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

1080i

This is an interlaced format — for more information see “interlaced scanning” and “de-interlacing”. This format has 1080 lines at either 50 or 60 Hertz. 50 Hertz is sometimes also described as 1080i/25 and, in the same way, 60 Hertz can be called 1080i/30, in reference to the number of full-frame images. Most European HDTV broadcasters use 1080i.

1080p

This is the standard format for images in Progressive Scan format at a resolution of 1,920 x 1,080 pixels, transmitted at either 50 or 60 Hertz.
Screens that can display this resolution also often bear this abbreviation. The current HDTV technology is not designed for 1080p, so no one is currently broadcasting in this format.

24p

In 24p, the video’s frame rate exactly matches that of the original film recording. Traditionally, this is converted to 60 Hertz material by repeating the film frames three times and two times alternately (this is a so-called “3:2 Pulldown”). With Blu-ray movies and suitably equipped players, this conversion does not take place, so motion looks just as it did on the big screen.

The problem here is that some TVs will accept 24p signals, but will show irregular 3:2-Pulldown judder, as if the signal had been converted to 60 Hertz. Alternatively, they may use internal motion enhancement circuits that ruin the movie-feel by eliminating judder altogether.

25p

Another standard for European TV productions. This is supposedly also possible on Blu-ray, as well as for transmission via HDMI. Canon camcorders also use this standard.

30p

A standard for TV productions in NTSC countries, this is also supposedly possible for transmission via HDMI.

480i

The classical NTSC standard in digital form, with 480 horizontal lines of 720 pixels each (or less) and 60 interlaced pictures per second.

480p

A form of standard-definition signal with 480 horizontal lines of 720 pixels each, broadcast as progressive (full-frame) pictures.

576i

The PAL TV standard in digital form, with 576 horizontal lines of 720 pixels each (or less) and 50 interlaced pictures per second.

720p/24

Anamorphic means distorted. Widescreen movies are distorted by a factor of 1.33 on DVDs so that all pixels are addressed. When switching the format, the anamorphic picture is returned to an undistorted state. A similar technique was used originally in cinemas for the playback of widescreen material shot in 2.35:1 format for more optimized playback of 35mm material. The breakthrough for anamorphic 16:9 images came with the arrival of DVDs and digital television (Digital Video Broadcast, or DVB). HDTV material, by comparison, is only available in the 16:9 format, and is therefore never anamorphic.

anamorphic downconversion:Process for converting anamorphic wide-screen material for display on a 4:3-format screen. All DVD players use this when connected to standard-format TVs.

Aliasing effects

Aliasing effects are artifacts that often result from the digitization of analog signals or because of technical limitations in the signal processing. The phenomenon occurs when superfluous frequencies are present above the highest frequency that the TV can display. The TV then interprets these as lower frequencies: They appear as their alias, so to speak. If, for example, the maximum displayable frequency is at 6.5 MHz, but the incoming images contain some signal components at 7.5 MHz, undesired lines and structures will appear at 4.5 MHz. In other words, if the superfluous frequency is 2 MHz higher than the maximum, the artifacts will appear at precisely 2 MHz below the maximum. Anti-Aliasing is the process used to remove these aliasing effects.

Ambilight

Ambilight is a feature of many TVs from Dutch manufacturer Philips. The system consists of a row of lamps, either based on fluorescent tubes or LEDs, that immerse the area around the TV in soft, colored light. The gentle illumination relieves the viewer's eyes, since the contrast between the bright screen and dark surroundings is no longer as severe. By using red, green, and blue lamps, the Ambilight can change color — if the user wishes, it can even adjust its brightness and color to match the current TV picture.
The idea behind Ambilight is based on so-called “TV lamps”, which used to be fairly common but have now been largely forgotten: These bluish-colored lightbulbs were positioned beside or behind the TV to relieve the viewer's eyes.

Anamorphic

Anamorphic means distorted. Anamorphic 16:9 pictures are found on DVDs, where widescreen movies are distorted by a factor of 1.33 in order to use all available pixels. The TV changes the ratio and returns the anamorphic picture to an undistorted state. Digital TV (Digital Video Broadcast, or DVB) also transmits anamorphic 16:9 pictures. The technique was originally used in movie theaters for widescreen movies in 2.35:1 format.

HDTV pictures, on the other hand, are stored in 16:9 format by default and are never anamorphic.

ANSI

Acronym for American National Standards Institute, a US organization for standardization of industrial processes. This the US equivalent of the German Institute for Standardization (DIN).

ANSI-Lumen

The American National Standards Institute (ANSI) defines standards and guidelines for various industries, including the audio/video sector.
Units of brightness determined by using a specific measurement procedure, defined by ANSI in 1993.

ANSI-Contrast

A TV's contrast ratio, measured using a test pattern consisting of a checkerboard pattern with eight black and eight white areas. The ANSI contrast indicates how strongly white areas of the picture brighten up neighboring black areas, resulting in lower contrast. Excellent values lie at around 500:1, poor values at around 100:1.

Anti-Aliasing

Anti-Aliasing is used to combat aliasing effects. A filter reduces the level just before the Nyquist Frequency and therefore filters out superfluous frequencies beyond the displayable signal. All picture errors resulting from aliasing effects are therefore eliminated from the outset.

Artifacts

Artifacts are artificial picture errors that are typical of a given technology. They are said to be artificial because they are not present in the original — for example, in a movie — and are instead produced during transmission to the TV. Such errors can occur during signal production, signal storage, or signal playback. In each case, the artifact will occur again and again because of the nature of the system. The exact type of error depends on the technology (analog or digital) and on the type of TV.

The best-known artifacts of analog CRT TVs include 50-Hertz flicker and line flicker. Typical artifacts of digital devices include False Contouring on plasma displays and Block Noise, which results from digital data-reduction.

Aspect ratio

Denotes the ratio of a picture's sides to one another. Expressed either as fractions — 4:3, 16:9, 21:9 — or as decimals — 1.33:1, 1.78:1, 2.35:1 — that give the ratio of the picture's width to the picture's height.

Also see picture format.

AV

Abbreviation of Audio Video. In TV and video technology, the term is used for inputs, outputs, and cables that can simultaneously transmit audio and video signals. The vast majority of remote controls include a button labeled AV. In general, this calls up a list of various AV inputs for the user to choose from — for example, Scart or HDMI.

AC-3

Abbreviation of «Audio Coding 3", used rarely as a synonym for Dolby Digital. Describes the underlying encoding procedure.