A Glossary of Film and Video Terms

3:2 Pulldown The technique used to convert 24 frames per second film to 30 frames per second video. Every other film frame is held for 3 video fields resulting in a sequence of 3 fields, 2 fields, 3 fields,2 fields, etc. (See Fields, Frames)

4 fsc Composite Digital video as used in D2 and D3 VTRs. Stands for 4 times the Frequency of Subcarrier, which is the sampling rate used.

4:2:2 The sampling ratio used in the D1 (CCIR 601) digital video signal. For every 4 samples of luminance there are 2 samples each of the color difference signals, R-Y (Red minus Luminance) and B-Y (Blue minus luminance).

4:1:1 The sampling ratio used in the DV or DVC (Digital Video, Digital Video Tape) digital video signal. For every 4 samples of luminance there is 1 sample each of the color difference signals, R-Y (Red minus Luminance) and B-Y (Blue minus luminance).

4:2:0 The sampling ratio used in some variations of DV digital video signal. For every 4 samples of luminance there is a sample of one of the color difference signals, followed by a sample of the other color difference signal on the next luminance sample.

4:4:4 A sampling ratio that has equal amounts of the luminance and both chrominance channels. Can also be used for RGB sampling, the color space used in most computer programs.

16×9 (16 by 9) A wide screen television format in which the aspect ratio of the screen is 16 units wide by 9 high as opposed to the 4×3 of normal TV.

A-Frame Edit A video edit which starts on the first frame of the 5 video frame (4 film frame) sequence created when 24 frame film is transferred to 30 frame video (see 3:2 pulldown). The A-frame is the only frame in the sequence where a film frame is completely reproduced on one and only one complete video frame. Here is the full sequence. (The letters correspond to film frames.) A-frame = video fields 1&2, B-frame = video fields 1&2&1, C-frame = video fields 2&1, D-frame = video fields 2&1&2.

A-Mode Edit An editing method where the footage is assembled in the final scene order. Scene 1, scene 2, …

Active Picture Area The part of a TV picture that contains actual image information as opposed to sync or other data. Vertically the active picture area is 486 lines for NTSC and 576 lines for PAL. The inactive area is called blanking.

AES/EBU The digital audio standard set by the Audio Engineering Society and European Broadcast Union and used by most forms of digital audio from CDs to D1.

Aliasing Defects in the picture caused by too low a sampling rate or poor filtering. Usually seen as "jaggies" or stair steps in diagonal lines.

Analog A signal that varies continuously over a range of amplitudes. A digital signal by contrast has only two values, representing 1 or 0.

Artifact A visual effect caused by an error or limitation in the system.

Anti-aliasing The process of removing aliasing artifacts.

Aspect Ratio The ratio of width to height in a picture. Theater screens generaly have an aspect ratio of 1.85 to 1, widescreen TV (16×9) is 1.77 to 1, and normal TV (4×3) is 1.33 to 1.

Auto Assembly An edit in which an off-line edit decision list is loaded into an on-line edit computer and all the edits are assembled automatically with little or no human intervention.

B-Mode Edit An editing method where the footage is assembled in the order it appears on the source reels. Missing scenes are left as black holes to be filled in by a later reel. Requires fewer reel changes and generally results in a faster edit session.

Bandwidth The amount of information that can be passed through a given circuit in a given time. In the case of video, the larger the bandwidth the greater the picture detail can be.

Betacam An analog videotape format using 12.5mm tape developed by Sony and derived from the earlier Betamax. Also includes Betacam SP (Superior Performance), and digital versions Digital Betacam and Betacam SX.

Bit A single element (1 or 0) of digital information.

Bit Rate The amount of data transported in a given amount of time, usually defined in Mega (Million) bits per second (Mbps). Bit rate is one means used to define the amount of compression used on a video signal. Uncompressed D1 has a bit rate of 270 Mbps, DV is 25 Mbps, etc.

Bit Stream A continuous series of bits.

Black Box A term used to describe a piece of equipment dedicated to one specific function, also called dedicated hardware.

Blanking The part of the video signal that contains no picture information. Used for synchronizing, timecode, closed captions, etc.

Broadcast Quality A nebulous term used to describe the output of a manufacturer’s product . Usually at least means that the technical specifications meet the FCC rules for broadcasting.

Bug An error in a computer program. Also something that bites you on a camping trip.

Burned in Time Code Time code numbers that are superimposed on the picture. Also called window burn.

Byte 8 bits. The combination of 8 bits into 1 byte allows each byte to represent 256 possible values. (see Megabyte, Gigabyte, Terrabyte)

CBR Constant Bit Rate. A variety of MPEG video compression where the amount of compression does not change.

CCIR 601 The standard for digitizing component video. Also sometimes called D1 after the VTR format that first used this signal. For NTSC, this standard calls for an image of 720 by 486 pixels sampled at 4:2:2 with a depth of either 8 or ten bits. (see also 4:2:2)

Chrominance The signal which carries the color information in video.

Color Frame A sequence of four fields (2 frames) of NTSC video. Since the phase of the color subcarrier reverses every frame in NTSC (which makes the color information essentially invisible on a black-and-white receiver) two complete frames (four fields) are required to carry a complete sequence of color information. A PAL color frame consists of four frames (eight fields).

Color Subcarrier The portion of the composite video signal that carries the color information. In NTSC, color signals are quadrature modulated onto a subcarrier of 3.579545 MHz.

Component Video A video signal in which the Luminance and Chrominance signals are kept separate. This requires a higher bandwidth, but yields a higher quality picture.

Composite Video The luminance and chrominance signals are combined in an encoder to create the common NTSC, PAL or SECAM video signals. Allows economical broadcasting of video.

Compositing Layering multiple pictures on top of each other. A cutout or matte holds back the background and allows the foreground picture to appear to be in the original picture. Used primarily for special effects.

Compression (Data or Video) The process of reducing the size of digital information, usually by throwing out redundant information.

Compression Ratio The ratio of the amount of data in the original data compared to the amount of data after compression. The higher the ratio the greater the compression.

Control Track A signal recorded on video tape to allow the tape to play back at a precise speed in any VTR. Analogous to the sprocket holes on film.

CRT Cathode Ray Tube. The technical name for a picture tube, a camera tube or the scanning tube in a flying spot telecine.

Cutout (see matte)

D1 Digital video tape format using the CCIR 601 standard to record 4:2:2 component video on 19mm tape. Currently the highest quality video tape format generally available. The first digital video tape format, hence D1.

D2 Digital video tape format using the 4fsc method to record composite digital video. Uses 19mm tape and a cassette similar to D1. The second digital video tape format, hence D2.

D3 Digital video tape format using 4fsc composite signals like D2, but recorded on 12.5 mm (1/2-inch) tape. The third digital video tape format…

D4 Doesn’t exist. The number 4 is considered unlucky in Japan.

D5 Digital video tape format using CCIR 601, 4:2:2 video. Uses the same cassette as D3. Betcha can guess why it’s called D5.

D9 Digital video tape format using CCIR 601, 4:2:2 video compressed about 3:1. The same as "Digital S".

DCT Discrete Cosine Transform. A widely used method of video compression. Also an Ampex CCIR 601 digital VTR using DCT to compress the video before recording it to tape.

Digital A form in which everything is defined by a series of numbers, usually ones and zeros (binary).

Digital Betacam Digital video tape format using the CCIR 601 standard to record 4:2:2 component video in compressed form on 12.5mm (1/2-inch) tape.

DDR Digital Disk Recorder A digital video recording device based on high speed computer disk drives. Commonly used as a means to get video into and out from computers and for editing.

Digitizing The act of taking analog video and/or audio and converting it to digital form. In 8 bit digital video there are 256 possible steps between maximum white and minimum black.

DV Digital Video. A digital tape recording format using approximately 5:1 compression to produce Betacam quality on a very small cassette. Originated as a consumer product, but being used professionally as exemplified by Panasonic’s variation, DVC-Pro, and Sony’s variation DVCam. These formats use a 25 Mbps data rate and use 4:1:1 sampling. A variation, DVC-Pro 50, uses a 50 Mbps data rate and 4:2:2 sampling.

DVD Digital Video Disk (or Digital Versatile Disk). A format for putting full length movies on a 5" CD-like disk using MPEG-2 compression. Produces the highest video quality in a consumer format.

DVE Digital Video Effects. A "black box" which digitally manipulates the video to create special effect. Common DVE effects include inverting the picture, shrinking it, moving it around within the frame of another picture, spinning it, and a great many more.

Edge Numbers Code numbers printed on the edge of 16 and 35mm motion picture film every foot which allow frames to be easily identified in an edit list.

EDL Edit Decision List. A list of edit decisions made during and edit session and usually saved to floppy disk. Allows an edit to be redone or modified at a later time without having to start all over again.

Field One half of a complete interlaced video picture (frame), containing all the odd or even scanning lines of the picture.

Frame One complete video image, containing two fields. There are 30 frames in one second of NTSC video.

Gigabyte 1 Billion bytes.

HDTV High Definition Television. Any of several TV formats capable of displaying on a wider screen (16×9 as opposed to the conventional 4×3) and at higher resolution than standard-definition TV (SDTV).

Interlace A process in which the picture is split into two fields by sending all the odd numbered lines to field one and all the even numbered lines to field two. This was necessary when there was not enough bandwidth to send a complete frame fast enough to create a non-flickering image.

ISDN Integrated Services Digital Network. Allows computers to communicate over existing phone lines using a digital telephone network at much higher speeds than are possible with an analog modem. Being used for high quality audio in real-time transfer.

ITS The International Teleproduction Society.

ITVA The International Television Association.

JPEG Joint Photographic Experts Group. A standard for compressing still pictures and video images in a form suitable for frame-by-frame editing.

Keykode A machine-readable code printed on the edge of motion picture film which allows the film edge numbers to be electronically read and inserted into an edit list. Very useful for generating a negative cut list from a video off-line EDL.

LTC Linear Time Code. Time code recorded on a linear analog track on a video tape. Also called Longitudinal Time Code.

Letterbox Placing a wide screen image on a conventional TV by placing black bands at the top and bottom of the screen.

Luminance The black and white, or brightness, part of a component video signal. Also called the "Y" signal.

Matte A black & white high contrast image that suppresses or cuts a hole in the background picture to allow the picture the matte was made from to seamlessly fit in the hole.

Megabyte 1 million bytes.

MPEG Moving Picture Experts Group. A group of standards for compressing moving pictures. MPEG 1 originally used a data rate of 1.5 Mbps (Mega Bits per Second) to record video on CD-ROM. MPEG 2 supports higher quality with a data rate (also called bit rate) of from 2 to 10 Mpbs. MPEG 2 is the format used for satellite broadcasting (DSS), digital terrestrial broadcasting, and DVD.

Non-Linear Editor An editing system based on storage of video and audio on computer disk, where the order or lengths of scenes can be changed without the necessity of re-assembling or copying the program.

NTSC National Television Systems Committee. The name of the television and video standard in use in the United States. Consists of 525 horizontal lines at a field rate of 60 fields per second. (Two fields equals one complete Frame). Only 486 of these lines are used for picture. The rest are used for sync and extra information such as VITC and Closed Captioning.

Off-Line Editor A low resolution, usually computer and disk based edit system in which the creative editing decisions can be made at lower cost and often with greater flexibility than in an expensive fully equipped on-line suite. See also Non-Linear Editor

On-Line Editor An editing system where the actual video master is created. An on-line bay usually consists of an editing computer, video switcher, audio mixer, 1 or more channels of DVE, character generator, and several video tape machines.

PAL Phase Alternate Line. The television and video standard in use in most of Europe. Consists of 625 horizontal lines at a field rate of 50 fields per second. (Two fields equals one complete Frame). Only 576 of these lines are used for picture. The rest are used for sync or extra information such as VITC and Closed Captioning.

PALplus A widescreen (16×9) television standard in use in Europe that is compatible with existing 4×3 TV sets. Non-16×9 TVs show the picture in a letterboxed form.

Pixel Short for Picture Element. The basic unit from which a video or computer picture is made. Essentially a dot with a given color and brightness value. D1 images are 720 pixels wide by 486 high. NTSC images are 640 by 480 pixels.

Resolution The amount of detail in an image. Higher resolution equals more detail. Generally expressed in "lines". It is the number of VERTICAL line pairs that the system can distinguish, and has no relationship to the number of horizontal scan lines. Also used to describe the size of a computer image, usually in pixels.

Resolution Independent A term to describe equipment that can work in more than resolution. For example, most equipment can do film resolution or video resolution, but not both. Resolution independent equipment can work in both.

RGB Red, Green, Blue. The primary colors of light. Computers and some analog component devices use separate red, green, and blue color channels to keep the full bandwidth and therefore the highest quality picture.

Sampling Frequency The number of sample measurements taken from an analog signal in a second, generally expressed in MegaHertz. These samples are then converted into digital numeric values to create the digital signal.

SMPTE Society of Motion Picture and Television Engineer. A major standards-setting organization for the motion picture and television industries. Established the standards for time code and for all the major video tape formats.

Telecine A device that creates video from motion picture film.

Terabyte 1 trillion bytes.

Time Code A time reference recorded on tape to identify each frame.

Vaporware Software or hardware that is talked about, but may never actually appear.

VBR Variable Bit Rate. MPEG video compression where the amount of compression can be varied to allow for minimum degradation of the image in scenes that are harder to compress.

VCR Video Cassette Recorder.

VHS Video Home System. 1/2-inch consumer video cassette recorder.

VTR Video Tape Recorder.

VITC Vertical Interval Time Code. Timecode stored in the vertical interval of the video signal. Has the advantage of being readable by a VTR in still or jog. Multiple lines of VITC can be added to the signal allowing the encoding of more information than can be stored in normal LTC.

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