Anamorphic video: Video images that have been "squeezed" to fit a video frame when stored on DVD (These images must be expanded by the display device). An increasing number of TVs employ either a screen with 16:9 aspect ratio, or some type of "enhanced-for-wide-screen" viewing mode, so that anamorphic and other wide screen material can be viewed in its proper proportions. When anamorphic video is displayed on a typical TV with 4:3 screen size, the images will appear unnaturally tall and narrow.

Aspect ratio: The ratio of width to height for an image or screen. The North American NTSC television standard uses the square 4:3 (1.33:1) ratio. More and more direct-view and projection TVs (especially digital TVs) use the wider 16:9 ratio (1.78:1) to better display wide screen material like anamorphic DVDs and HDTV broadcasts.

Bitrate: Measured as "bits per second," and used to express the rate at which data is transmitted or processed. The higher the bitrate the more data is processed and typically the higher the picture resolution. Digital video formats typically have bitrates measured in megabits-per-second (Mbps). (One megabit equals one million bits.) The maximum bitrate for DVD playback is 10 Mbps; for HDTV it's 19.4 Mbps.

Component video: The three-jack component video connection splits the video signal into three parts (one brightness and two color signals). Component video has increased bandwidth for color information, resulting in a more accurate picture with clearer color reproduction and less bleeding. A growing number of TVs include component video jacks to provide the best possible picture quality (better than S-video or composite video) when connected to a compatible DVD player.

CRT: Stands for cathode ray tube. A CRT ("picture tube") is a specialized vacuum tube in which images are created when an electron beam scans back and forth across the backside of a phosphor-coated screen. Each time the beam makes a pass across the screen, it lights up a horizontal line of phosphor dots on the inside of the glass tube. By rapidly drawing hundreds of these lines from the top to the bottom of the screen, images are created. The regular "direct-view" TVs that most people watch have a single large picture tube, while CRT-based rear-projection and front-projection TVs use three CRTs: one each for red, green, and blue.

De-interlacing (also called line-doubling): The process of converting an interlaced-scan video signal (where each frame is split into two sequential fields) to a progressive-scan signal (where each frame remains whole). De-interlaces are found in digital TVs and progressive-scan DVD players. More advanced de-interlaces include a feature called 3-2 pull down processing. For TVs, de-interlacing is often referred to as "line-doubling" or "up conversion."

Digital audio output: A connection found on HDTV's and HDTV tuners for sending the Dolby Digital audio of HDTV broadcasts to an A/V receiver with Dolby Digital decoding. The two most common types of digital output are coaxial and Tos-link optical.

Dolby® Digital: A discrete multi-channel digital audio format that is the official audio standard for HDTV (and DVD). Dolby Digital is normally associated with 5.1-channel surround sound. Though this channel configuration is common, it is only one of several possible variations - a "Dolby Digital" soundtrack can mean anything from 1 to 5.1 channels.

Down convert: A term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display. Some HDTV tuners are able to down convert digital HDTV signals for display on a regular analog TV.

DTV (Digital Television): The new American digital broadcast TV standard, which began operation in late 1998, and will eventually replace the 60-year-old analog NTSC system. DTV comes in two basic types: wide screen, near-film-quality HDTV (High-Definition Television) with Dolby Digital audio, and medium-quality SDTV (Standard-Definition TV).

DVI (Digital Visual Interface): A multi-pin computer-style connection intended to carry High-Definition video signals from digital set-top boxes (HDTV-capable DIRECTV, DISH Network, and cable boxes) to HDTV monitors with a compatible connector. The signals are encrypted with High-bandwidth Digital Content Protection (HDCP) to prevent recording.

EDTV (Enhanced Definition Television): Some manufacturers are offering digital televisions that have excellent resolution of 480 progressively scanned lines (480p) compared to the 720 progressively scanned lines required to qualify as true "high definition." EDTV sets will take a high definition signal from an antenna, satellite receiver or cable box and "downconvert" it to 480p, resulting in a picture that is close to HD but typically at a lower price. A good application of an EDTV set would be for watching DVDs, since they have about 480 lines of resolution and will not be enhanced by a true high-definition set.

HDTV (High-Definition Television): Often mistakenly used as a generic description of all digital television, HDTV specifically refers to the highest-resolution formats of the 18 total DTV formats. Although there still isn't 100% agreement among manufacturers, retailers, journalists, etc., true HDTV is generally considered to be 1,080-line interlaced (1080i) or 720-line progressive (720p).

HDTV-ready: Term used to describe TVs, which can display digital high-definition TV formats when connected to a separate HDTV tuner. These TVs generally have built-in tuners for receiving regular NTSC broadcasts, but not digital. An HDTV-ready TV may also be referred to as an "HDTV monitor."

Letterboxed video: A method for displaying the entire picture as seen in a movie theater. The resulting image width is much greater than its height. On a TV screen with standard aspect ratio (4:3), letterboxed videos appear with horizontal black bars above and below the image.

Luminance: The brightness or black-and-white component of a color video signal. Determines the level of picture detail.

MHz (Megahertz): Equal to one million Hz, Video signal bandwidth is typically expressed in megahertz.

MPEG-2: The video compression standard used for digital television, DVD, and small-dish satellite TV. This adaptive, variable bitrate process is able to allocate more bits for complex scenes involving a lot of motion, while reducing the bits in static scenes. MPEG stands for Moving Picture Experts Group.

MTS (Multi-channel Television Sound): The method of broadcasting stereo sound over ordinary analog TV channels. MTS reception capability is built into virtually all stereo TVs and HiFi VCRs.

NTSC: Stands for National Television System Committee, which established our North American 525-line analog broadcast TV standard about 60 years ago. Although it is referred to as a "525-line" standard, we're only able to see 480 lines on a TV display. The new DTV digital broadcast standard will eventually replace NTSC.

Pan-and-scan (4:3 Aspect Ratio): The process of transferring a movie or other source material to videocassette, DVD, or broadcast so that it fits the 4:3 aspect ratio of the NTSC system, as well as most current TVs. This results in a significant amount of lost picture information, particularly in the width of the image. At the beginning of a movie on videocassette, you'll usually see a disclaimer about the movie having been "...formatted to fit your TV." That means it's been converted to pan-and-scan.

Picture-in-picture (PIP): There are two basic types: 1-tuner picture-in-picture models require that you connect a VCR or other video component to provide the source for your second picture. 2-tuner picture-in-picture models have two built-in TV tuners, so you can watch two shows at once using only the TV.

Progressive scan: Some digital television broadcast formats (720p, 480p), and some higher-end DVD players, use a type of video signal known as progressive scan. Instead of splitting each video frame into two sequential fields like standard interlaced NTSC video, progressive-scan video displays the entire frame in a single sweep. So, where standard NTSC video displays 30 frames (60 fields) per second, progressive scan displays 60 full frames per second.

Rear-projection TV: Typically referred to as "big-screen" TVs, these large-cabinet TVs generally have screens measuring at least 40". Until recently, all rear-projection TVs used three CRTs, which projected images against a mirror inside the cabinet, so that the images were then reflected onto the built-in screen. New and innovative rear-projection technologies include LCD, and DLP.

SDTV (Standard-Definition Television): A digital television system that is similar to current standards in picture resolution and aspect ratio. The picture and sound will be clearer than NTSC, and its digital base will allow more than one program to be broadcast over the same bandwidth at the same time. Typical SDTV resolution is 480i or 480p.

Set-top box (STB): Also called converter boxes, these receivers convert broadcasts (either analog cable, digital cable, or HDTV) for display on a television. HDTV-ready TVs (those without a built-in HDTV tuner) must be connected to a compatible HDTV tuner set-top box in order to receive digital television programs.

S-video: Found on nearly all of the TVs we sell, this 4-pin connector usually provides a sharper, higher resolution picture by transmitting the chrominance and luminance portions of a video signal separately. The signals can then be processed separately, reducing interference. Direct S-video connections generally outperform composite connections when hooking up high-performance video components like DVD players, DBS receivers, and S-VHS and Hi8 recorders and camcorders.

Wide-Screen (16:9 Aspect Radio): When used to describe a TV, wide screen refers to an aspect ratio of 16:9, which is the optimum ratio for viewing anamorphic DVDs and HDTV broadcasts.

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Last updated 5/11/06. Written By Mark Cook. Copyright Abt Electronics, Inc. 2006