|1080p||1080 lines of progressive video (1080 lines per frame). Usually refers to 1920 x 1080 resolution in 1.78 aspect ratio.|
With respect to soundtracks, such as those
on movies and DVDs, 5.1 means that the soundtracks are recorded
with five main channels: left, center, right, left surround, and
right surround, plus a low-frequency effects (LFE) bass channel
(called a ".1" channel because it covers only a fraction
of the frequency range of the main channels).
|Aspect Ratio||The width to height ratio of an image . A 4:3 aspect ratio means that the horizontal size is a third again wider than the vertical size. Standard Television ratio is 4:3 or (1.33:1) Widescreen DVD and HDTV aspect ratio is 16x9 (or 1.78:1). Common film aspect ratios are 1.85:1 and 2.35:1 Aspect ratios normalised to a height of 1 are often abbreviated by leaving of the :1.|
|CBR||Constant Bit Rate: Data compressed into a stream with a fixed data rate. The amount of compression (such as quantisation) is varied to match the allocated data rate, but as a result, quality may suffer during high compression periods, In other words the data rate is held constant, while quality is allowed to vary. Compare this to VBR.|
|CCIR-601 BTU||A standard for Digital video. The CCIR changed its name to ITU-R, and the standard is now called ITU-R BT.601|
|Compressionist||The job description of the person that compresses audio or video to remove redundancies in digital data to reduce the amount that must be stored. Lossless compression removes only enough redundancy so that the original data can be recreated exactly as it was. Lossy compression sacrifices additional data to achieve greater compression.|
|DAT||Digital audio tape. A magnetic audio tape format that uses PCM to store digitised audio or digital data.|
|Digital Betacam||Component Digital Metal Video Cassettes generally used as the video input medium for DVD, and uses a 2:1 compression method for standard definition video signals. The Betacam family consist of variants such as SP, SX, and IMX.|
A perceptual coding system for audio , developed by Dolby Laboratories and accepted as an international standard. Dolby Digital is the most common means of encoding audio for DVD-Video and is the mandatory audio compression system for 525/60 (NTSC) discs.
|DTS||Digital Theatre Sound. A perceptual audio-coding system developed for Theatres. A competitor to Dolby Digital and an optional audio track format for DVD-Video and DVD-Audio.|
|DTS-ES||A version of DTS decoding that is compatible with 6.1 channel Dolby surround EX. DTS-ES Discrete is a variation of DTS encoding that carries a discrete rear centre channel instead of a matrixed channel.|
Referred to a Digital Video Disc, and then later as Digital Versatile Disc, the DVD forum then pronounced it as a noun, si it does not stand for anything anymore. It is a a specification for a family of products for storing video/audio and date on 8 cm and 12 cm optical discs.
|Dynamic Range Control||
The differences between the loudest and softest sound in an audio signal. The dynamic range of digital audio is determined by the sample size. Increasing the sample size does not allow louder sounds; it increases the resolution of the signal, thus allowing softer sounds to be separated from the noise floor (and allowing more amplification with less distortion). Therefore the dynamic range refers to the difference between the maximum level of distortion-free signal and the minimum limit reproducible by the equipment.
To transform data for storage or transmission, usually in such a way that redundancies are eliminated or complexity is reduced. Most compression is based upon one or mode encoding methods. Data such as audio or video is encoded for efficient storage and is decoded for access or display.
Frames per second. A measure of the rate at which pictures are shown to create a motion video image. In NTSC and PAL video, each frame is made up of two interlaced fields.
The international standard specifying the format of Digital component Video.
Dolby Digital carries additional information (metadata) that is input during encoding to control audio parameters in a consumer decoder.
Motion Pictures Expert Group. An international committee that developed the MPEG family of audio and video compression systems.
Audio compressed according tho the MPEG perceptual encoding system. MPEG-1 audio provides two channels, which can be in Dolby surround format. MPEG-2 audio adds data to provide discrete multichannel audio. Stereo MPEG audio is one of the two mandatory audio compression systems for 625/50 (PAL) DVD-Video.
video compressed according to the MPEG encoding system. MPEG-1 is typically used for low data rate video such as VideoCD. MPEG-2 is used for higher quality video, especially interlaced videos, such as DVD or HDTV. It is encoded in accordance with the ISO/IEC 13818 specification.
National Television Systems Committee. A committee organised by the Electronics Association (EIA) that developed commercial television broadcast standards for the U.S. The group first established black and white TV standards in 1941, using a scanning system of 525 lines at 60 fields pre second. The second committee standardised colour enhancements using 525 lines at 59.94 fields per second. NTSC refers to the composite colour-encoding systems. The 525/59.94 scanning system (with a 3.58 MHz colour subcarrier) is identified by the letter M and is often incorrectly referred to as NTSC. The NTSC standard is facetiously referred to as meaning never the same colour twice, because of the system’s difficulty in maintaining a colour system.
Phase alternate line. A video standard used in Australia and Europe and other parts of the world for composite colour encoding. Various versions of PAL use different scanning systems and colour sub carrier frequencies (identified with the letters B,D,G,H,I,M, and N) the most common being 625 lines at 50 fields per second, with a colour sub carrier of 4.43 MHz. PAL is also said to mean perfect at last.
Pulse Code Modulation. An uncompressed, digitally coded representation of an analog signal. The waveform is sampled at regular intervals and series of pulses in coded form (usually quantised) are generated to represent the amplitude.
The smallest picture element of an image (one sample of each colour component) A single dot of the array of dots that make up a picture. Sometimes abbreviated to pel. The resolution of a digital display is typically specified in terms of pixels (width by height) and colour depth (the number of bits required to represent each pixel)
A continuous flow of data, usually digitally encoded, designed to be processed sequentially. Also called a bitstream.
A video signal (or component of a video signal) containing information necessary to synchronise the picture horizontally and vertically. Also, specially formulated data on disc, which helps the readout system identify location and specific data structures.
|VBR (Variable Bit Rate)||
Data that can read and processed at a volume that varies over time. A data compression technique that produces a data stream between a fixed minimum and maximum rate. A constant level of compression is generally maintained, with the required band width increasing or decreasing depending on the complexity of the data being encoded. This produces a better quality picture, but can consume more disc storage.
A video image wider that a standard 1.33 (4:3) aspect ratio. When referring to DVD or HDTV, widescreen usually indicates a 1.78 (16:9) aspect ratio.