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Video Terminology

Defining some terms you may need to know before you buy anything in the DTV/HDTV world.

    1080i
1080i refers to the number of interlaced pixel scan lines appearing on a screen - 1,080. An interlaced screen has 1,080 vertical pixels by 1,920 horizontal pixels. Interlaced scanning "paints" the picture on the screen by first filling in all the odd-numbered scan lines then filling in all the even-numbered scan lines. Done very quickly, the eye only sees one picture on the television. Unlike progressive scanning, which fills in each line before proceeding to the next line, interlaced scanning is not as stable and prone to artifacting.

    16:9
Ratio of the widescreen television screen. For example, for every 16 inches wide, a 16:9 screen is 9 inches high. Also known as 1.78:1 in the film world, most movies are shown in 16:9 format, which means that a movie shown in a theater will be accurately reproduced on a 16:9 widescreen television screen without compression or cropping. Virtually all plasma, lcd and rear-projection televisions are 16:9 format. In contrast, traditional televisions are 4:3 ratio.

    2/3 Pulldown
Digital technology developed by Faroudja to accurately convert and display movie pictures filmed at 24 frames per second on the standard framerate for television broadcasts of 30 frames per second.

    3/2 Pulldown
Same as 2/3 pulldown.

    4:3
4:3 refers to the standard ratio for traditional televisions. For example, for every 4 inches wide, a 4:3 screen is 3 inches high.

    480i
480i refers to "480 interlaced", a form of standard definition digital television broadcast that approximates the quality of analog television but is not considered high definition.

    480p
480p refers to "480 progressive", a form of standard definition digital television broadcast comparable to computer displays but not considered high definition. Each line of the screen is painted before the next line.

    720p
720p refers to "720 progressive", a form of high definition digital television that comprises 720 vertical pixels by 1,280 horizontal pixels. Scanning is done by painting a line of pixels before the next one is painted. Because of the sequential scanning, 720p is better able to handle motion and is actually superior to 1080i for that reason.

    Analog
Refers to the way cable broadcasts are transmitted directly from the television wall cable to the television.

    Anamorphic
Describes the way 16:9 films are compressed to be shown on a 4:3 television screen with black bars on the top and bottom of the picture.

    Anamorphic Downconversion
Processing present in all dvd players where an anamorphic film is "fitted" onto a 4:3 television screen.

    Anti-Reflection Screen Coating
The coating on a television screen which absorbs light and resists its reflection. Helps to keep the image clear to the viewer.

    Artifact
An abnormality in a video image resulting in a temporary, visual distortion. Also known as "pixelation" since the individual pixels can be briefly seen.

    Aspect Ratio
Refers to the relationship between the width and height of a television screen. A standard television has an aspect ratio of 4:3 while a widescreen television has an aspect ratio of 16:9.

    Audio Input
Refers to the part of the television where connections to audio components such as a receiver can be made.

    Black Level
Refers to the intensity of black in a picture. If not set correctly, picture detail quality will be poor in dimly lit scenes of a movie. Also refers to the ability of the display to produce a dark, deep shade of black. This is often a problem in plasma and lcd displays.

    Burn-in
Refers to an uneven use of pixels caused by excessively bright and stationary images which results in a permanent ghosted shadow.

    Cathode Ray Tube
The classic-type television with an electron gun at the back of a vacuum enclosure.

    Chrominance Signal
Technical name for the signal that carries the color information (red, green and blue) required to display a color image.

    Color Temperature
Otherwise called white balance, color temperature is expressed in degrees kelvin or just Kelvins. Color temperature refers to the color of gray at different levels from black to white. Since color information overlays the black-and-white information in a TV signal, color temperature affects the entire range of color. The National Television Standards Committee (NTSC) standard is 6,500K, but typically manufacturers ship their TVs with color temperatures ranging from about 7,000K to 12,000K, on the blue side of the color spectrum, to make sets as bright as possible to stand out on a brightly lit showroom sales floor.

    Comb Filter
Component in all televisions that separates the color information in a signal from the brightness information.

    Component Video Input [Y, PB(CB), PR(CR)]
A type of superior video input used for DVD players and some game consoles. Picture quality is superior to s-video, composite and antenna-in.

    Compression
Refers to the reduction in the number of bits required to store or transmit data. The method adopted for digital television is called MPEG-2.

    Contrast Ratio
The brightness of a display at full white over the brightness of a display at full black. Because the black value is greatly affected by ambient light, some TV technologies calculate contrast ratio in darkened rooms.

    Digital Cable Ready
Official term for a high definition television that conforms to plug-and-play digital cable TV standard using "point of deployment" access cards (a/k/a CableCARDs). A digital cable ready-TV allows users to plug the cable directly into an HDTV set and enjoy HDTV and digital cable without having to use a separate set-top box. If there is also interactive functionality built into the set, it is labeled Interactive Digital Cable Ready.

    Digital Comb Filter
See comb filter definition.

    Digital Light Processing (DLP)
Technology developed by Texas Instruments that is based on a digital micromirror device (a chip with millions of microscopic, hinged mirrors). Red, green and blue light is filtered through a color wheel and directed alternately onto the DMD, which switches on and off up to 5,000 times a second. The reflected light is directed through a lens and onto a screen, creating the image. High end HDTV projectors use three DMDs and forgo the color wheel--each DMD corresponds to a separate color (red, green and blue).

    DirecTV
A major satellite television provider which broadcasts several channels in high-definition.

    Dish Satellite TV
Another major satellite television provider which also broadcasts several channels in high-definition.

    Dolby Digital (AC-3)
Refers to the standard under which digital surround sound is broadcast. Dolby Digital is a 6-channel standard corresponding to a center channel, two side front channels, two rear side channels and a subwoofer channel.

    Down Convert
Refers to the conversion of a high-resolution broadcast to a lower resolution broadcast. For example, some DTV receivers can be set to downconvert an HDTV 1080i signal to a standard 480i signal that any TV can display.

    DTV
DTV is the acronym for Digital Television. Digital television comes in three, increasing quality standards: standard definition, enhanced definition and high definition.

    DVI Interface
Digital Visual Interface - a type of standard connector between the display and a computer or other device. DVI images are superior to composite video and s-video signals.

    DVR
Refers to "digital video recorder", also known as "personal video recorder". A DVR or PVR records broadcasts on a hard disk drive which can then be played back at a later time (this is known as "time shifting"). The most well known DVR is the TiVo.

    EDTV
Refers to enhanced definition television. EDTV is a broadcast standard that produces 852x480 pixel resolution images. EDTV broadcasts are superior to standard definition broadcasts but not as good as high definition broadcasts.

    EPG
Refers to "electronic programming guide". This feature is found on satellite and cable tuner boxes and DVRs, and increasingly on TVs and DVD recorders and provides an onscreen listing of available channels and program data for an extended time period (e.g. 36 hours or more).

    F.C.C.
Federal Communications Commission - Federal governmental agency responsible for the regulation of broadcast television in the United States.

    Flat Panel Television
Term used to refer to televisions that are modularly thin. Plasma screen displays and LCD TVs are the two types of flat panel televisions.

    Flat Screen Television
Term used to refer to televisions whose display screen is "flat" instead of curved at corners and edges.

    Frame Rate (FPS)
Refers to the number of individual still pictures that pass by every second to create a moving image. Films run at 24fps, while video, including DVD, runs at 30fps. To compensate for the difference, 2:3 pull-down detection is used.

    Front Projection
Type of television system whereby an image is projected onto a screen or a wall. The image size is variable depending on the distance of the projector from the screen or wall.

    Ghosting
Refers to the effect where multiple overlaid TV images are noticeable around the edges of objects. This occurs when the antenna picks up multiple signals in addition to the original signal due to reflection from objects or other distortions. Also refers to the image left on a screen as a result of burn-in.

    Grayscale
Range of gray at different intensities from completely black to completely white.

    HDMI / HDCP Interface
USB-like connection that can transmit both uncompressed digital audio and video signals while simultaneously adhering to the High-bandwidth Digital Content Protection (HDCP) standard.

    HDTV
Acronym for "high definition television", the highest of the digital television standards. HDTV displays pictures either in 720p or 1080i.

    HDTV-Ready
Refers to any television that would be capable of receiving high definition signals, provided that an additional receiver is also connected. An HDTV-ready television requires an HDTV receiver in order to receive and decode high definition signals.

    HDTV Receiver
Device that receives and decodes high definition signals. An HDTV receiver is required to be connected to an HDTV-ready TV in order for the TV to receive high definition signals.

    HDTV Tuner
Same as an HDTV receiver.

    Horizontal Resolution
Number of vertical lines (or pixels) that can be resolved from one side of an image to the other. While the vertical resolution of all analog video sources is the same (480 lines), the horizontal resolution varies according to the source. Some examples for typical sources: VHS VCRs (240 lines), analog TV broadcasts (330 lines), non-HDTV digital satellite TV (up to 380 lines), and DVD players (540 lines). DTV signals have horizontal resolution that ranges from 640 lines for SDTV to 1,280 lines (for 720p HDTV) or 1,920 lines (for 1080i HDTV). (Definition properly attributed to CNET.)

    Integrated Speaker System
Refers to speakers built into the television. Many plasma and LCD models do not come with integrated speakers. Therefore, it is important to note whether this feature is included before purchasing. Otherwise, separate speakers will need to be purchased.

    Interlacing
Refers to scanning method used by the majority of televisions and the 1080i HDTV format. Interlacing involves painting the odd-numbered lines of a screen in succession, then going back and filling in all the remaining even-numbered lines. As opposed to progressive scanning in which all the lines are painted in sequence, interlacing is more prone to artifacts and is less stable than progressive.

    LCD
Refers to liquid crystal display technology, one of the two most popular technologies behind flat panel televisions (the other being plasma). Liquid crystal display technology works by blocking light from a high intensity source in order to display a picture. Liquid crystals are sandwiched between two glass plates and minor temperature variations are introduced to particular points causing the crystals to change colors in predetermined patterns.

    LCoS
Refers to "liquid crystal on silicon", a newer form of liquid crystal technology. Whereas liquid crystal in an LCD screen is sandwiched between two transparent plates, LCoS involves liquid crystals placed on silicon, a hoped-for cheaper manufacturing alternative.

    Letterbox
Refers to a way that wide-screen images are displayed on a standard 4:3 screen. In letterbox format, the image is bounded by black bars on the top and bottom to create a widescreen image.

    Line-doubler/tripler/multiplier
Technology used to create a higher-quality picture by increasing the number of lines of resolution displayed.

    Lumens
The unit of measure for the light output of a projector.

    Mpeg-2
Refers to Moving Picture Experts Group-2, a video-compression scheme used to condense digital video content for broadcast over thin TV bandwidths or via the Internet, and to squeeze full-length digital films onto a DVD.

    Native Resolution
Refers to the resolution at which a TV or monitor is designed to display images without conversion. Image signals higher or lower than a specified native resolution must be converted to display accurately. For example, a television with a native resolution of 1080i will need to upconvert 480p images to 1080i to display properly. CRT TVs can have multiple resolutions but flat panel TVs can only have one native resolution.

    NTSC
Acronym for National Television Standards Committee, the FCC engineering group formed in 1940 to develop technical standards for black-and-white television (NTSC broadcasting began July 1, 1941) and color television (1953). NTSC developed the video-transmission standard used in the western hemisphere, Japan, and other Asian countries. NTSC standards are 525 lines of resolution transmitted within a 6MHz channel at 30fps.

    OSD
Refers to "on-screen display" program setup. OSD allows one to view and change settings displayed on the television screen.

    Over the Air Broadcast
Refers to any broadcast signal received by the television other than from subscriber satellite or cable.

    PAL
Acronym for Phase Alternating Line, the video-transmission standard introduced in the early 1960s and used in most European countries except France and the former Soviet Union. PAL standards specify 625 lines of resolution at 50fps.

    Picture-in-Picture (PIP)
Refers to the ability of newer television models to display two channels at once. PIPs are usually displayed as a small rectangular screen within the main TV screen or two images side-by-side.

    Pixel
Refers to the smallest points of color on a screen, composed of separate red, green and blue subpixels that combine to create an image.

    Pixel Pitch
Refers to the distance between pixels. The lower the pixel pitch, the sharper the image.

    Plasma
Refers to the display technology in plasma televisions. Each plasma panel contains thousands of tiny tubes filled with ionized gas that, when excited by electricity, glow in different colors and intensities to create an image.

    Progressive Scan
Scanning method whereby each row of pixels is sequentially scanned as opposed to interlaced scanning whereby all odd pixels are scanned, then all even pixels.

    PVR
Same as DVR.

    Rear-Projection
Type of television where an image is projected from the rear of the television cabinet onto a screen at the front. The two most popular types of rear-projection TVs are based on one of two technologies - LCD or DLP.

    Red Push
Refers to the tendency of a television's color decoder to accentuate the color of red as compared to blue and green. Typically, this is intentionally caused to compensate for an overly blue color temperature.

    Response Time
Response time is a measure of how long a display takes to change the image. A typical LCD television is 2 to 3 times faster than the average computer monitor LCD. Fast response time is superior for playing computer games and viewing action movies and sports.

    Resolution
Refers to the number of pixels a television is capable of displaying. A higher resolution usually corresponds to a sharper image.

    S-Video
A type of connection that separates the color data from the brightness data entering into a television from an external device such as a DVD player.

    SDTV
Refers to standard-definition television, a digital television format that includes 480-line resolution in both interlaced and progressively scanned formats. Similar to DVD or satellite TV in quality, it is not considered high definition television.

    Surround Sound
See Dolby Digital.

    TiVo
A popular manufacturer of digital video recorders.

    Up Conversion
Refers to the conversion from a lower-resolution input signal to a television capable of receiving higher resolutions. For example, a conversion from an SDTV source signal of 480p to HDTV 1080i on an HDTV television is an up conversion.

    V-Chip
Canadian-invented electronic component that allows television broadcasts to be filtered according to ratings criteria. V-Chips are typically marketed as a parental control on the types of television children can watch.

    Vertical Compression
 Feature found on 4:3 TVs designed to take advantage of the extra resolution in anamorphic DVDs and other wide-screen content. Pioneered by Sony, this feature squeezes the TV raster so that the electron beam scans in a smaller area. It requires setting the DVD player to 16:9 mode, eliminates anamorphic downconversion artifacts, and ideally provides a 33 percent increase in resolution in the letterboxed image. (Definition from CNET.)

    Vertical Resolution
Refers to the number of horizontal lines (or pixel rows) from the top of the television screen to the bottom.

    Voom Satellite TV
Upstart satellite TV broadcaster. Competitor to DirecTV and Dish Network.

    Widescreen
Term used to refer to 16:9 screen ratio.

    Windowbox Bars
Refers to the blank bars (usually black in color) on each side of a 4:3 image displayed on a 16:9 widescreen television.

    Y Pb Pr, Y Cb Cr, Y R-Y B-Y
Technical shorthands for component video.