D-ILA
D1
D2
D3
D5
D9
DAB
DAC
DAT
DATA COMPRESSION
DATA SUPERIMPOSITION
dB
DBS
DC output
DCT
DDC
DDWG
DE-INTERLACING
DECIMATION
DECIMATION FILTER
DECODER
DEFINITION OF A PICTURE
DELAY CORRECTION
DEMULTIPLEXER (DEMUX)
DgKat
DIFFERENTIAL GAIN
DIFFERENTIAL PHASE
DIGITAL DISK RECORDER
DIGITAL-S
DIN
Display Port
DISTORTION
DISTRIBUTION AMPLIFIER
DLP / DMD
DOLBY (Noise Reduction)
DOLBY (Surround/digital)
DOT PITCH
DOUBLE-EDGE ENHANCING
DOWNSTREAM KEYING
Dr, Db
DROP SHADOW
DROPOUT
DTV
DUBBING
DV
DVB
DVC
DVCAM
DVCPRO
DVD
DVE
DVI
D-ILA
Digital Direct Drive Image Light Amplifier. A CMOS chip technology developed by JVC , with 2048X1536 pixels (3.2 megapixel) on a 1.3” chip, used for display devices. The system easily allows HDTV resolutions – up to 1920X1080 to be comfortably displayed. Combining high-speed response and a vertical alignment liquid crystal, this technology enables reproducing clean, smooth and sharp HDTV images.
0

D1
A recording format utilizing a 19 mm-wide (3/4'') video tape and digital component video signals conforming to the ITU-R BT.601-2 (CCIR 601) standard
0

D2
A recording format utilizing a 19 mm-wide (3/4'') video tape and digital composite video signals conforming to the SMPTE 244M standard.
0

D3
A recording format utilizing a 1/2''-wide video tape and digital composite video signals conforming to the SMPTE 244M standard.
0

D5
A recording format utilizing a 1/2''-wide video tape and digital component video signals.
0

D9
Another name for Digital-S, the digital s-Video (YC) format.
0

DAB
Digital Audio Broadcasting. A system recently introduced in Europe and the US, which allows broadcasting of CD quality audio.
0

DAC
(рус. ЦАП)
Digital to Analog Converter. A device doing the opposite of an ADC, converting a digital logic signal to an analog (linear) signal. The ADC and DAC are widely used for conversion between analog and digital video and audio signals.
0

DAT
(рус. ЦАП)
Digital Audio Tape. A system developed for recording and playback of digitized audio signals, while maintaining signal quality as good as with a CD. DV, DVCAM and others are digital video formats. A similar format is used in the computer industry for storage and retrieval of data, mainly for backup purposes.
0

DATA COMPRESSION
A process developed for reducing the number of transmitted or stored bits of information with minimal effect on data or signal quality. Several algorithms (software formulas) as well as specific hardware devices are used for data compression, each with its own drawbacks and advantages. The right system should be selected to suit the specific needs of the user.
0

DATA SUPERIMPOSITION
Use of computer generated red, green and blue data in video applications. Data superimposition over a video signal is carried out by high quality color decoders which convert analog or digital video signals to RGB signals. The computer generated data is genlocked to the video source and superimposed on the decoded RGB signal by using a special key or strobe input. The signal can then be re-encoded to re-establish the original video signal format, now including the computer data (graphics, text, etc.)
0

dB
(рус. дБ)
Decibel. A logarithmic ratio measuring signal amplitude and power, allowing easy evaluation of very large or very small ratios.
0

DBS
(рус. дБ)
Direct Broadcast Satellite. It is also known as DTH - Direct To Home. A satellite transmission system received directly at the consumer’s home.
0

DC output
0

DCT
Discrete Cosine Transform. One of the algorithms (software formulas) used in data compression. This algorithm is widely used in image and movie compression (JPEG and MPEG).
0

DDC
Display Data Channel. A bi-directional communication standard between a graphics source (a PC) and a monitor.
0

DDWG
Digital Display Working Group. A group developing digital display standards such as the DVI.
0

DE-INTERLACING
An electronic procedure that converts two interlaced video fields to a single progressive field. De-interlacing changes the sync rates and the progressive image can be displayed on an appropriate progressive-scan monitor. The de-interlaced image resembles the image of a computer screen, without the interlacing flicker. This is one of the steps used in Scaling.
0

DECIMATION
A digital method for ''eliminating'' redundant pixels in an image. The process is widely used for image scaling and for over-sampled ADCs. If every second pixel is stored in a digital image storage apparatus, the decimation factor is 2, and the image size occupies only one quarter of the original size. Decimation of a high order deteriorates the signal and unwanted artifacts are added to the picture, whether it is a video or a still picture.
0

DECIMATION FILTER
A filter built in decimation circuitry designed to reduce or eliminate the unwanted effects of the decimation process.
0

DECODER
(рус. Декодер)
See Color Decoder.
0

DEFINITION OF A PICTURE
The aggregate of fine details available on the screen. The higher the definition of the picture, the greater the number of fine details that can be recognized on the screen. The fine details of a picture appear in the highest frequency region of the signal. As a result of the limited frequency response of magnetic tapes, of connecting cables and of the electronic circuitry employed in the recording process, the high frequency part of the video spectrum is often attenuated. Therefore, during analog video recording, picture definition is frequently impaired. This creates a loss of fine details and blurs the picture. Each additional generation of a copy of an analog videotape results in fewer and fewer fine details as losses are accumulated. Digital videotapes, due to the nature of digital storage technique, are far less sensitive to this problem. To overcome definition loss, the use of video enhancers is recommended. However, low quality video enhancing, while trying to cure the definition loss problem, generates excessive noise (snow on the screen) and the advantages of enhancing are lost. A high quality image enhancer uses a noise gate to limit the snow and noise and produces a sharp image with minimal snow.
0

DELAY CORRECTION
When an electronic signal travels through electronic circuitry or through a coaxial cable, delay problems may occur. The result of the delay in video is usually a blurred (ghostly, shadowed) image and special electronic circuitry is needed to correct it. Delay correction functions are found on all better video processing equipment. A common problem in analog video is the difference of delay between the luminance and the chrominance channels of the image, resulting in colors that look wrong or mis-registered.
0

DEMULTIPLEXER (DEMUX)
An electronic device for separating several signals, which were combined by a device called a multiplexer. In digital-signals, de-multiplexers separate digital video from digital audio, which were combined by time division multiplexing (TDM).
0

DgKat
0

DIFFERENTIAL GAIN
A measure of non-linearity related to a composite video amplifier/processor. It is measured by comparing two chrominance signals of initially equal amplitudes riding on two different luminance levels. The inaccuracy is measured as a percentage.
0

DIFFERENTIAL PHASE
A measure of non-linearity related to a composite video amplifier/processor. It is measured by comparing two chrominance signals of initially equal phases riding on two different luminance levels. The inaccuracy is measured in degrees.
0

DIGITAL DISK RECORDER
A relatively new system, initially intended for post-production purposes, for recording video and audio on a digital disk (such as a computer hard drive or a recordable DVD). The system was adapted to video camera capturing as well – as for ENG and production - using digital media for recording digital video. Solid state digital media is used for those purposes as well. The system was further developed for consumer use – as in set-top boxes for instant TV program recording and playback. The advantages of this system for editing purposes are extremely fast access to any point on the disk, elimination of dropout and very fast back and forth shuttle speed. Several digital formats of data storage exist. Digital video editing using this media is sometimes called Non-Linear editing (non-analog).
0

DIGITAL-S
A digital video format introduced by JVC™. This format is “back” compatible with the S-VHS format so cassettes recorded in S-VHS can be used with a DIGITAL-S VCR. The technical specifications are very similar to the DVCPRO format - 4:2:2 encoding, 3.3:1 DCT compression and a 50 Mbits/sec data rate. The cassette lasts for 104 minutes and is 0.5 inches wide.
0

DIN
Deutsche Industrie Norme. A German based standardization system, adopted by other countries as well. The DIN standard connectors for example, are very popular on video and audio equipment.
0

Display Port
0

DISTORTION
In audio, this term implies undesirable changes in the waveform of a signal caused by the introduction of spurious elements. When a pure sine signal is fed into an amplifier and comes out harmonized, additional tones are created, naturally related to the original tone. This upsets the relationship between a specific tone and other tones related to it. In audio there are several distortion patterns - harmonic distortion, crossover distortion, transient distortion and intermodulation distortion. No matter what the type is, the result is unpleasant to the ear. Video distortion, like audio distortion, is the result of improper signal handling during video amplifying and processing. Video signal distortion affects the luminance or chrominance portions of the signal. It may distort the picture and produce improper contrast, faulty luminance levels, twisted images, erroneous colors and snow. The goal of a good video processor, is, as in audio, to be a ''wire with amplification'' device which does not unnecessarily affect the brightness, contrast and tonal quality of the image.
0

DISTRIBUTION AMPLIFIER
A device which distributes one video, audio, graphics or digital signal source to several acceptors for simultaneous recording, monitoring or processing. A good quality distribution amplifier amplifies the incoming signal, pre-compensates the signal for potential losses (resulting fr om the use of long cables, for example) and generates several identical buffered and amplified outputs. Video distribution amplifiers are mainly used in duplication studios wh ere many copies of a tape must be simultaneously generated from one source. Often, a video processor is inserted between the source and the distribution amplifier for correction and fine-tuning of the source signal before multiplication, so that all copies are corrected in the same way.
0

DLP / DMD
Digital Light Processing. A graphics/video projector part, based on DMD (Digital Micromirror Device) - a chip developed by Texas Instruments. The microchip has thousands of micromirrors on its face, reflecting light emitted on it. The mirror’s angle dictates the amount of the reflected light. Projectors using this technology output a high contrast image.
0

DOLBY (Noise Reduction)
A technique developed by Dolby™ Laboratories which improves the signal-to-noise ratio of a recording by raising the level of specific frequencies in quiet passages before recording, and lowering them to their original levels during playback (a compression- expansion process). This automatically reduces any noise that was introduced as a result of the recording or playback process. There are several schemes related to DOLBY noise reduction, using different frequency bands of operation.
0

DOLBY (Surround/digital)
An analog/digital transmitted audio system developed by Dolby™ Laboratories for encoding audio surround channels within a videocassette / DVD / TV transmission mainly for home or cinema theatre use. The analog system adds three additional channels - center and delayed back right and left. The digital AC-3 system have the surround channels separated and digitally encoded. In both cases a special decoder is needed to retrieve the additional audio channels.
0

DOT PITCH
The distance between the pixels on a monitor, measured in millimeters. The smaller the pitch, the higher is the apparent screen resolution.
0

DOUBLE-EDGE ENHANCING
See Enhancing.
0

DOWNSTREAM KEYING
One of the special effects employed by a special effects generator. A video picture is painted with natural or with artificial colors produced by the special effects generator as a function of its brightness. A washed-out sky can be painted a brilliant red, for example. Colors are streamed down from brightest to darkest and any level of brightness can be changed down to any darker level.
0

Dr, Db
Color difference related signals for the SECAM system color modulation.
0

DROP SHADOW
A special effect, which adds an artificial shadow or a three-dimensional, extruded shadow to a scene or an inserted object. This effect is used also in titling in order to emphasize the inserted titles.
0

DROPOUT
Partial loss of a video picture, usually seen on the screen as white streaks, resulting in a poor quality playback. Flaws in magnetic tape coating resulting in loss of magnetic particles from the tape are the main cause of dropout. Special electronic equipment, usually digital, called dropout compensators, is needed to eliminate dropout effects. Normally, a dropout compensator replaces the missing information with data from adjacent pixels, lines or fields.
0

DTV
Digital Television. The proposed standard for digital video broadcasting in the US and Canada. The system is based on MPEG-2 and is similar to the DVB system in most respects.
0

DUBBING
See Audio Dub.
0

DV
Digital Video. A format initially used by SONY™ for the output of a digital camera or VCR. The DV format uses a special communication protocol: IEEE1394 (a.k.a. Firewire, iLink). The format is basically a digital component video format (YUV). In PAL it is based on 50 fields/sec and 625 lines per frame and the encoding system is 4:2:0. In NTSC there are 60 fields/sec and 525 lines and the encoding system is 4:1:1. These field and line rates are similar to those used in the analog formats. The audio part of the DV format is digitally encoded but uncompressed, with sampling rates that can be selected by the user: 44.1 kHz @16bits for two sound channels (similar to an audio CD) or @ 12 bit and 32 kHz sampling rate, for four audio channels. The compression rate is about 5:1 and this standard provides a 25Mbit/sec data rate. Every compressed frame is fed in parallel to ten channels during recording (NTSC) or to 12 channels (PAL), therefore, dropout effects become almost obsolete. There are two cassette sizes for this format: a mini cassette for up to 60 minutes of recording and a regular cassette for up to 240 minutes of recording.
0

DVB
Digital Video Broadcast. The system proposed for digital video broadcast in Europe and is similar to analog TV broadcast. The system is based on satellite transmission, ground-based receivers and the video signal is MPEG-2 encoded.
0

DVC
Digital Video Cassette. A domestic and professional cassette format. DVC cassettes come in two sizes - mini or regular-sized for camera or desktop VCR use. The mini cassette (6.35mm) can be played directly from the desktop VCR without using adapters. Sometimes, the mini cassettes have a memory chip built-in. Resolutions of up to 500 lines are achievable.
0

DVCAM
A digital video format introduced by SONY™. This format uses DV-like cassettes, has a 4:1:1 encoding scheme and outputs a 25Mbits/sec data rate. Cassettes come in two sizes- 46 minutes for field use and 180 minutes for desktop VCRs.
0

DVCPRO
A digital component video format introduced by Panasonic™ and Philips BTS™. The format uses two cassette sizes- 6.35mm and 0.5 inch. It provides a stream of digital information @ 25 Mbits/sec and has two uncompressed audio channels. It operated initially at 4:1:1 encoding and 5:1 DCT compression, but was recently re-introduced at 4:2:2 encoding and a lower, 3:3:1 rate of compression. This has changed the amount of time that can be recorded on tape from 123 minutes for the desktop DVCPRO VCR operating at 4:1:1 to 61.5 minutes at 4:2:2.
0

DVD
Digital Versatile Disk (formerly: Digital Video Disk). A data or video media, allowing storage of data or playback of video and audio from a digitally recorded disk which resembles a CD. The video disk allows playback of a full feature movie of more than 2 hours. MPEG compression is used for recording. The audio section is digitally recorded as well, with various surround sound schemes, such as Dolby AC3. The world was divided into several “zones” incompatible with each other. Several different standards exist, similar to PAL and NTSC and some manufacturers have released Multi-standard / Multi-zone players. Copy protection schemes are built into the DVD player in order to avoid piracy. The single layer DVD capacity is about 4.7 gigabytes and the double layer capacity is 8.5 gigabytes. DVD players are available for the PC as well, which also allow playback of regular data CD-ROMs as well as music CDs. Recordable DVD (named DVD RAM or DVD R) has recently been introduced. There are currently 5 leading standards for recordable DVDs. The old one which was recently upgraded, is the DVD RAM, and then there are DVD+R, DVD+RW (Rewritable) DVD-R and DVD-RW (Rewritable). It will take several years until one standard prevails, if at all. In a DVD, as the signals are recorded digitally, quality is expected to be very high, and fast, random access to any part of a movie will allow fast and easy editing. There are already stand-alone DVD recorders in the market with analog or digital inputs, allowing the recording of up to 2 hours of high quality video or TV programs, or several hours of lower video quality. The recordable DVD probably marks the end of the classic VCR.
0

DVE
Digital Video Effects. Special effects generators which employ digital signal processing to create two or three dimensional digital wipe effects, where for example, the image can be rolled out of the screen, broken into tiny pieces or converted into a tube-like picture.
0

DVI
Digital Visual Interface. A digital graphics interface standard, using a large type of graphics connector. The RGB signals are transferred differentially and digitally, differing from the VGA analog standard. This standard is used for interfacing between graphics sources such as a PC, grabber card, set top box etc, and a graphics acceptors such as a digital monitor, Plasma screen, video/data projector and similar devices. Control data is also transferred via the DVI interface. The DVI-D connector (24 pins) uses only the digital format, while the DVI-I connector (29 pins) transfers digital and “old” analog VGA type signals on additional pins. The DVI signals - due to their high-speed digital contents - are sensitive to cable length, and are prone to digital problems like the Cliff-effect and jitter, similar to the DV or SDI signals.
0

Логин:
Пароль:
Контакты | ISO | Гарантия | Обработка персональных данных
Copyright © Kramer Electronics LTD. 1981—2017.
Yandex.Metrica