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HD Terminology
Prepared by John Bourbonais
4-1-03
- 24P
- Film industry term for twenty-four progressive frames per second. "24P" presently utilized by Panasonic in its "720P" format and Sony in its "1080P" format (see "720P" and "1080P").
- 480P
- Acronym for "480 Progressive Lines." Considered by many to be "entry level HD." Adopted by FOX Television as their High Definition broadcast signal.
- 720P
- Acronym for "720 Progressive Lines." Utilized by the Panasonic Varicam Variable Frame Rate High Definition Camera. Adopted by ESPN HD as their High Definition broadcast signal.
- 1080i
- Acronym for "1080 Interlaced Lines." When utilized by HD cameras, 1080i appears to be ultra high resolution video. The first HD format to gain a market share, 1080i can be found throughout the world of HD sports and has become the HD broadcast signal for CBS and HDNET.
- 1080P
- Acronym for "1080 Progressive Lines." A format developed by Sony to record at 24 frames per second and designed to replace 35mm film.
- Back Focus
- Critical adjustment on located at rear of HD telephoto lens to ensure sharp focus.
- Black Gamma
- A term that describes the tonal reproduction characteristics of a video signal.
- CCD
- A light sensitive semi-conductor used as an image sensor in video cameras.
- Chrominance
- The color information in a television picture. Chrominance can be further broken down into two properties of color: hue and saturation. Also called chroma.
- Clear Scan
- Adjustment within digital cameras to eliminate "screen scroll". Commonly utilized when televisions or computer monitors are within the framing of a shot.
- Composite
- A single video signal containing all of the necessary information to reproduce a color picture.
- Component Video
- Unlike a "Composite Video Signal" which contains all video information in a single signal, a "Component Video Signal" breaks down the video information into three separate signals. Component is often referred to as "R, G, B" for red, green, blue - the three signal carriers.
- Compression Rate
- Ratio to which original video image (Standard Definition or High Definition) is reduced when layed to tape.
- Conform
- Final step in the editing process in which a program is edited to High Definition. Typically follows the "Off-line" process (see "Off-Line").
- Conversions
- Process in which one tape format is duplicated to another tape format. Typical application is after shooting 24P, producer may "convert" 24P" tape to a standard definition format for "Off-line" editing (see "Off-line").
- D5
- Presently the top-of-the line tape format for HD Mastering.
- Depth of Field
- The portion of an image which is in focus.
- Filter
- Although filters such as an "85" had to be applied to the front of the lens for proper color correction of tungten film stocks, video cameras have a "filter wheel" in which proper filtration is applied behind the lens.
- Gain
- Feature on video cameras often utilized to boost overall video level in low-light conditions (see "noise"). Recent video cameras and HD cameras often offer "negative gain" to allow user to open iris thereby decreasing depth-of-field.
- Gamma
- A term that describes the tonal reproduction characteristics of a video signal.
- Grain
- The visible particles (grains) of metallic silver on the film image caused by large clusters of grains on the film emulsion.
- HD-SDI
- Acronym for "High Definition - Serial Digital Interface." A High Definition video signal containing all of the necessary video information to reproduce a color High Definition picture.
- Hue
- Video term referring to the actual color base - red, green, blue and so forth. A common adjustment when preparing video footage for editing.
- Interlaced
- A display technique in which each TV picture, or frame, is produced using two sequential fields. One field contains the off-numbered lines of the frame, and the other the even-numbered lines. The TV tube, or image, is scanned twice, with the lines of two fields interweaved, or interlaced. The technique eliminates visible flicker which can be annoying at low frame rates.
- Knee
- Camera function for dealing with the "highlights" of a video picture. Common user application is to select "Auto Knee" but better results can be achieved through manipulation of the "Knee Menu."
- Luminance
- The brightness information in the television picture. The luminance signal amplitude varies in proportion to the brightness of the televised scene and is therefore capable of producing a complete monochrome picture.
- Neutral Density Filter
- A lens filter that cuts down the intensity of incoming light without altering the color temperature. Typically utilized to decrease the depth-of-field.
- Noise
- Undesirable attribute of video often occurring when video levels are overly boosted or saturated.
- NTSC (National Television Systems Committee)
- A U.S. engineering group that developed a black & white television standard I the early 1940s and a color standard in the early 1040s. Those standards - now called NTSC - are currently used in the United States, Canada and Japan.
- Off-line
- Typically a simplified editing scenario (limited digital effects, limited character generation, simplified audio) offered at a drastically reduced rate. Designed for user to make creative edit decisions without having to pay costs associated with an "On-line" edit system. Standard Definition "Off-line" is a popular way to edit HD. When the editing decisions have been made, one can go to an "On-line" edit system for finishing (see "Conform").
- On-line
- The concluding electronic editing stage in which all editing takes place on a Standard Definition or High Definition finished master.
- PAL
- The European color television system using a 50 cycle power source, 625 scan lines per frame and 25 frames per second.
- Pixel
- Digital sample of the color intensity values of a picture at a given point.
- Progressive
- Attribute of HD Cameras and DVD Players. Each video frame is comprised of a complete picture typically replayed at 24 frames per second.
- Resolution
- The measure of image detail in a television system. Calculated in resolvable lines per picture width and height.
- Saturation
- The variable property of color that is determined by its purity, or its lack of dilution by white light. Highly saturated colors are vivid, while less saturated colors appear pastel.
- Shutter
- Mechanism is a camera that places an opaque surface between the lens and film gate as a new frame of film is being moved into position in the film gate. With video cameras a shutter is produced electronically.
- Standard Definition (SD)
- Standard for color pictures set in the early 1950s. Although the color and resolution of cameras has dramatically increased, the basic principles set decades ago still apply.
- Time Code
- Numerical reference in which each frame of a video picture is assigned a consecutive number.
- White Balance
- The color balancing procedure for a video camera. Allows the camera to ''see'' white under a given lighting condition.
- Zebra Bars
- A camera viewfinder display that places "stripes" over the parts of an image which has reached a pre-determined video level. Usually set at about 100 IRE units and used to assure correct exposure of overall picture.