TV  video Camcorder DigiCam Media Audio Theater Help companies  



Tv Glossary





Introduction Links Formats Features
l l Media Models

 Consumer Video

TV HDTV Glossary

See aspect ratio, and widescreen.

3-2 pulldown processing
Video processing common to digital TVs and progressive-scan DVD players. 3-2 pulldown  corrects for artifacts and distortion that occur when film-based material (24 frames per second) is converted to video (30 frames per second), then de-interlaced to create a progressive-scan signal. 

See aspect ratio.

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. When anamorphic video is displayed on a typical TV with 4:3 screen size, the images will appear unnaturally tall and narrow.

Unwanted visible effects in the picture created by disturbances in the video transmission or processing. Examples include "dot crawl" in analog pictures, or "pixelation" in digital pictures.

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

Advanced Television Standards Committee. Formed to establish technical standards for the U.S. digital television system.

Audio/video inputs
Using a TV's A/V inputs to connect a DVD player, VCR, camcorder or other video component provides improved picture and sound quality compared to using the one-wire RF antenna-style input. 

Rear A/V inputs are used for components you normally leave connected to your TV. Front A/V inputs allow you to quickly connect / disconnect a camcorder.

Audio outputs
Stereo audio jacks that let you connect your TV to your stereo or home theater system. There are two types, fixed and variable. 

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 that is processed. Digital video formats typically have bitrates measured in megabits-per-second (Mbps). The maximum bitrate for DVD playback is 10 Mbps; for HDTV it's 19.4 Mbps.

The color component of a video signal that includes information about hue (shade) and saturation (intensity).

Comb filter
A comb filter removes residual chrominance (color) information from the luminance (brightness) signal. Comb filtering enhances fine detail, cleans up image outlines, and eliminates extraneous colors. Comb filters are not required and not used with S-video or component video connections since those connections carry the chrominance and luminance information separately. 

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. 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.

Special wide-bandwidth component video connections are capable of carrying wider bandwidth video signals, like progressive-scan DVD and digital television.

All HDTV-ready TVs include at least one set of wide-bandwidth connections for connecting a HDTV tuner or progressive-scan DVD player.

Composite video
A single video signal that contains luminance (brightness) and chrominance (color) information. A composite signal is better than an RF signal, but not as good as S-video or component video. A composite video jack is usually a single yellow RCA-type.

Cathode ray tube. A CRT (picture tube) is a  vacuum tube in which images are created when an electron beam scans back and forth across the back side 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.

De-interlacing (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-interlacers are found in digital TVs and progressive-scan DVD players. More advanced de-interlacers include a feature called 3-2 pulldown processing. For TVs, de-interlacing is often referred to as "line-doubling" or "upconversion."

Digital audio output
A connection found on HDTVs and HDTV tuners for sending the Dolby Digital 5.1 audio of HDTV broadcasts to an A/V receiver with Dolby Digital decoding. The two most common types of digital output are coaxial and optical.

Direct-view TV
The conventional and most common type of TV, which uses a single large CRT to display images. 

DLP (Digital Light Processing)
A projection technology developed by Texas Instruments, based on their Digital Micromirror Device (DMD) microchip. Each DMD chip has hundreds of thousands of tiny mirrors which are used to create the image. DLP technology is used in both front- and rear-projection systems.

There are two basic types of DLP projector: "single-chip" projectors use a single DMD chip along with a spinning color wheel, while much more expensive "3-chip" projectors dedicate a chip to each basic color: red, green, and blue.

Dolby® Digital
A 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.

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 downconvert digital HDTV signals for display on a regular analog TV.

DTV (Digital Television)
The 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 flavors: widescreen, HDTV (High-Definition Television) with Dolby Digital audio, and medium-quality SDTV (Standard-Definition TV).

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

Electronic program guide
EPG provides an on-screen listing of all available programming for an extended time period (typically 36 hours or more).

In interlaced-scan video, each complete frame is split into 2 sequential fields, each of which contains half the scanning lines of the frame. One field contains the odd scanning lines, and the other field the even lines.

A complete, individual picture in a movie. In a video signal, a frame contains all of the picture's scanning lines. The frame rate of a progressive-scan format is twice that of an interlaced-scan format.

Frame rate
The rate at which frames are displayed. The frame rate for movies is 24 frames per second (24 fps). In regular NTSC video, the frame rate is 30 fps. The frame rate of a progressive-scan format is twice that of an interlaced-scan format — example: the frame rate for 480i DVD is 30 fps (or 60 interlaced fields per second); for progressive-scan DVD at 480p, 60 fps.

Front-projection TV
A 2-piece display system consisting of a separate projector (often ceiling-mounted) and screen. Generally found in high-end home theaters, front-projection systems can display images up to 20 feet across, or larger. Types of front projectors include CRT, LCD, and DLP.

HDMI (High-Definition Multimedia Interface)
Audio Video connection for standard and high definition digital audio and video. Uses a multi-pin cable capable of 720p, 1080i, 1080p High Def video and up to 8 channel digital audio. The interface has undergone many revisions with increasing capabilities. Cable connections are Type A (19 pin), Type B (29 pin) and Type C (mini version for portable devices). Found on DVD, HDTV, camcorders and set-top-box devices.

HDTV (High-Definition Television)
HDTV refers to the highest-resolution formats of the 18 total DTV formats. True HDTV is generally considered to be 1,080-line interlaced (1080i) or 720-line progressive (720p) or 1,080-line progressive (1080p).

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 NTSC broadcasts, but not digital. An HDTV-ready TV may also be referred to as an HDTV monitor.

IEEE 1394 (FireWire or i.LINK)
First conceived by Apple Computer (as FireWire®), then developed by the IEEE (Institute of Electrical and Electronics Engineers), this high-speed 2-way connection allows easy transfer of digital data between electronics gear and computers. Found on some HDTV-capable TVs, tuners, and recorders.

Interlaced scan
Interlaced scan refers to the process of re-assembling a picture from a series of video signals. The NTSC system uses 525 scanning lines to create a picture (frame). The frame/picture is made up of two fields: The first field has 262.5 odd lines (1,3,5...) and the second field has 262.5 even lines (2,4,6...). The odd lines are scanned in 1/60th of a second, and the even lines follow in the next 1/60th of a second. This presents an entire frame/picture of 525 lines in 1/30th of a second.

Analog NTSC video uses interlaced scanning, as do several digital television formats. Formats that include an "i" (1080i, 480i) use interlaced scanning. See also progressive scan.

LCD (Liquid Crystal Display)
Liquid Crystal Display technology is one of the methods used to create flat-panel TVs. Light isn't created by the liquid crystals; a light source (CCFT bulb) behind the panel shines light through the display. The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. The pattern of transparent and dark crystals forms the image.

LCD technology is used in direct-view, rear-projection, and front-projection TVs, and is fundamentally different from the CRT technology used in conventional TVs.

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.

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.

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

National Television System Committee, which established 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.

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.

Short for picture element. The smallest bit of data in a video image. The smaller the size of the pixels in an image, the greater the resolution.

Gas-plasma technology is one of the methods used to create flat-panel displays. Besides enabling thin, lightweight TVs that can be hung on a wall, plasma offers other advantages. The display consists of two transparent glass panels with a thin layer of pixels sandwiched in between. Each pixel is composed of three gas-filled cells or sub-pixels (one each for red, green and blue). A grid of tiny electrodes applies an electric current to the individual cells, causing the gas to ionize. This ionized gas (plasma) emits high-frequency UV rays which stimulate the cells' phosphors, causing them to glow, which creates the television image.

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. Where standard NTSC video displays 30 frames (60 fields) per second, progressive scan displays 60 full frames per second.

Displaying progressive-scan video requires more bandwidth (there's twice as much vertical information) and a faster horizontal scan frequency than interlaced video. For progressive-scan viewing, you'll need a TV that's HDTV-ready.

Rear-projection TV
Typically referred to as "big-screen" TVs, these large-cabinet TVs generally have screens measuring at least 40". In the past, 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. Newer rear-projection technologies include LCD, and DLP.

The sharpness of a video image, signal or display, described either in terms of "lines of resolution," or pixels. The resolution you see depends on two factors: the resolution of your display and the resolution of the video signal. Since video images are always rectangle-shaped, there is both horizontal resolution and vertical resolution.

  • Vertical resolution: The number of horizontal lines (or pixels) that can be resolved from the top of an image to the bottom. The vertical resolution of the standard analog NTSC TV standard is 525 lines. But, some lines are used to carry other data like closed-captioning text, test signals, etc., so we end up with about 480 lines in the final image, regardless of the source. All of the typical NTSC sources — VHS VCRs, cable and over-the-air broadcast TV (analog), non-HD digital satellite TV, DVD players, camcorders, etc. — have vertical resolution of 480 lines. DTV (Digital Television) signals have vertical resolution that ranges from 480 lines for SDTV, to 720 or 1080 lines for true HDTV.
  • Horizontal resolution: The number of vertical lines (or pixels) that can be resolved from one side of an image to the other. 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 and 1,920 lines for 1080i HDTV.

SDTV (Standard-Definition Television)
A digital television system that is similar to NTSC 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.

This 4-pin connector 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. 

The conversion of a lower resolution to a higher one. This process increases the number of pixels and/or frame rate and/or scanning format used to represent an image by interpolating existing pixels to create new ones at closer spacing. 

Widescreen refers to an aspect ratio of 16:9, which is the optimum ratio for viewing DVDs and HDTV broadcasts.



How to get HDTV ..

Learn about the various tv formats:
TV formats
Learn about tv features:
TV features
How do I get HDTV: