Video and Multimedia Glossary
3:2 Pulldown:
The technique used to convert 24 frames per second film to 30 frames per second video. Every other film frame is held for 3 video fields resulting in a sequence of 3 fields, 2 fields, 3 fields,2 fields, etc. (See Fields, Frames)
4 fsc:
Composite Digital video as used in D2 and D3 VTRs. Stands for 4 times the Frequency of Subcarrier, which is the sampling rate used.
4:2:2:
The sampling ratio used in the D1 (CCIR 601) digital video signal. For every 4 samples of luminance there are 2 samples each of the color difference signals, R-Y (Red minus Luminance) and B-Y (Blue minus luminance).
4:1:1:
The sampling ratio used in the DV or DVC (Digital Video, Digital Video Tape) digital video signal. For every 4 samples of luminance there is 1 sample each of the color difference signals, R-Y (Red minus Luminance) and B-Y (Blue minus luminance).
4:2:0:
The sampling ratio used in some variations of DV digital video signal. For every 4 samples of luminance there is a sample of one of the color difference signals, followed by a sample of the other color difference signal on the next luminance sample.
4:4:4:
A sampling ratio that has equal amounts of the luminance and both chrominance channels. Can also be used for RGB sampling, the color space used in most computer programs.
160 (16 by 9):
A wide screen television format in which the aspect ratio of the screen is 16 units wide by 9 high as opposed to the 4x3 of normal TV.
10 BaseT:
An Ethernet network implemented on twisted-pair cabling.
A-Frame Edit:
A video edit which starts on the first frame of the 5 video frame (4 film frame) sequence created when 24 frame film is transferred to 30 frame video (see 3:2 pulldown). The A-frame is the only frame in the sequence where a film frame is completely reproduced on one and only one complete video frame. Here is the full sequence. (The letters correspond to film frames.) A-frame = video fields 1 & 2, B-frame = video fields 1 & 2 & 1, C-frame = video fields 2 & 1, D-frame = video fields 2 & 1 & 2.
A-Mode Edit:
An editing method where the footage is assembled in the final scene order. Scene 1, scene 2,...
Activemovie:
Microsoft's architecture for the control and processing of streams of multimedia data and software that uses this architecture to play digital video and sound. It is intended to supersede Video for Windows.
Active Picture Area:
The part of a TV picture that contains actual image information as opposed to sync or other data. Vertically the active picture area is 486 lines for NTSC and 576 lines for PAL. The inactive area is called blanking.
AES/EBU:
The digital audio standard set by the Audio Engineering Society and European Broadcast Union and used by most forms of digital audio from CDs to D1.
Algorithm:
A step-by-step problem-solving procedure. Transmission of compressed video over a communications network requires sophisticated compression algorithms. Most videoconferencing systems offer both proprietary and standard compression algorithms.
Aliasing:
Defects in the picture caused by too low a sampling rate or poor filtering. Usually seen as "jaggies" or stair steps in diagonal lines.
Analog:
A signal that varies continuously over a range of amplitudes. A digital signal by contrast has only two values, representing 1 or 0.
Artifact:
A visual effect caused by an error or limitation in the system.
Anti-aliasing:
The process of removing aliasing artifacts.
Aspect Ratio:
The ratio of width to height in a picture. Theater screens generally have an aspect ratio of 1.85 to 1, widescreen TV (16x9) is 1.77 to 1, and normal TV (40) is 1.33 to 1.
AST:
Automatic Scan Tracking - Ampex technology which provides "slow motion" capability on professional VTRs and DTVRs.
ATM - Asynchronous Transfer Mode:
A specification from the ISDN standards for providing cell-relay services; a high-bandwidth networking standard.
Auto Assembly:
An edit in which an off-line edit decision list is loaded into an on-line edit computer and all the edits are assembled automatically with little or no human intervention.
Automatic Content Distribution:
Replicates and dispatches content to local workgroup servers, localizing bandwidth consumption and enabling scalability.
AVI:
Audio Video Interleaved: The Video for Windows file format for digital video and audio.
B-Mode Edit:
An editing method where the footage is assembled in the order it appears on the source reels. Missing scenes are left as black holes to be filled in by a later reel. Requires fewer reel changes and generally results in a faster edit session.
Bandwidth:
The amount of information that can be passed through a given circuit or network in a given time. In the case of video, the larger the bandwidth the greater the picture detail can be.
Betacam:
An analog videotape format using 12.5mm tape developed by Sony and derived from the earlier Betamax. Also includes Betacam SP (Superior Performance), and digital versions Digital Betacam and Betacam SX.
Bi-directional Prediction:
A form of compression in which the Indeo® video 4 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 avoid large spikes in data rate caused by scene changes or fast movement, improving image quality.
Bit:
A single element (1 or 0) of digital information.
Bit Rate:
The amount of data transported in a given amount of time, usually defined in Mega (Million) bits per second (Mbps). Bit rate is one means used to define the amount of compression used on a video signal. Uncompressed D I has a bit rate of 270 Mbps. Mpeg I has a bit rate to 1.2 Mbps.
Bit Stream:
A continuous series of bits.
Black Box:
A term used to describe a piece of equipment dedicated to one specific function, also called dedicated hardware.
Blanking:
The part of the video signal that contains no picture information. Used for synchronizing, timecode, closed captions, etc.
Bowser:
Odetics video browsing system that allows the viewer to track and view the material database
BNC:
A bayonet-locking connector for miniature coax; BNC is said to be short for bayonet-Neill-Concelman. Contrast with TNC.
Broadband:
A high-capacity communications circuit/path. It usually implies a speed greater than 1.544Mbps. (Contrast with wideband and narrowband).
Broadcast Quality:
A nebulous term used to describe the output of a manufacturer6s product. Usually at least means that the technical specifications meet the FCC rules for broadcasting.
BRI - Basic Rate Interface (ISDN):
3 digital signals over a single pair of copper wires: 2 voice (B) channels and 1 signal (D) channel. (e.g. voice and fax on a single pair of wires).
Bug:
An error in a computer program. Also something that bites you on a camping trip.
Burned in Time Code:
Time code numbers that are superimposed on the picture. Also called window bum.
Byte 8 bits:
The combination of 8 bits into 1 byte allows each byte to represent 256 possible values. (see Megabyte, Gigabyte, Terrabyte)
Capture:
The process of digitizing the analog video signal. See digitize.
CBR - Constant Bit Rate:
A variety of MPEG video compression where the amount of compression does not change.
CCIR 601:
The standard for digitizing component video. Also sometimes called D I after the VTR format that first used this signal. (see also 4:2:2)
CCITT - Comite Consultatif Internationale de Telegraphique et Telephonique:
An international consultative committee that set 7world-wide communications standards (such as V.21, V22, and X.2~5). Replaced by the ITU-TSS.
Chrominance:
The signal which carries the color information in video.
Cinepak:
A QuickTime codec that is commonly used for CD-ROM video compression. Cinepak allows temporal and spatial compression, as well as data rate limiting.
Coax, Coax Cable:
A high capacity copper-wire cable that carries audio and video signals and radio frequency (RF) energy, consisting of an outer conductor concentric and inner conductor, separated from each other by insulating material. It has more bandwidth than twisted pair, but less bandwidth that fiber-optic cable.
CODEC:
COder/DECoder - Digital encoding/decoding equipment that is necessary to interface analog end-user equipment (such as a television set) to digital transmission facilities. In the case of compressed video, codecs are also used to restore some of the motion which is taken out in the compression process.
Coder:
Also referred to as Encoder and is that portion of the CODEC that digitizes the analog signals to be placed on the digital fiber optic network
Color Frame:
A sequence of four fields (2 frames) of NTSC video. Since the phase of the color subcarrier reverses every frame in NTSC (which makes the color information essentially invisible on a black-and-white receiver) two complete frames are required to carry a complete sequence of color information.
Color Subcarrier:
The portion of the NTSC signal that carries the color information. Color signals are quadrature modulated onto a subcarrier of 3.579545 MHz.
Component Video:
A video signal in which the Luminance and Chrominance signals are kept separate. This requires a higher bandwidth, but yields a higher quality picture.
Compositing Layering:
Multiple pictures on top of each other. A cutout or matte holds back the background and allows the foreground picture to appear to be in the original picture. Used primarily for special effects.
Composite Video:
A video signal format that includes all the visual information in one waveform, including chrominance, luminance, blanking pedestal, field, line, color sync pulses and equalizing pulses. Allows economical broadcasting of video. Compare component video.
Compression:
Methods used to substantially reduce the amount of picture information sent in a video, audio or data signal. A video codec compresses a video signal by only transmitting information about areas of a television picture that change over time or space.
Compression Ratio:
The ratio of the amount of data in the original data compared to the amount of data after compression. The higher the ratio the greater the compression.
Compressed Video:
With compressed video, instead of transmitting a series of full-motion video frames, only the changes in moving frames are captured and transmitted. The reconstituted image exhibits some motion, but, depending on the available bandwidth and the capacity of the transmitters and receivers, motion may appear somewhat irregular. This effect occurs because in compressed video technology the moving areas of the image are only approximated.
Continuous Audio:
The audio connection for a switched video network which allows all connected endpoints to speak at the same time, in the same manner as an audio bridge.
Control Track:
A signal recorded on video tape to allow the tape to play back at a precise speed in any VTR. Analogous to the sprocket holes on film.
CPU-intensive:
Used to describe processes that require large amounts of processor time. CPU-intensive processes usually slow down other processes running on the same computer, and may not run very well, if at all, on slower computers.
CRT - Cathode Ray Tube:
The technical name for a picture tube, a camera tube or the scanning tube in a flying spot telecine.
D1:
Digital video tape format using the CCIR 601 standard to record 4:2:2 component video on 19mm tape. Currently the highest quality video tape format generally available. The first digital video tape format, hence D1.
D2:
Digital video tape format using the 4fsc method to record composite digital video. Uses 19mm tape and a cassette similar to D1. The second digital video tape format, hence D2.
D3:
Digital video tape format using 4fsc composite signals like D2, but recorded on 12.5 mm (1/2-inch) tape. The third digital video tape format.
D4:
Does not exist. The number 4 is considered unlucky in Japan.
D5:
Digital video tape format using CCIR 601, 4:2:2 video. Uses the same cassette as D3. Bet you can guess why it's called D5.
DAC or DCS:
Digital Cross-connect Switch - A remote device (controlled by a central site switch) which can route data, voice, or video signals to a specific destination. A simplified example: suppose phone lines from City A, City B, and City C go to a local DAC and then one line goes from the DAC to the central switch site at City D. A call from City D to City A will be made by the DAC switching the call to the City A circuit. A call from City B to City C will be switched through the DAC and will not use the line to City D (the central switch). The advantage of the DAC is that separate phone circuits are not required from each city to the central switch site; also, this setup prevents every single call from going through the central switch site, thereby relieving traffic.
Data Rate:
The speed of a transfer process, usually expressed in kilobytes (thousands of bytes) per second.
DCT - Discrete Cosine Transform:
A widely used method of video compression. Also an Ampex CCIR 601 digital VTR using DCT to compress the video before recording it to tape.
DDR - Digital Disk Recorder:
A digital video recording device based on high speed computer disk drives. Commonly used as a means to get video into and out from computers and for editing.
Decode:
The process of decompressing a video clip and then converting its color space of from YUV to RGB.
Decompress:
The process of converting video and audio data from its compact form back into its original form in order to play it.
Delta Frame:
A frame containing only the data that has changed since the last frame. Delta frames are an efficient means of compressing image data.
Device Driver:
Software to enable a computer to access or control a peripheral device, such as a printer.
Digitize:
The process of turning an analog signal into digital data.
Digitizing:
The act of taking analog video and/or audio and converting it to digital form. In 8 bit digital video there are 256 possible steps between maximum white and minimum black.
Digital:
A form in which everything is defined by a series of numbers, usually ones and zeros (binary).
Digital Betacam:
Digital video tape format using the CCIR 601 standard to record 4:2:2 component video in compressed form on 12.5mm (1/2-inch) tape.
Digital Video:
A video signal represented by computer-readable binary numbers that describe colors and brightness levels.
Downloadable Video:
: Copying a file from a server to your computer using the network and storing it in memory or on a disk. Downloadable video cannot be viewed in real-time because the video data stream exceeds the network throughput.
Drop Frames:
To fail to play every frame in a video file, usually because of performance limitations of the systems playing the video.
DS-0/DS-3:
Designations given to circuits of different bit rates. A DS-0 circuit has a bit rate of 56 KBs (actually, the full width is 64 KBs, but the rest is used for overhead associated with the transfer). A single digital telephone circuit uses a DS-0. A DS-3 has a bit rate capability of 45 Mbs, which is equivalent to 28 T1 circuits, or 672 DS-0 circuits.
DS-1:
See T-1
DST:
Ampex automated library archive system for broadcast video server applications. DST Systems include tape drives and robotic libraries designed to provide near on-line storage for video servers.
DTF:
Sony video tape product
DVC - Digital Video Cassette:
A digital tape recording format using approximately 5:1 compression to produce near-Betacam quality on a very small cassette. Originated as a consumer product, but being used professionally as exemplified by Panasonic's variation, DVC-Pro, and Sony's variation DVCam.
DVD - Digital Video Disk (or Digital Versatile Disk:
A new format for putting full length movies on a 5" CD using MPEG-2 compression for "much better than VHS" quality.
DVE - Digital Video Effects:
A "black box" which digitally manipulates the video to create special effects, for example, the ADO (Ampex Digital Optics) system. Common DVE effects include inverting the picture, shrinking it, moving it around within the frame of another picture, spinning it, and a great many more.
Edge Numbers:
Code numbers printed on the edge of 16 and 35mm motion picture film every foot which allow frames to be easily identified in an edit list.
EDL - Edit Decision List:
A list of edit decisions made during and edit session and usually saved to floppy disk. Allows an edit to be redone or modified at a later time without having to start all over again.
Embed:
Placing a movie on a web page where it can be viewed without requiring a helper application.
Encode:
In the context of Indeo video, the process of converting the color space of a video clip from RGB to YUV and then compressing it.
Fast start:
See progressive download.
Feedback:
(a) Video - distortion of the picture caused when a video signal reenters the switcher and becomes overamplified; (b) Audio - unpleasant howl from the speaker caused when the sound inadvertently is fed into the microphone and overamplified
Field:
One half of a complete interlaced video picture (frame), consisting of every other row (scan line).
File formats for Video:
ASF, AVI, MP3, and MPEG file formats.
First Name Analysis:
A 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: the color of the chroma-key background, for example. See transparency, transparency frame.
Flatten:
The process of converting a Macintosh file into a self-contained, single-forked file so that it is compatible with a Windows* environment.
fps:
An abbreviation for frames per second, a measure of frame rate.
Frame:
One complete video image, containing two fields. There are 30 frames in one second of NTSC video.
Frame Rate:
Frequency in which video frames are displayed on a monitor, typically described in frames-per-second (fps). Higher frame rates improve the appearance of video motion. Broadcast TV (full motion video) is 30 frames-per-second.
Full-motion Video:
Not compressed. A standard video signal of 30 frames per second and 525 horizontal lines per frame, which is capable of complete action. Level 3 Video utilizing 2 audio channels suitable for use in Distance Education credit courses employing rapid motion (i.e. Grass Valley "E Series" codec and associated equipment).
G2:
RealPlayer file format
Gen-lock:
The synchronization of a piece of video equipment with an external video signal - in video systems.
Gigabyte:
1 Billion bytes.
H.221:
A CCITT standard describing a method in inverse multiplexing for videoconferencing terminals, to be used to Px64 videoconferencing
H.261:
CCITT codec recommendation regarding a video codec for A-V services at p x 64kb/s (p = any integer from 1 to 32); motion compensation and field sub-sampling (loop filter) are implementations optional in the standard
H.320:
A set of CCITT standards describing methods to allow videoconferencing terminals from different manufactures to interoperate.
HDTV - High Definition Television:
A TV format capable of displaying on a wider screen (16x9 as opposed to the conventional 40) and at higher resolution.
Hybrid CD-Rom:
A single disc containing files for both a Windows PC and a Macintosh.
Hybrid Wavelet Transform:
A combination of wavelet and transform algorithms within the same compression technology.
IETF Protocols:
The Cisco IP/TV solution ensures consistent and time-dependent data delivery with RTP and RTCP, and VCR-like media controls with Real Time Streaming Protocols (RTSP).
IMA:
An audio codec which compresses 16-bit audio at a ratio of 4:1.
Indeo Video:
Intel's series of compressor and decompressor technologies for digital video, capable of producing software-only video playback.
The Intelligent Agent:
This is software which does not yet exist; it would create and manage class and field-of-study profiles, conduct sophisticated program searches, and make recommendations to users who request age-appropriate programs or segments. This component represents the primary value-added service of the ECB. This function cannot be done by any other existing agency.
I/O:
Input/Output
Interlace:
A process in which the picture is split into two fields by sending all the odd numbered lines to field one and all the even numbered lines to field two. This was necessary when there was not enough bandwidth to send a complete frame fast enough to create a non-flickering image.
Interframe Compression:
A form of compression in which the codec compresses the data within one frame relative to others. These relative frames are called delta frames.
Intranet:
A large private network, usually found in a corporate or educational environment. Intranets are typically faster and more stable than external networks, such as the Internet.
Intraframe Compression:
A 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.
IP Multicasting:
For schedules or live broadcasts, bandwidth-saving the Cisco IP Multicast permits single-sender and multiple-receiver program transmission. Only one real-time stream of data is sent for each program, no matter how many people tune in.
ISDN Integrated Services Digital Network:
Allows computers to communicate over existing phone lines using a digital telephone network at much higher speeds than are possible with an analog modem. Being used for high quality audio in real-time transfer.
ISO:
International Organization for Standardization compliance
ITS:
The International Teleproduction Society.
ITVA:
The International Television Association.
JPEG - Joint Photographic Experts Group:
A standard for compressing still pictures and video images in a form suitable for frame-by-frame editing.
Keyframe:
Used with delta frames in temporal compression. Keyframes contain the complete video image, while delta frames contain only the changes between keyframes.
Keykode:
A machine-readable code printed on the edge of motion picture film which allows the film edge numbers to be electronically read and inserted in to an edit list. Very useful for generating a negative cut list from a video off-line EDL.
LTC - Linear Time Code:
Time code recorded on a linear analog track on a video tape. Also called Longitudinal Time Code.
Letterbox:
Placing a wide screen image on a conventional TV by placing black bands at the top and bottom of the screen.
Load Balancing:
Directs user requests to the least-busy server within each server cluster, minimizing bandwidth consumption and maximizing performance and scalability.
Local Decode:
A feature of Indeo video interactive allowing the playback application to tell the codec to decode only a rectangular subregion of the source video image: the viewport. See viewport.
Lossless:
Compression algorithms where no data is lost. LOSSIess codecs include the Animation codec and the None codec.
Lossy Compression:
Compression after which some portion of the original data cannot be recovered with decompression. Such compression is still useful because the human eye 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. Cinepak and JPEG are lossy codecs.
Luminance:
The black and white, or brightness, part of a component video signal. Also called the "Y" signal.
Matte:
A black & white high contrast image that suppresses or cuts a hole in the background picture to allow the picture the matte was made from to seamlessly fit in the hole.
MCI:
Media Control Interface: Microsoft's interface for controlling multimedia devices such as a CD-ROM player or a video playback application.
MediaStream:
Pinnacle video server product series capable of over 1,000 hours of online storage
Megabyte:
1 million bytes.
MPEG - Motion Picture Experts Group:
A standard for lossy compression of full-motion video. MPEG 1 uses a data rate of 1.5 Mbps (Mega Bits per Second), the speed of CD-ROM. MPEG 2 supports higher quality with a data rate (also called bit rate) of from 2 to 10 Mpbs. MPEG 2 is the format used for satellite broadcasting (DSS), digital terrestrial broadcasting, and DVD.
Multimedia:
a digital communication medium that is characterized by the juxtaposition of different media including graphics, audio, and video.
Multiplexor (MUX):
A device used for division of a transmission facility into two or more subchannels , either by splitting the frequency band into a narrower bands or by allotting a common channel to several rent transmitting devices one at a time.
Narrowband:
A low-capacity communications circuit/path. It usually implies a speed of 56Kbps or less. (Contrast with wideband and broadband).
Narrowcasting:
As compared to "broadcasting" - television and radio designed to reach small, targeted audiences with an audio or video signal that is transmitted from a central point and can be received by persons around the transmitter using special radio and television equipment. ITFS, cable television, fiber optics and satellite are examples of narrowcast technologies.
Native Resolution:
The resolution at which the video file was captured.
Noise:
Random electrical signal, generated by circuit components or by natural disturbances, that corrupt the data by introducing errors .
Non-Linear Editor:
An editing system based on storage of video and audio on computer disk, where the order or lengths of scenes can be changed without the necessity of re-assembling or copying the program.
NTSC - National Television System Committee:
A standard for color broadcasting developed in the 1950's for use mainly in North America and some of South America. Consists of 525 horizontal lines at a field rate of 60 fields per second. (Two fields equal one complete Frame). Only 486 of these lines are used for picture. The rest are used for sync and extra information such as VITC and Closed Captioning.
OC-3: Network transport capability equivalent to approximately 155Mbps.
Off-Line Editor:
A low resolution, usually computer and disk based edit system in which the creative editing decisions can be made at lower cost and often with greater flexibility than in an expensive fully equipped on-line suite. See also Non-Linear Editor
Off-Line Encoder:
The 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.
On-Line Editor:
An editing system where the actual video master is created. An on-line bay usually consists of an editing computer, video switcher, audio mixer, I or more channels of DVE, character generator, and several video tape machines.
PAL Format:
A color television format having 625 scan lines (rows) of resolution at 25 frames per second (25 Hz).
PAL - Phase Alteration Line:
The standard for commercial television broadcasting in most of Europe, Australia, parts of Central and South America, and other countries. Consists of 625 horizontal lines at a field rate of 50 fields per second. (Two fields equal one complete Frame). Only 576 of these lines are used for picture. The rest are used for sync or extra information such as VITC and Closed Captioning.
Palette Flash:
A phenomenon caused by simultaneously displaying more than one bitmap or video that do not share the same palette.
PALplus:
A widescreen (1 6x9) television standard in use in Europe that is compatible with existing 4x3 TV sets. Non- I 6x9 TVs show the picture in a letterboxed form.
Pixel Short for Picture Element:
The basic unit from which a video or computer picture is made. Essentially a dot with a given color and brightness value. D1 images are 720 pixels wide by 486 high. NTSC images are 640 by 480 pixels.
Picture Element:
The smallest discrete part of a video image, the size of which is controlled by an analog-to-digital conversion sampling process and subsequent other compression processes. The more picture elements per line, the higher the resolution of the image. To convert H Pixels to a close approximation of TV lines of resolution for the NTSC system, simply multiply the number of H pixels by 0.78.
Pixel:
Picture element: the smallest independently accessible unit of a digital image.
Pixel Depth:
The number of bits of color information per pixel. A system using eight bits per pixel can display 256(28) colors. A system using 16 bits per pixel can display 65,536(216) colors. A system using 24 bits per pixel can display over 16.7 million colors. Twenty-four bit 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.
Progressive download:
A component of multimedia architectures such as QuickTime that allows users to watch a video as the file is downloading.
Proximity Management:
Allows configuration of servers into logical groupings or clusters, enabling VOD requests to be directed to the nearest server cluster.
PX64:
Common reference to the CCITT standards (H.261 et. al) which describe methods to allow for video system interoperability
Quick Compressor:
A 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.
Quicktime:
Apple's multimedia environment for its Macintosh operating system.
Quicktime for Windows:
Apple's multimedia playback environment for Microsoft's Windows operating system.
Raw:
A bitstream format in which the video data is uncompressed.
Real Time:
Sending and receiving of messages occurs simultaneously without delay, "live". A transaction which occurs without significant delay from start to finish, i.e., taking a class from a "live" instructor and getting immediate feedback as opposed to watching a videotape of the class sometime after the actual event.
Receive-only Codec:
A video codec configured so as to be able only to receive communications signals and process them for local output, for use at receive locations in point-to-multipoint or for broadcast applications where two-way codec communication with the sending location is not required
Redundant:
Video data information that does not change over time (temporarily redundant) or video data information where a given pixel is surrounded with similar pixels (spatially redundant).
Resolution:
The width and height of the video window, in pixels. The amount of detail in an image. Higher resolution equals more detail. Generally expressed in "lines". It is the number of VERTICAL line pairs that the system can distinguish, and has no relationship to the number of horizontal scan lines. Also used to describe the size of a computer image, usually in pixels.
Resolution Independent:
A term to describe equipment that can work in more than resolution. For example, most equipment can do film resolution or video resolution, but not both. Resolution independent equipment can work in both.
RGB - Red, Green, Blue:
A color model used chiefly for computer displays in which colors are specified according to their red, green, and blue components. Computers and some analog component devices use separate red, green, and blue color channels to keep the full bandwidth and therefore the highest quality picture.
Roswell:
Odetics Facility Management System - Software that automates the acquisition, preparation, media management, and on-air presentation of video and audio material.
RTP:
Real-time Transfer Protocol
Sampling Frequency:
The number of sample measurements taken from an analog signal in a second, generally expressed in MegaHertz. These samples are then converted into digital numeric values to create the digital signal.
Saturation:
The amount of gray, as opposed to hue, in a color-the intensity of the hue.
Scalability:
A 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.
Self-contained:
A MOV file that contains all of its video and audio data, instead of including references to data in other files.
Send-only Codec:
A video codec configuration so as to be able only to originate and transmit communications signals, for use at the sending location in point-to-multipoint or for broadcast applications where 2-way codec communication with the receiving location(s) is not required
Single-forked:
A MOV file whose resources have been moved into the data fork, creating a file that can be played on a PC.
SMPTE - Society of Motion Picture and Television Engineer:
A major standards-setting organization for the motion picture and television industries. Established the standards for time code and for all the major video tape formats.
Spatial compression:
an intra-frame method for compressing video that generalizes an image and removes redundant data.
Standard Compression Algorithm:
An algorithm convention for compression of a video signal. Adherence to standards allows communication among a wide variety of videoconferencing systems, though not with the same clarity as two similar systems using a proprietary algorithm. H.320 is the most widely accepted standard in use today.
Streaming Audio/Video:
Real-time and continuous delivery of video to the desktop. It sends data to the desktop continuously, but does not download the entire file. Some streaming video servers maintain a constant conversation with the client in order to determine how much bandwidth the user can support. Based on this information, the server adjusts the data-stream accordingly and sends just enough video to the client.
StreamWatch:
Cisco software that tracks viewer demographics and help manage, monitor and account for video programs.
T-1:
Telephone term given to a digital transmission circuit whose bandwidth is equal to 24 DS-0 voice channels or 1536 Kbs (actually, 1544 Kbs with 8 Kbs bits used for overhead)
TBC - Time Base Corrector:
A device used in conjunction with a playback from a VCR to provide a sufficient timing stability to permit successful encoding of the video signal by the codec. Some codecs include a built-in TBC.
Telecine:
A device that creates video from motion picture film.
Temporal compression:
In inter-frame method for compressing video that eliminates redundant data across frames.
Terabyte:
1 trillion bytes.
Time Code:
A time reference recorded on tape to identify each frame.
Tracks:
the separate media types that comprise a movie, such as video and audio.
Transparency:
A feature of the Indeo video codec in which software emulates chroma keying, allowing foreground video objects to be composited dynamically over a different background-a bitmap or possibly even another video.
Transparency Frame:
In the transparency technique first-frame analysis, the first frame of the video file. It contains no video data, but merely supplies the color or range of colors to be rendered as transparent. See first-frame analysis, transparency.
Undirectional Predication:
A form of compression in which the codec uses information only from frames that have already been decompressed.
Vaporware:
Software or hardware that is talked about, but may never actually appear.
VBR - Variable Bit Rate:
MPEG video compression where the amount of compression can be varied to allow for minimum degradation of the image in scenes that are harder to compress.
VCR:
Video Cassette Recorder.
VHS:
Video Home System. 1/2-inch consumer video cassette recorder.
Video:
The demodulated and displayed electronic signal which is reconstructed as a viewable picture by a transducer, such as a TV set; the picture is extracted from an analog or digitally encoded carrier wave used to facilitate transmission
Video Archive/Library Providers:
Ampex, StorageTek
Video Archive Management/Automation Software Providers:
Odetics, Louth, Excalibur, Virage,
Video Encoder Providers:
Lucent, Vela, Barco
Video Server Software Providers
: Avalon, Discreet Logic, Oracle, Philips, Legato, Kodak, LSC
Video Server Providers:
EMC, Grass Valley, Pinnacle/HP, SeaChange, Leitch, Pluto
Viewport:
A rectangular subregion of the video image that is displayed using local decode.
VITC -Vertical Interval Time Code:
Timecode stored in the vertical interval of the video signal. Has the advantage of being readable by a VTR in still or jog. Multiple lines of VITC can be added to the signal allowing the encoding of more information than can be stored in normal LTC.
VOD:
Video on Demand allows viewers to request programs at their convenience, yet requires one separate stream of video for each program.
VS-3:
Model number of the Grass Valley equipment that can be used to distribute/switch video signals between the fiber backbone links.
VTR:
Video Tape Recorder.
Wavelet:
A 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 resorted by combining bands sampled at low, medium, and high frequencies.
Wideband:
A medium-capacity communications circuit/path. It usually implies a speed from 64Kbps to 1.544Mbps. (Contrast with broadband and narrowband).
YUV:
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
YVU9:
A 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.
YVU9C:
A 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. This format should only be used when compressing video with Indeo video 3.2. Newer Indeo video codecs provide the option to "Quick Compress" the source video.
For more information please contact:
Evans Associates
210 South Main Street
Thiensville, Wisconsin 53092
(262)242-6000
fax: (262)242-6045
http://www.evansassoc.com
These pages produced and copyrighted by Evans Associates ©, Consultants In Telecommunications Technology, Thiensville, Wisconsin.