soundtrack with dialogue in the language of the audience.



DVD

Acronym for Digital Versatile Disk - optical disks that contain full-length motion pictures for viewing on a personal computer. These disks are the same size as a standard CD-ROM, but have a capacity of up to 17 GB.



EEPROM

Electrically Eraseable Programmable Read Only Memory; used to replace DIP switches and jumpers on new graphics boards like yours.



EGA

IBM Enhanced Graphics Adapter.



EMS

Enhanced Memory Specification. Originally developed to break the DOS 640K limit, it is now used as a general term for types of add-in memory.



Encode

Process of converting the color space of a video clip from RGB to YUV and then compressing it. Compare decode.



Enhanced Color Display (ECD)

IBM Enhanced Color Display capable of 640 x 350 resolution.



EPS (Encapsulated PostScript)

EPS is a device-independent file format, which contains all the information required to reproduce an image directly on a PostScript printer or to use it in suitable applications. A small header section contains the data of the image as a TIFF-format file so that applications that can not display PostScript data directly can still obtain an impression of the file contents.



Expansion Board

Device used to expand a computer's capability.



Expansion Slot

Electrical connection within the computer used for the addition of Expansion Boards.



FCIF

Full CIF. Number of lines and pixels used to form an image on the monitor. Full CIF creates a better image than QCIF (partial CIF).



Feature connector

Also called VGA output connector. 26-pin connector for connecting expansion boards to a graphics board using a flat cable.



Field

One half of a video frame, consisting of every other row (scan line). See interlacing.



Fill-in Images


When video data is being saved onto a CD-ROM (during manufacturing) the images are normally 'polstered' with fill-in images so that each video file completely uses the assigned 2KB area. This ensures a constant data rate and a smoother playback appearance. The file size is not changed by doing this.



Filter

Special effect applied to a video clip or image to alter its appearance. Filters can also correct problems involving color balance or brightness and contrast.



First-frame analysis

Transparency technique wherein the first frame of the video file is a dummy frame that supplies the color or range of colors to be rendered as transparent: e.g. the color of the chroma-key background.



Fixed Frequency Monitor

Analog monitor which can only sync to a very narrow range of scan frequencies.



Fog

Fading effect that depends on an object's distance from the viewer.



fps

Frames per second. Measurement unit for the frame rate.



Frame

Single video image.



Frame Rate

Number of images shown per time unit. Software videos have a fixed frame rate. When playing back the actual frame rate achieved can differ to the rate defined in the video considerably.



Framegrabber

If an overlay board (see below) also contains a real-time video digitizer (= frame grabber), then the user can capture a random frame from the video sequence being replayed and can save this onto his hard disk.



Frame size

Width and height of a frame expressed in pixels.



Frequency

Number of samples per second in a sound or video file. The higher the frequency, the better the quality of the sound or video.



Full motion video

Video that plays at 30 frames per second (NTSC) or 25 frames per second (PAL).



General MIDI

The MIDI Association's MIDI Song File standard has established itself as the General MIDI standard for the exchange of MIDI music data between different PC systems.



GIF (Graphics Interchange Format)

Graphics file format developed by CompuServe to enable the device-independent exchange of images between systems. GIF-format files can be up to 64MB in size with color information up to 256 colors (8 bits). GIF files do not contain information about the image resolution.



Graphics accelerator

Device the purpose of which is to increase speed in performance-demanding graphical environments.



Grayscales

Grayscale image consists of different shades of gray (like a black-and-white photograph). This normally means that 254 different grayscales plus black and white (= 256) are used.



H.261

Video compression/decompression technique similar to MPEG I and P frames but best-suited for video with little motion.



Hardware Cursor

The cursor's movements and display are controlled by the accelerator chip. This means that the CPU only has to pass the mouse co-ordinates to the graphics board, reducing the CPU's workload.



Hardware Encoders

Specialized, high-performance processor used for compressing. Performance is generally faster than that of software encoders because a processor is dedicated to encoding video. Hardware processors may be included on a computer's motherboard or on an add-in board. General operation of the computer is controlled by the main processor, the performance of which is largely unaffected by the encoder's operation.



Hercules Graphics Card (HGC)

Video adapter that provides bit mapped single color graphics.



Hexadecimal Notation

A base-16 numbering system that uses numbers and letters. The hexadecimal sequence begins: 1 2 3 4 5 6 7 8 9 A B C D E F, then 10, 11 etc.



Horizontal Frequency

Rate at which a monitor displays each scan line. Usually measured in kilohertz (kHz).



Hue

Synonym for color.



I Frame

MPEG video frame incorporating intraframe compression where only the information in a single frame is considered. Unlike P and B frames, I frames do not take redundancy between adjacent frames into account. I Frame encoding compresses at up to a 6:1 ratio before noticeable artifacts appear. It is used in conjunction with B and P frame encoding.



I/O Port

Input/Output port. An address used to access a hardware device.



Image Compression

Technique used to reduce the volume of data in digital image and video files.



INDEO

Intel Video. Compression technique developed by Intel. Gives good quality but requires a high level of processing work to decompress.



Indexed 16 and 256 Color Images

Indexed color images contain a color table in the file. This table lists all the colors that could be used in the file. An indexed 16-colour image contains a table with 16 color entries (4 bits) whereas an indexed 256 color image 256 colors are listed (8 bits).
Other colors can be simulated in a way similar to using grayscales in a black-and-white image, by simply positioning the pixels in varying densities. The eye then sees color mixtures that are not actually in the color table.
You can transform images into indexed color images in order to load them into programs such as Windows Paintbrush, or just to see them on monitors that can only display 256 or 16 colors.



Interlaced Display

Monitor that refreshes every other scan line every other pass of the screen. A non- interlaced monitor refreshes the entire screen (every scan line) every pass of the screen.



Interleave

Technique used to organize audio and video data so that every audio data segment is followed by video data, e.g. AVAVAV.....



Interpolation

Video image must be stretched or shrunk in order to fit into the display window. If pixels are simply multiplied (e.g. a block of four equally colored pixels represent the original pixel), aliasing effects ('blocks' and 'stairs') will occur. This can be avoided by interpolation procedures (using average colors for inserted pixels). Horizontal interpolation is relatively easy to perform, since the pixels are drawn to the screen in lines. Vertical interpolation is more difficult and requires a complete pixel line to be buffered.



Interrupt Request (IRQ)

Signal used by a device, such as a mouse, to inform the CPU that it is present and functioning.



Intraframe compression

Form of compression in which the codec compresses the data within one frame relative only to itself. Key frames are compressed with intraframe compression because they must reconstruct an entire image without reference to other frames.



ISDN

Integrated Services Digital Network; refers to an end-to-end circuit switched digital network intended to replace the current telephone network. ISDN offers circuit-switched bandwidth in multiples of 64 kb/s (B or bearer channel), plus a 16 kb/s packet-switched data (D) channel.



JPEG

New compressed file format industry standard developed by the Joint Photographic Experts Group. It enables compression ratios up to 100:1 (original file size to compressed file size). A new feature of this standard is that it is device-independent. These files can be replayed using any application that supports this format. JPEG differs from the LZW compression method in that it works with quality loss. This means that some of the original data is lost during the compression phase. In order to surpass this visual effect JPEG compression attempts to 'lose' information which is less important to the human eye. Use this format if you don't have much memory space available or if you are processing very large image files.



Jumper

Small plastic plug that fits over a pair of pins. When the plug straddles two pins it makes an electrical connection. The computer makes decisions based on whether the connection is made or not. A group of jumper pins is called a jumper block.



Kbps

Kilobits per second, a quantity for measuring transmission speeds.



Keyframe

Technique used to compress video data whereby certain frames are defined as 'keyframes' and are fully saved during compression. The video data of the frames between two keyframes are only partially stored. During decompression the 'partial frames' use the information stored in the keyframes.



Line Drawing

This is a hardware function of the graphics processor chip. Only the starting and ending co-ordinates of a line are supplied by the CPU. The rest of the work drawing the line is then done by the graphics processor.



Lossless

Describes a compression method that preserves all the data in the video or image being compressed. Lossless compression routines, such as MicroSoft RLE, maintain image quality but do not reduce file size as much as lossy routines.



Lossy

Described a compression method that eliminates data from the video or image being compressed. Lossy compression routines, such as Cinepak and Intel Indeo, significantly reduce file size but may also affect image quality. However, the result may be imperceptible to your audience.



Luminance

Portion of a video signal corresponding to brightness value - essentially the black-and-white foundation of a color video picture.



MCI (Media Control Interface)

Windows standard interface that enables software to control external media devices such as video decks.



M-JPEG

Motion JPEG. A codec (see above), which is especially suited to video processing. Hardware decompression is strongly recommendable for this.



MDA

IBM Monochrome Display Adapter.



MIDI

Musical Instrument Digital Interface. A serial interface used to link computers, synthesizers and other electronic sound generating devices.



Monochrome Display

Monitor that displays information in one color only; sometimes called a black & white display.



Morphing

Special effect in which one shape is gradually transformed into another.



MPC

Multimedia PC. This trademark is intended to help consumers when purchasing hardware and software (similar to the VHS symbol used in the video product market).



MPEG

Motion Picture Expert Group. The compression method known as MPEG 1 is suited to digital video playback. A hardware decompressor is necessary.



MPEG

MPEG stands for Motion Pictures Experts Group, a group of the ISO committee for standards. With the MPEG format an international standard for the display of 25 images per second and a transmission rate of between 150 and 300 Kbytes per second is defined. Through a highly sophisticated compression method MPEG is a way to display full screen and full motion video with CD sound quality using little memory.
This way, MPEG files can be played back as well as Video CDs, interactive programs and presentations.



MPEG-1

Set of international standards for the compression and decompression of digital video signals. MPEG-1 specifies a video resolution of 352-by-240 pixels compressed at 30 / 25 frames per second (fps) at a bandwidth of 150 kilobytes per second.



MPEG-2

Targeted for use with high-bandwidth broadcast applications specifying 720-by-480 playback at 60 fields-per-second at data ranging from 500 kilobytes per second to more than two megabytes per second. In general MPEG-2 will be used for digital television and with DVD drives.



MPEG-3

Now part of MPEG -4.



MPEG-4

Designed for future use with video conferencing.



MT-32

The MIDI module MT-32 created by Roland.



Multi-frequency Monitor

Type of monitor that supports a wide range of horizontal scanning frequencies and vertical refresh frequencies. This type of monitor accepts inputs from many different video display adapters.



Multimedia

Information that combines some or all of text, still images, sound, animation and video.



NTSC

National Television Standards Committee. The committee responsible for the definition of the North American television standard (with the same name). NTSC creates 30 images per second.



Offline encoder

Indeo video codec's normal mode of operation, in which it takes as long as necessary to encode a video file so that it displays the best image quality and the lowest and most consistent data rate. Compare quick compressor.



Overlay Boards

Overlay boards are able to digitize video images being input in real-time, to synchronize the data with the random segment of the screen and to show both images (incoming video signal and background screen image) simultaneously on the PC's monitor. The result is a window showing a video film which is placed over a background (e.g. a Windows application).



P Frame

MPEG encoding method using a predictive algorithm to take into account information that is common among adjacent frames. P frames predict the difference between the current frame and the closest preceding I or P frame to minimize the amount of data that needs to be coded for each frame. P frame encoding is used in conjunction with I and B frame encoding.



PAL

Phase Alternation Line. PAL is the television standard used in Germany and Great Britain. The video signals are transformed into 25 images per second.



Palette

Selection of colors from which to choose. Your board provides as many as 16.7 million simultaneous colors from a palette of 16.7 million. This capability is sometimes referred to as TrueColor. It is believed that the human eye can discern no more than 16.7 million colors.



Palette flash

Phenomenon caused by simultaneously displaying more than one bitmap or video that do not share the same palette.



PCX (PC Paintbrush)

This file format was developed by Zsoft Corporation for PC Paintbrush, one of the first computer drawing programs. It is the standard format for many scanners and drawing programs. Some versions of the PCX format don't contain any information about the resolution of the image.



Peripheral Equipment

Auxiliary equipment connected to a computer (e.g. monitor, printer, keyboard, etc.).



Pixel

Short for picture element; the smallest field displayed on the monitor; could be compared to the dots which form images in photos printed in newspapers. Also called pel.



Pixel clock

Also called pixel frequency. Number of pixels drawn per second in MHz (million pixels per second). The values are either fixed or freely programmable.



Pixel depth

Also called color depth. Number of bits of color information per pixel. A system using eight bits per pixel can display 256 colors. A system using 16 bits per pixel can display 65,536 colors. A system using 24 bits per pixel can display over 16.7 million colors. Twenty-four­bit color is often called true color because the human eye can distinguish among approximately six million different colors, or fewer than are available in a 24-bit color system. 24 bits means 8 bit for each RGB. With 32 bit pixel depth 8 bits are used in addition for an Alpha Channel.



Polygon Fill

Special hardware (chip) routine used to fill polygons with pixel information.



Primary Display

Monitor which is active when you power on your system.



PS/2 Display Adapter

IBM VGA board for Industry Standard Architecture (AT bus) computers.



QCIF

Quarter CIF (176 x 144 pixels). Quality of the picture on the monitor. QCIF half as many lines and half as many pixels per line as CIF, i.e., luminance information is coded at 144 lines and 176 pixels per line. It creates a "watery" image.



Quick compressor

Compressor compatible with Indeo video interactive that handles data more quickly than the offline compressor. Videos that compress in hours can take minutes using the quick compressor. Compare offline encoder.



QSIF

Quarter size of the Standard Image Format. Resolution of 176-by-140 pixels for NTSC.



RAM

Random Access Memory; memory that can be read from and written to.



Real-Time Capture

Capturing and digitizing video at 30 frames per second.



Refresh rate

Vertical refresh rate in Hz indicates how many full images per second are displayed on the monitor. The higher the refresh rate, the less the display will flicker.



Rendering

Process of displaying an object with shading effects to yield a more natural three-dimensional appearance.



Resolution

Number of pixels (from picture cells) in both horizontal and vertical directions.



Resolution

Number of pixels displayed on the monitor. The higher the resolution, the crisper and sharper the images appear.



RGB 8Color

RGB8 color file types are 3 bit types in which each pixel can have one of 8 colors. The RGB8 color images are automatically transformed into indexed 16 color images whereby the 8 colors are retained but space for further 8 colors is created. It is not possible to transform an existing file into an RGB8 color file type.



RGB Color Model

Monitors use additive mixing of the three basic colors red, green and blue to create images on the screen with an infinite number of colors. Image data is therefore processed via data for RGB color combinations. The combinations of the three basic colors create a color model whose origin is the color black and the opposite value is the color white.



RGB True Color

RGB stands for red - green - blue. All the colors that are used in this file are created additively mixing parts of the three basic colors. The parts of the three basic colors can be varied in 256 steps. If you mix all these colors together a total of 16.7 million possible color combinations is attainable (3x8 bits = 24 bits, 2 to the power of 24 = 16.7 million). As the human eye can not tell the differences between color hues from about this level, such an image is termed 'True Color', i.e. 'as in real life'.



ROM

Read Only Memory; memory space in your computer for storing permanent operating instructions.



Saturation

Amount of gray in a color determining the intensity and purity of a color. A color with a high saturation value is optically very intensive. A color with a low saturation value appears weak (i.e. with less color content).



Scalability

Feature of the Indeo video codec with which quality can be optimized during playback depending on the system resources being used to play the video.



Scaling

Transformation of image data to different sizes.



SECAM

Acronym for Sequentielle Couleur Avec Mémoire. A video standard used in France, Eastern Europe, Russia and parts of Africa. The SECAM standard has a vertical resolution of 625 lines and a frame rate of 25 frames per second.



Shading (flat, Gouraud, Phong)

Shading or rendering is a way to define the colors on curved surfaces in order to give an object a natural appearance. To achieve this, the surfaces are subdivided into many small triangles. The three most important 3-D shading methods differ in the algorithm used to apply to these triangles:

- Flat shading: In this simplest method each triangle gets one single color, resulting in a faceted appearance of the surface.

- Gouraud shading: The color shades on a triangle are calculated by interpolating the vertex colors, resulting in a smooth appearance of the surface.

- Phong shading: The color shades on a triangle are calculated by interpolating the vertex colors, additionally regarding the normal vector at each triangle (i.e. its orientation in space).



SIF

Standard interchange format; format for exchanging video images of 240 lines with 352 pixels each for NTSC, and 288 lines by 352 pixels for PAL and SECAM. At the nominal field rates of 60 and 50 fields/s, the two formats have the same data rate.



Software Encoders

The main processor of a desktop computer uses software to perform compression. Performance is generally below that of hardware encoders because the process is not specialized and power must be divided among encoding, running the computer's basic functions, and other applications.



Sound Files

Most common file type for sound files under Windows are WAV files.



Storyboard

Frame-by frame sketch that maps the key objects and actions in an animation or video. Used in planning the animation or video project.



Sync

Stable condition which exists when two repetitive events maintain a constant time relationship; your monitor is in sync with the signals from your board when the display is correct and stable.



Terminate and Stay Resident (TSR)

Programs that are run once then remain in memory in order to be activated by a sequence of key strokes or a 'hotkey.' It is possible that a TSR may take up too much memory and cause conflicts with other programs.



Texture mapping

Wrapping a bitmap around an object, including perspective correction, for example a wallpaper on a wall or a wood texture on furniture. A video can also be used as texture map.



TGA (Targa)

Developed by the company True Vision especially for its true color video boards (especially the Targa board), this is a format preferred by many specialists.



TIFF (Tagged Image File Format)

This format was developed by Aldus and Microsoft in order to promote the use of desktop scanners and DTP systems. Uncompressed TIFF files are hardware and software-dependent, however there are different incompatible compression methods. Select this format for the maximum compatibility with other applications and to improve the compression level.



Time code

Time value that identifies the position of a clip in a video sequence with respect to a starting point, usually the beginning of the video project (in a digital format) or source tape (in an analog format). Its standard form is Hours:Minutes:Seconds:Frames.



Transparency

Feature of the Indeo video interactive codec in which software emulates chroma keying, allowing foreground video objects to be composed dynamically over a different background, a bitmap, or possibly even another video. See chroma key.



Transparency frame

First frame of a video file in the transparency technique first-frame analysis. It contains no video data, but merely supplies the color or range of colors to be rendered as transparent. See first-frame analysis, transparency.


TrueColor

Ability to display 16.7 million simultaneous colors. It is believed that the human eye can discern no more than 16.7 million colors. See 'palette'.



Unidirectional prediction

Form of compression in which the codec uses information only from frames that have already been decompressed. Compare bidirectional prediction.



Variable Frequency Display (VFD)

Monitor that is capable of displaying a wide range of resolutions through it's ability to sync to a wide range of horizontal and vertical scan frequencies.



Vertical Frequency

Rate at which the monitor screen is refreshed. Usually measured in hertz (Hz).



VGA

IBM Video Graphics Adapter.



VHS

A videocassette format. using 1/2-inch (1.27-cm) tape. VHS-C is a smaller VHS cassette. Super-VHS (S-VHS) incorporates advanced digital circuitry.



Video CD

The VideoCD specification was published in 1993 by JVC, Matsushita, Sony and Philips as the so-called 'Whitebook' standard. Using this up to 74 minutes of digital video compressed with the MPEG 1 technique can be stored on a CD. The image resolution is 352 x 240 pixels and 30 frames per second for the NTSC standard and 532 x 288 pixels at 25 fps for PAL.



Video Connector

Standard 15-pin monitor output connector located on the board.



Video Electronics Standards Association (VESA)

Industry-wide consortium organized to standardize graphic modes. Your board supports the VESA standards.



Video Keying

This term refers to the process of mixing two video and computer graphics signals.



Viewport

Rectangular section of the video image that is displayed using local decode.



VTR

Acronym for Video Tape Recorder, a video recording and playback tape deck, usually of professional quality.



Wavelet

Compression algorithm that samples the video image based on frequency to encode the information. This creates a series of bands representing the data at various levels of visual detail. The image is restored by combining bands sampled at low, medium, and high frequencies.



YUV Color Palette

The image information of individual frames is comprised of a brightness part and 2 color parts. The color part is calculated by evaluating the difference to the brightness value. This method was first utilized in television technology.



YUV Signal

Video signal that is comprised of a brightness part (luminescence Y) and two color parts (chrominance U and V). Due to the characteristics of the human eye, it is enough to transfer the color parts with a lower resolution. This mixture is technically achieved by only evaluating 2 chrominance signals U and V compared with the 4 values calculated for the luminescence. This results in statements in the format 4:2:2. Other constellations are possible.



YUV9

Bitstream format that does not compress the video signal, but converts it from the RGB into the YUV color model and averages pixel colors so that the signal uses only nine bits per pixel.



YUV9C

Bitstream format that converts the video signal from the RGB into the YUV color model, averages pixel colors so that the signal uses only nine bits per pixel, and then compresses the signal slightly.



Z-Buffer

3-D depth information (position in the third dimension) for each pixel.



Zone Bit Recording (ZBR)

Recording procedure where the default amount of bytes per sector is identical, but the amount of sectors varies, depending on the circumference of the hard disk. The bigger the circumference, the more sectors can be found. By this way there are different zones with a different number of sectors on the hard disk (inner track with less sectors, outside track with more sectors). Thus, the capacity of the hard disk is used in the most profitable manner. The result is a higher data rate on the outer tracks than on the inner tracks. In general, the more the hard disk is filled, the slower it becomes.



Zooming

Increased display of an image section.