4:2:2 / 4:2:0 / 4:1:1
Sampling structure in components given on 4 samples.
The first figure indicates the number Y samplings (luminance) on each line.
The second figure indicates the number of Cr and Cb (chrominance) on the odd lines.
The third figure indicates the number of Cr an Cb (chrominance) on the even lines.
AES/EBU
Audio Engineering Society/European Broadcasting Union. Professional digital audio interface standard (usually XLR3).
ANSI
American National Standards Institute. Standard for measuring video projector light intensity, contrast and homogeneity.
BANDWIDTH
Difference between the highest and lowest frequencies of an electronic system, transmitted without distortion or weakness.
BLANKING
Beam deletion
BNC
Coaxial connector with locking features (frequently used in video).
CANDELA/m2
Luminance unit. Ratio between illumination and Pi. Minimum value for movies 30 cd/m2.
CCD
Charge-Coupled Device. Light sensors for electronic devices. Professional cameras are usually equipped with 3 CCDs (one per colour RGB), usually 2/3 inch. CCD chip size is variable.
CHROMINANCE
Colour information in composite video signals (PAL/SECAM/NTSC). Identified by C (Y/C).
COAXIAL
Hardened metal wire cable with an insulated conducting wire for the transfer of electrical signals.
COMPONENT
Codification system of primary colours RGB and 3 other signals Y, R-Y and B-Y with the proportions Y = 0.3R + 0.59 G + 0.11B. This technique has been in application since the beginning of colour television in order to be compatible with black and white. It is used today in the transmission and recording of analog video signals. This colour space is also referred to as YUV.
COMPOSITE
An analog video signal whereby luminance (Y), chrominance (C) and synchronization pulses are joined into one signal.
CONTRAST
Black and white luminance between the dark and the light parts of the image.
CROSS COLOR
Composite video defect appearing as highly saturated coloured spots in areas where the black and white details are processed as colour information.
DFP
Digital Flat Panel. Existed before DVI. It transfers the same type of signals, but only in digital format. Uses different connectors.
DMD (Digital Mirror Device)
Micro-mirror technology (848 x 600, 1024 x 768 and 1280 x 1024) used in DLP (Digital Light Processing) projectors.
DVD (Digital Versatile Disc)
Standard in interactive digital video using MPEG 2 technology.
DVI
Digital Visual Interface. New standard for the digital transmission of graphic computer signals and interactive communication. Its dual connecting system allows for analog transmission.
FLICKER
Instability of the video image at low refresh rates.
FOCUSING
Concentration of a light beam on one spot to obtain a clearly defined image.
FRAME FREQUENCY or Vertical Frequency
It is the second important feature in video or computer equipment. It corresponds to the number of frames scanned per second. The horizontal or vertical frequency is at 50 Hz.
FRAME
The total quantity of lines visible in a complete vertical frequency scan.
GENLOCK
The output of one system is used to synchronize another.
GOP
Group Of Pictures. MPEG 2 handles a group of successive images referred to as a GOP. The most frequently used is GOP12.
GPI
General Purpose Interface defines the interaction between software components, such as a specific video effect.
HAD
Hole Accumulated Diode. Upgraded CCD technology improving the quality of image restitution and solving CCD defects such as vertical smear.
HDSDI
SMPTE292M standard. Digital serial interface. High definition with 1.485Gb/s flow.
HDTV
High Definition Television. This standard records and broadcasts 16:9 images of 1920 dots x 1080 interlaced lines or 720 progressive lines at 50 or 59.94 Hz.
INTERLACE
See interlaced scanning.
INTERLACED SCANNING
A video image produced in two phases or "fields" consisting of even and odd lines. The video image is made of 2 color spaces or frames. 50 frames/second = 25 images/second.
LINE FREQUENCY or Horizontal Frequency
It is the major feature of video or computer equipment: the number of lines generated by a signal in one second. The horizontal or vertical signal is 15,625Hz (15K).
LTC
Linear Time Code. Encodes SMPTE data as audio signal and terminates each frame with a "synch word" in order to synchronize with any video or film content.
LUMEN
Unit of measure to calculate the light flow.
LUMINANCE
Electrical signal producing the gray scales in component and composite video. Carries black and white images. Identified as Y.
LUX
Illumination unit. Ratio between the light flow on the screen surface multiplied by the reflection value of the screen.
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Mb/s
Megabits per second. Digital flow. The average output of a DVD varies between 6 and 10 Mb/s. With non-compressed components the SDI flow is 270 Mb/s.
MPEG (Motion Picture Expert Group)
Sound and image compression standard.
MPEG 1
CD and CD-Rom video compression standard at a maximum output of 1.5 Mb/s and a resolution of 360 dots x 288 lines. VHS quality level.
MPEG 2
DVD compression standard used in today's multimedia players. Standard video output goes up to 15 Mb/s for institutional demands and 50 Mb/s in professional broadcast applications. Resolution is 720 dots x 576 lines. MPEG 2 can also encode an HDTV image with 300 Mb/s output.
NIT
See Candela/m2.
NON-TWISTED
See progressive scanning.
NTSC
National Television System Committee. US coding system of colour images: 525 lines/30 images per second (29.97).
PAL
Phase Alternate Line. European colour coding system at 625 lines/25 images per second.
PIXEL
Picture element. One of many dots that make up the total picture.
PIXEL FREQUENCY
The number of pixels per second, the result of the horizontal frequency and the number of dots per line.
PROGRESSIVE SCANNING
This image reproduction method is non-sequential; the image is generated only once, vertically. Preferred mode for today's computers.
QUADRI-STANDARD
Compatible device with all 4 video standards: SECAM, PAL, NTSC 3.58 and 4.43.
QUANTIFICATION
Amplitude resolution of digital signals in bytes. It is closely related to analog signal dynamics. 16, 20 or 24 audio bytes and 8 or 10 video bytes are current resolutions.
REFRESH RATE
Maximum number of frames displayed on a monitor per second.
RESOLUTION
Sharpness and clarity of an image. The maximum number of pixels possible on a screen calculated in pixels per line.
RGB
Red, Green, Blue, the primary colors. When combined in varying proportions allow for the reproduction of images in color.
RS-422, RS-232, RS-485
Serial data communication standards.
S-VHS
Super VHS offers superior VHS quality with 400-line resolution. It separates the luminance and chrominance signals and reunites them upon reception for better color fidelity.
S-VIDEO
Super video. Transmission of two separate signals: luminance (Y) and chrominance (C).
SAMPLING
Digitalization of a given electrical pulse and translation into a series of 0s and 1s.
SAMPLING FREQUENCY
Number of samples per second. Closely linked to the frequency of the initial analog sampling signal. 44.1Khz for a 20Khz audio frequency. 13.5Mhz for a 6Mhz video frequency.
SCANNING
The act of moving electronic beams in sweeping lines from left to right and from top to bottom and thereby reproducing an image.
SCART
Also known as Euroconnector. 21-pin connector with video RGBS and sound I/O.
SDI
Serial Digital Interface. Standard: SMPTE259M & CCIR601. Digitized video format used for broadcast professional video, relaying both image and sound signals at the same time via a single coaxial cable.
SECAM
Sequential color and memory: the French standard for color TV, 25 images per second.
SMEAR
Smear is an effect created by imperfections of CCD sensor. A bright spot in the image is crossed by a white vertical line.
SMPTE
Society of Motion Picture and Television Engineers. World organization defining standards. Used in defining time codes, but is not the designer of these codes; however when associated refers to the NTSC standard use (29.97 or 30 I/s).
SOFT EDGE BLENDING
Used for multi-video projections and panoramic images. Controls the luminance and the border gamma so as to assure uniform imaging.
SPDIF
Sony-Philips Digital Interface Format. Interface standard for digital audio (RCA optic fiber).
SVGA
Super Video Graphics Array. Resolution at 800 x 600.
SXGA
Super Extended Graphic Array. Resolution at 1280 x 1024.
TALLY
Warning light when the camera is on air.
THROW DISTANCE
Projector positioning charts according to image size.
UXGA
Means Ultra XGA. Resolution at 1600 x 1200.
VECTORSCOPE
Device which measures the chrominance of a composite video signal.
VGA
Video Graphic Array. Resolution at 640 x 480.
WVGA
Video Graphic Array. Resolution at 640 x 480.
WXGA
Video Graphic Array. Resolution at 852 x 480.
VITC
Vertical Interval Time Code. A timing signal that is part of a video recording. Code can be read even in slow motion or freeze frame mode.
XGA
Extended Graphic Array. Resolution at 1024 x 768.
Y/C
See S VIDEO.
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