Electronic Cinematography

1080I - 1080 line, 1920 pixel, wide screen 16:9 aspect ratio, 30 frames per second format which is interlace scanned.

1080P - 1080 line, 1920 pixel, wide screen 16:9 aspect ratio, 30 frames per second format which is progressively scanned.

1940P - 1940 line, 4096 pixel, wide screen 16:9 aspect ratio, 30 frames per second format which is interlace scanned.

4:2:2 - A commonly used term for a component digital video format. The details of the format are specified in the ITU-R 601 standard. The numerals 4:2:2 denote the ratio of the sampling rates of the single luminance channel to the two color difference channels. For every four luminance samples there are two samples of each color difference channel.

480P - 480 line, 704 pixel, wide screen 1 6:9 or 4:3 aspect ratio format 3 which are progressively scanned. Frame rates are 24, 30 or 60 frames per second.

5.1 SURROUND SOUND - Surround sound audio system that includes five full bandwidth channels (left front, right front, center dialog, left rear surround, right rear surround) and one channel of limited bandwidth for use as a bass extend. Dolby AC-3 is an example of an encoded (compressed) 5.1 audio system.

56 Kilobit Leased Line - A 56 kilobit (56,000 bits per second) leased line is currently the smallest bandwidth transmission data circuit useful in Internet applications. It is also roughly the bandwidth needed for a voice phone call and will be the new speed of high end modems.

720P - 720 line, 1 280 pixel, wide screen 1 6:9 aspect ratio format which is progressively scanned. Frame rates are 24, 30 or 60 frames per second.

A DIGITAL WATERMARK - A technique to protect intellectual property. Bits are spread throughout an image that cannot be seen by the naked eye, but can be read by a computer to identify the rightsholder.

AC-3 - AC-3 is Dolby's trademark for digital sound system with either 2 or 5.1 channels. AC-3 multi-channel sound provides five completely discrete channels: Left, Center, Right, Left Rear, Right Rear & subwoofer. The nominal digital bit rate is 384 kilobits per second.

AES / EBU - The informal name for a digital audio standard (AES3) established jointly by the Audio Engineering Society and European Broadcast Union organization.

ALIAS - A form of nonlinear distortion associated with signal sampling. If samples are taken often enough, the digital signal will be a faithful reproduction of the analog signal. To achieve this, the sampling frequency must be a least twice the highest frequency found in the analog signal being sampled. This minimum sampling frequency is often called the Nyquist frequency.

ALIASING - Defects in a TV picture typically caused when the original signal is sampled at too low a rate by sampling at a frequency below the Nyquist limit. Poor filtering of digital video produce these spurious waveforms. These erroneous signals or artifacts are typically seen as jagged steps on diagonal lines and twinkling or brightening of the picture detail.

ANALOG (SIGNAL) - An adjective describing any signal that varies continuously as opposed to a digital signal that contains discrete levels representing the binary digits 0 and 1.

ANCILLARY DATA - Data not related to the picture content that is imbedded in the data stream of a digital video signal. Ancillary data is commonly used to transport digital audio, timecode or other picture related auxiliary data.

ANTI-ALIASING - A filtering process to prevent aliasing or to reduce the aliasing that is already in the signal i.e. the pre-filtering or post filtering of any data to ensure that they are suitable for the particular sampling structure being used. For instance, smoothing out diagonal lines or curved surfaces in a digitally generated wipe pattern or text from a character generator are particular cases of anti-allasing. With reference to images it commonly means prevention of jaggies. Removal of the same artifacts after sampling is usually more difficult and normally involves greater softening of the image.

Aperture - The aperture is the rectangular size of the imaged area on the imaging device.

APERTURE CORRECTION - Horizontal, vertical or two-dimensional processing of video signal with purpose of correcting frequency response distortions to enhance the sharpness of the picture.

ASA or ISO - The result of all the transfer times, the effect of a shutter, if any, and any other issues that can be combined to express the effective sensitivity of the imaging device. Even though ASA is typically a term reserved for film, it is appropriate here as well.

ASPECT RATIO - The ratio of television picture width to height.

ASPECT RATIO CONVERSION - Conversion of the T\t picture geometry preserving the scanning format. Note that the video signal itself is aspect ratio independent. A ITU-R BT601 signal may be either 4:3 or 1 6:9. Only the display screen has an aspect ratio, thus a 1 6:9 signal will appear anamorphic on a 4:3 display.

ASSET - Any media product that has potential value in any format.

ASYNCNRONOUS - Any transmission technique that does not require a common clock between two communicating devices, but instead derives timing signals from special bits or characters imbedded the data stream itself.

BACKGROUND - When used in the discussion of composite photography, the Background is the component of the image that is the opposite of foreground. This would include any non-primary elements such as scenery, walls, crowds of people, etc.

BANDWIDTH - Bandwidth is the amount of data, measured usually in bits per second, that can be sent through a dedicated (leased) transmission circuit.

BANDWIDTH - The amount of frequency or data rate required to transmit or store information. Bandwidth is measured in Hertz (Hz) or bits per second (baud) Video signals require more bandwidth than either audio or computer data.

BASEBAND - Any signal in its original form prior to modulation or after demodulation.

BIT - A bit is the primary unit of digital data. Written in binary language as a "1" or a "0".

BYTE - A byte is composed of 8 bits.

CCD - Charged Coupled Device - The charged-coupled device is assumed to be the imaging device of choice for use in an all solid-state camera.

CCIR - International Radio Consultative Committee, an international standards committee no longer in operation and replaced by the International Telecommunications Union (ITU).

CGI (Computer Generated Imagery) - An image that is synthetic and can appear to be either graphic or photo-realistic in nature. A CGI image is one that originates in the computer.

CHROMINANCE - The color portion of a video signal carrying the information about color hue and saturation, but not its luminance or brightness. In component systems the R-Y, B-Y or Cr,Cb signals carry the chrominance information.

CINEMATOGRAPHER - The person that determines the exact nature of the lighting, camera placement, exposure and movement that is performed during the filming of live or motion controled photographic elements in a media project.

CLOCK JITTER - Timing uncertainty of the data cell edges in a digital signal.

CLOCK RECOVERY - The reconstruction of timing information from digital data.

CNANNEL CODING - Describes the way in which the Is and Os of the data stream are represented on the transmission path.

CODEC (Coder -Decoder) - A device that converts analog video and audio signals into a digital format for transmission over telecommunications facilities and also converts received digital signals back into analog format.

CODING - Representing an information signal as a series of numbers, usually in binary form.

COLOR ENCODING - In broadcast television, the transformation of primary color signals (or luminance and color difference signals) into composite video.

COMB FILTER - Device using the periodic repetition of chrominance subcarrier phases along the vertical axis and sometimes the temporal axis to perform luminance-chrominance separation in the decoder. In the signal frequency domain, its response has a periodic (comb-like) shape.

COMPONENT DIGITAL - A digital representation of a component analog signal set, most often Y, B-Y, R-Y. The encoding parameters are specified by ITU-R BT601.5

COMPONENT VIDEO - Set of primary color signals, RGB, or any set of signals produced by reversible matrixing of these signals such as Y, Cr, Cb.

COMPOSITE VIDEO - A composite video signal is one in which the luminance and chrominance are combined with synchronization signals using an interleaving encoding standard such as NTSC, PAL, or SECAM.

Composited or Composite - A term used to describe the act of combining foreground and background image information. A composite also would describe any combination of multiple image elements to create a single image. Bluescreen is a composite technique.

COMPOUND ASSET - A media product comprised of more than one element. A shot form a film contains video, audio, musical and sometimes computer-generated materials and elements.

COMPRESSION ARTIFACTS - Compacting of a digital signal, particularly when a high compression ratio is used, may result in small errors when the signal is decompressed. These unwanted defects are known as artifacts. Artifacts may resemble noise or edge busyness or may cause parts of the picture particularly fast moving portions to be displayed with the movement distorted or missing.

CONTRIBUTION QUALITY - Describes a level of encoding or compression for use in a production environment. Contribution quality has the following attributes: short latency, multiple generations with minimal degradation, transparent concatenation with distribution level compression encoding. MPEC 2@ 4:2:2 is an example of contribution quality compression.

COVERAGE - During the process of photographing a scene for a media program, coverage is a term given to the acquisition of photographed scenes other than the master scene. This would include close-ups, over the shoulder, extreme wide shots or reaction shots. Coverage is often not photographed at the same length as the original master scene being covered.

CROSS-COLOR - Picture degradation resulting from the color modulation scheme used to create composite analog television. Cross-color artifacts result when the luminance signal contains frequencies near the subcarrier frequency resulting in spurious color.

CROSS-LUMINANCE - Picture degradation resulting from the color modulation scheme used to create composite analog television. Cross-luminance artifacts are caused by a change of the luminance phase from field to field near edges of objects in a scene due to imperfect cancellation of the subcarrier.

D1 VIDEO - An component digital video recording format that uses data conforming to the ITU-R BT601 standard. Uses a cassette containing 19mm wide tape. (Often used incorrectly to indicate component digital video.)

D2 VIDEO - A composite digital video recording format that uses data conforming to SMPTE standard 244M. Uses a cassette containing 19mm wide tape. (Often used incorrectly to indicate composite digital video.)

D3 VIDEO - A composite digital video recording format that uses data conforming to SMPTE standard 244M. Uses a cassette containing 1/2" wide magnetic tape.

D5 VIDEO - A component digital video recording format that uses data conforming to the ITU-R BT601 standard. Uses a cassette containing 1/2' wide magnetic tape. Can use mezzanine level compression to record 720P and 1 0801 signals.

DAM (Digital Asset Management) - DAM is the cataloging and storing material on a digital system in such a way that authorized people can search, locate and retrieve, manipulate and return all or part of the contents. In an entertainment company, the system must accommodate text, drawings, 2D and 3D models, photographs and high-quality video and audio.

DCT (Discrete Cosine Transform) - A mathematical process similar to Fourier transform, that converts time domain information into frequency domain information. As a digital signal processing algorithm DCT is used by MPEG encoders to convert image information to the spatial frequency domain where the image data can be efficiently quantized and compressed.

DCT TAPE FORMAT - A component digital video recording format that uses data conforming to the ITU-R BT601 standard. Uses a cassette containing 19mm wide magnetic tape. Makes use of 2:1 video compression. Manufactured by Ampex.

DECIMATION - A simple variant of down-sampling achieved by discarding information for instance by using only every other sample of video data. Decimation can bring aliasing problems if not accompanied by appropriate pre-filtering.

DECODING (Composite to Component) - The process that separates an analog video signal that has encoded chrominance information interleaved with luminance information into individual luminance and chrominance signals.

DEFOCUS - Optical or digital effect where the whole frame of video or some part of it appears to be significantly blurred. For instance, a single white pixel will spread gradually over several of its neighbors. Similar to, but, not the same as anti-aliasing.

DE-INTERLACING - The process that converts an interlaced scanned image to a progressive scanned image.

DEMULTIPLEX - The separation of two or more signals that were previously combined by a compatible multiplexer and transmitted over a single channel.

DEVELOPMENT - In the entertainment industry, development usually refers to the act of creating and refining a story idea to make it ready to produce. The development process often additionally refers to the casting of major talent for the production including the Director, Talent and even some "below the line" talent such as key crew members.

Digital Asset - Any digitally encoded media product that has potential value in any format.

DIGITAL FINGERPRINT - A security record that tells who entered the asset management system, how long they were there and what files they accessed.

Digital Negative - A term used to describe a string of digital words, bytes and files that describe the necessary components to reproduce a media image. The digital negative then becomes the master storage medium for the program material including all components such as sound and image.

DISTRIBUTION QUALITY - A level of compression/encoding designed to be delivered to the final signal destination or display, usually in a consumer environment. MPEC2 @ ML is an example of distribution quality compression.

DITHER - A random, low-level signal (often white noise) added to an analog signal prior to sampling to help linearize quantizing steps.

DOT CRAWL - Picture degradation resulting from the color modulation scheme used to create composite analog television. Cross-luminance artifacts are caused by a change of the luminance phase from field to field near edges of objects in a scene due to imperfect cancellation of the subcarrier.

DOWN CONVERSION - Standards conversion where the line rate of the output is significantly lower than that of the input. End of active video in component digital systems. A timing reference signal that indicates the active picture area of a video line has ended.

E-1 CIRCUIT - An E-1 Circuit (2,000,000 bits per second) is the European equivalent (roughly speaking) of a T-1.

EAU (European Broadcast Union) - An organization of European broadcasters.

EDH (Error Detection and Handling) - SMPTE RP-165 for recognizing errors in the serial digital signal.

EITHERNET - Ethernet is a local area network transport protocol that is one of the most pervasive in the networking industry. It offers a 10 megabit (10,000,000 bits per second) speed for data throughput.

ELEMENTARY STREAM (MPEG) - A coded MPEG bitstream for one program of audio or video or one data stream.

EMBEDDED AUDIO - Method of transmitting a digital video signal together with accompanying (multi-channel) sound by way of insertion of audio data packets into the ancillary data capacity of the serial digital video stream. (SMPTE standard 272M).

ENCRYPTION - Encoding a digital asset so that the receiver must have a decoder or security "key" in order to view the material. Cable networks encrypt their signals and local cable operators enable viewers' set-top boxes to decode the signal.

ERROR CONCEALMENT - A technique used when error correction fails. Erroneous data is replaced by data synthesized from surrounding pixels.

ERROR CORRECTION - A scheme that adds overhead to the data to permit a certain level of errors to be detected and corrected.

Extraction Screen -

EYE PATTERN - A digital wave form that can be used to evaluate channel performance.

FIELD SEGMENTATION - The process of splitting a progressive image frame into two parts (fields) that are then transported and manipulated as two fields of one frame.

FILM MODE - Mode of vertical-temporal video signal processing which assumes that odd and even fields of the TV frame contain information from the same time moment, typical of film.

First Unit - The group or crew that performs the acquisition of the primary elements of a media program. A first unit is minimally comprised of the principal actors, director and producers. First unit is also the first production unit that is assembled to photograph scenes to be used in a movie or television program.

FIVE-FIELD SEQUENCE - The relationship between the field rate of NTSC video when synchronized with the 48kHz sampling rate of audio which results in a whole number of audio samples that can only exist in multiples of five fields.

Foreground - The foreground is the portion of a media image that is usually the principal element as compared to the background elements. An actor standing in a room would be considered the foreground while the room would be considered the background. In composite photography, the foreground element would be typically shot on some kind of extraction screen, bluescreen or greenscreen, with the intent that the image be combined or composited with its associated background at another time.

FORMAT CONVERSION - The process of both encoding/decoding and resampling of digital rates.

FRAME RATE CONVERSION - The process of converting video signals from one frame rate to another, usually preserving the number of lines per frame.

Green light - During the process of development of a media program or event, the Green Light point is the point where the funding agent or studio, in most cases, commits to the availability of funds and gives the official "go-ahead" to the production company to commence First Unit photography.

Green Lit - A movie, television show that is proceeding with its production plan after official approval from it funding agent or studio.

Green Screen or Blue Screen - A colored wall panel that is used behind a photographed element that will later be replaced with another photographed or generated scene element. The term(s) are often used to describe the act of photographing the foreground element for a to-be composited image. Green and blue are the most common colors used in this process but any color can be potentially used. A more accurate term would be "extraction screen" if a specific color background screen is not required or has not been committed to.

HANGING DOTS - Cross-luminance near sharp saturated horizontal colored edges.

IMPULSE NOISE - Artifact of video signal transmission. It may be suppressed by median filtering. "Sparklies" is the term for the specific form of impulse noise typical of marginal satellite reception.

In the can - When an element of a media program, movie or television show has been recorded or photographed, we say that it is "In the Can". Historically, it would refer to the act of placing exposed motion picture film back in its can so that it can be sent to the laboratory for developing.

INTERLACE - A video scanning system where the odd and even numbered lines of an image are captured and transmitted separately in time, as two interlaced fields, in order to achieve a 2:1 analog bandwidth reduction. Approximately 2/3 the vertical resolution of a like dimensioned progressive system.


INTERPOLATION - In digital video, the creation of new pixels in the image by some method of mathematically manipulating the values of neighboring pixels. Interpolation involves using existing sampled data points to predict values between these points. The simplest form of interpolation is to connect these data points with straight lines ( a two-tap linear interpolation filter). It is used in digital video system for picture size changes and other manipulations including standards conversion.

ISP (Internet Service Provider) - A company that provides commercial and comsumer access to the internet through dial-up and leased line access.

ITU (International Telecommunications Union) - An international broadcast standards committee that replaced the CCIR.

ITU-R BT.601.5 - Formerly known as CCIR 601. An international standard for component digital television from which was derived the SMPTE 125M standard. This ITU recommendation defines the sampling systems, matrix values and filter characteristics for both Y, B-Y, R-Y and RCB component digital television.

JAGGIES - Jargon for spatial aliasing that appears as jagged steps on diagonal lines in a TV picture. Caused by insufficient filtering, violation of the Nyquist limit and/or poor interpolation. See "Aliasing".

JITTER - Instantaneous random timing errors in a desired signal.

LATENCY - The time it takes a signal or bit stream to get through a given process such as a compression/decompression cycle or the delay in data access due to disk rotation.

Lens Format - In describing the lens necessary to image on any sensing device, or a solid-state aperture, use common film formats. This will include the following: (a) Hasselblad ( 2 1/4 by 2 1/4 inch square ), (b) 35mm Still ( Nikon style ), (c) 35mm Motion Picture ( Such as PL and/or Panavision mount lenses )

LINE DOUBLING - Simplified variant of line rate up conversion where every other line of the output signal is merely a copy of the previous one, usually for display purposes to reduce the visibility of line structure and interline flicker.

LUMINANCE - The monochrome (black and white) component of a color television signal.

METADATA - Data describing other data or information about the asset. Metadata can include but is not limited to, information about how the asset was acquired, who holds the rights to it, pointers to the related contracts, its location, format and descriptions of its contents.

MEZZANINE LEVEL COMPRESSION - Compression system that provides contribution quality.

MOIRE' - A wavy unwanted pattern, that is usually caused by interference or too low a sampling rate. A cross-color moire' pattern is colored even if the source picture is not - this may be caused by the beating of the luminance frequencies generated by say a tweed jacket and the color subcarrier frequency.

MOTION ADAPTIVE - A design that senses motion in order to alter the way it functions, for the purpose of avoiding or reducing some motion related artifacts.

MOTION BLUR - An effect caused by integration or the image being composed from a sum of the latest image plus a smaller portion of the previous sum and so on. The result is that moving objects leave a trail behind them giving rise to a blurred appearance. Such an artifact is normally associated with 2 field standards conversion or tube cameras. As a digital video effect, the above artifact may be generated deliberately. Motion blur is an usually considered a desirable artifact that is most inherent in motion picture photography where the camera shutter is open for a period of 1/48 of a second and objects in the image continue to move during that period.

MOTION COMPENSATION - Image processing system that uses motion detection, estimation and adaptation in order to produce smoother temporal image sequences. Typically used in standards conversion and video compression.

MOTION DETECTION - Operation of video signal processing aimed to produce an output indicating the pixels or groups of pixels which belong to moving objects as opposed to static portions of the picture.

MOTION ESTIMATION - Operation of video signal processing designed to produce a motion vector signal.

MOTION VECTOR - A two-component video signal showing the magnitude and direction of moving object displacement over given time interval, e.g. during one T\/ field. Usually represented in Cartesian coordinates, but, could equally well be represented in polar notation.

MPEG (Motion Pictures Expert Group) - An international group of industry experts set up to standardize compressed moving pictures and audio.

MULTIPLEX - A technique for putting two or more signals into a single channel.

MULTIPLEXER - Device for combining two or more signals, electrical or optical, into a single signal.

NATIVE FORMAT - For image capture and post production native format means the original sampling format of the material. For image display devices, native format means the display scanning format that all material is converted to prior to presentation.

NOISE - In a cable or circuit, any extraneous signal which tends to interfere with the signal normally present in or passing through the system.

NOMINAL VIEWING DISTANCE - Distance between viewer and TV picture at which the TV raster line structure becomes invisible. For 525 line systems, the recommended viewing distance is from 5 to 7 times screen height.

NONLINEARITY - Having gain vary as a function of signal amplitude.

NYOUIST SAMPLING THEOREM - Intervals between successive sample must be equal to or less than one-half the period of the highest frequency.

NYQUIST FREQUENCY - The Nyquist rate is considered the minimum sampling frequency for correct digital reproduction of a given signal or twice the signal bandwidth. Alternatively, the Nyquist frequency is the highest signal frequency which can be correctly reproduced for a given sampling rate.

OC-3 - An OC-3 circuit (155,000,000 bits per second) is the nominal backbone speed that major national ISPs use in the United States.

OC-48 - An OC-48 circuit (2,400,000,000 bits or 2.4 gigabits per-second) is the typical speed for many aggregated telephone voice circuits on inter city fiber optic lines.

ORTHAGONAL SAMPLING - A sampling method done in phase with the horizontal line such that sample positions are aligned vertically in the image.

OVERSAMPLING - Use of a higher than necessary sampling rate in converters to simplify analog filtering.

OVERSCAN - Displaying less than the complete area of a TV picture image to a viewer. All CRT based TV sets are overscanned by a few percent.

PAN AND SCAN - Aspect ratio conversion from wide to narrow format with full vertical screen occupation and online control of horizontal centering.

PES (Packetized Elementary Stream) - A coded MPEG bitstream for one program of audio or video or one data stream. PES includes stamps and header information.

Photo-realistic - A live action image would be considered photo-realistic. Usually the term is reserved to the creation of a computer generated image (CGI) that is created with the details and quality that it would appear to be an actual photo.

Pixel - The pixel is the smallest division or element that a single image will be divided. In our discussions, we assume square pixels. With square pixels, we can easily discuss the effects of pixel resolution on aspect ration.

Pixel Depth - Pixel Depth is the number of bits that each pixel can represent. This will be discussed as a linear, two's complement manner.

Post Production - At the point where the First Unit has completed live action work on a media program, movie or television program, and the work to be done consists of non-realtime activities such as editing, sound mixing, compositing, image manipulation, image creation, or any alteration of the media product that leads to the final product a production process is said to be in Post Production.

Post Rendering - Post Rendering is

Pre-Production - Pre-Production is used to describe the work that is done prior to the commencement of First Unit photography in a movie or television show. There is no absolute relationship between a media program, movie or television program being "green lit" and the act of pre-production. Typically, the tasks undertaken during pre-production include the planning of specific jobs that must be done to create the media program.

Preview - A Preview is any act of looking at a media element prior to its being committed to its final form. We preview composite images in a rough form prior to committing the full effort to completing the composite as a manner of determining that the final composite will contain the necessary elements to create the desired scene. We preview entire scenes when we view them in front of people that are not the final target audience. Previews are use to judge and grade images or scenes at a point in time where they can be modified before they are committed to their final form.

Pre-visualization - Pre-visualization is a term used to describe the process of actually looking at a representative image to be used in a media program, television program or movie. A pre-visualization may include stand-in actors, computer generated elements that are planned to be photographed live, or live photographed images that are planned to be computer generated. Pre-visualization is typically performed at at a point in time where experimenting with the images is more cost effective than the actual manner in which an image would be committed to a media.

QUANTIZATION - The process of converting a continuous analog input into a set of discrete output steps called quantizing levels.

QUANTIZING NOISE - The deviation of a signal from its original or correct value which results from the quantization process. In serial digital, a granular type of noise only present in the presence of a signal.

RATE CONVERSION - The process of converting from one sample rate to another. The digital sample rate for the component format is 13.5 MHz. For the composite format it is either 14.3 MHz for NTSC or 17.7 MHz for PAL. Often used incorrectly to indicate both resampling of digital rates and encoding/decoding.

Real-time - Any production act that is done in a linear form from start to finish. This would include short segments as well as longer segments. If frames of a media program are created or processed in the frame rate that is the designed final frame rate, that act is considered to be real-time.

RECLOCKING - The process of clocking the data with a regenerated clock.

RESOLUTION - The measure of the ability of a television system to reproduce detail. Related directly to system bandwidth. The number of bits determines the resolution of the digital signal. Eight bits is the minimum acceptable for broadcast television. Start of active video in component digital systems. The timing reference that indicates that the active picture area of a video line is beginning.

Ride Film - A Ride Film is a program that is intended on being finally viewed by an audience that is in a simulator. Typically a ride film is a POV (point of view) program such as would simulate riding in a vehicle or experiencing someone's POV.

Rolor - Real color depth expressed in terms of human vision and not "bits per pixel"

SAMPLING - The process of repeatedly measuring the instantaneous levels of an analog signal at regular intervals in order to produce a digital representation.

SAMPLING FREQUENCY - The number of discrete sample measurements made in a given period of time.

SDI (Serial Digital Interface) - As specified in SMPTE Standard 259M.

Set-up(s) - During first unit production, a set-up is a particular arrangment of sets, props and actors that are to be photographed. Typically, the efficiency of a production unit is described as its ability to perform a number of "set-ups" in a day.

Slot - As in an actor's availability, principal actors have avaibilities between previous commitments that are described as "slots".

SPARKLIES - See "Impulse Noise"

Speed - When we include all the transfer times, the effect of a shutter, if any, the effective speed of the system shall be expressed in FPS ( frames per second ). The base speed for a digital production camera system shall be 24 FPS.

Stop or Stops - The number of stops represents the range of light intensity which the system can effectively portray. A stop on s "Digital Production Camera" will be equal to an f-stop on a film camera.

T-1 CIRCUIT - A T-1 circuit or leased line equals 1,544,000 bits per second or 24, 56 kbs leased lines.

T-3 - A T-3 Circuit (45,000,000 bits per second) is the minimum backbone speed of all major national ISPs in the United States.

TEMPORAL ALIASING - A visual defect that occurs when the image being sampled moves too fast for the sampling rate. A common example is wagon wheels that appear to rotate backwards.

THUMBNAIL - A low-resolution version of an image that gives the viewer a quick reference to what the image will look like full size.

TRAILING DOTS - Cross-luminance near sharp saturated moving color edges due to the failure of the chrominance filter in the temporal dimension and thus providing incomplete Y/C separation.

TRANSCODING - The process of converting from one production format to another. This may include up conversion, down conversion, translation, de-interlacing, component to/from composite coding and time compression/expansion.

TRANSLATION - A process that converts an image stream from one temporal sample structure to a higher or lower temporal structure. i.e. 3:2 pull down to convert film (24fps) to video (30fps).

TRANSPORT STREAM (MPEG) - A bit stream packaging elementary streams together. It can accommodate several programs with independent clocks. Transport streams have fixed length packets and are intended for transmission over error prone channels. This stream is often called simply the MPEG signal.

Trixel - The time taken to transfer a single pixel through the entire proposed data path. Assume to be large enough to measure on know time-scales.

UP CONVERSION - A process that resamples an image in order to produce an image with more pixels than are in the original image.

Video Tap - When a video camera is mounted on the viewfinder of a motion picture camera, we then call that video camera a "video tap" It is used to allow others to view what the camera operator sees through the optical viewfinder. The image generated from the video tap is often combined with other recorded or generated images to preview a possible composite that is to be performed in post production.

Virtual Set - A virtual set is one that is an alternative to a set built with nails, wood, plaster or other construction materials. Virtual sets are generated electronically and can be manipulated by means of 3D image processing to simulate what would otherwise be a real physical set.

Y, Cr, Cb - The digital luminance and color difference signals in ITU-R BT.601 coding. The Y luminance signal is sampled at 13.5 MHz and the two color difference signals are sampled at 6.75 MHz co-sited with one of the luminance samples. Cr is the digitized version of the analogue component R-Y, Cb the digitized version of B-Y.

Y, R-Y, B-Y - The luminance, Y and color difference signals, R-Y and B-Y, of analog component television. Y is pure luminance information while the two color difference signals together provide the color information.

YIQ - Shorthand commonly, but incorrectly, used to describe the signals in analog component video. Y is correct for luminance, but, I and Q are the two subcarrier modulation axes (I - inphase quadrature) used in the NTSC system. Scaled and filtered forms of the R-Y and B-Y color difference signals are used to modulate the NTSC subcarrier in the I and Q axes respectively.