Television and Video Glossary -- S

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S/N -- Signal to Noise Ratio.

S-VHS or SVHS -- Super VHS -- A variation of the VHS videotape format where the luminance resolution is about 400 TV lines. (The color resolution is the same as regular VHS, about 32 lines.) S-VHS VCRs will play regular VHS tapes and can record in regular VHS format as well, but regular VHS VCRs will not play S-VHS format tapes. Because S-video (separated Y and C) cabling was originally used for S-VHS VCR's, the term S-VHS is sometimes mistakenly used when "S-video" was intended.

S-Video -- Super video, also called Y/C -- A video signal transmitted as two subsignals requiring two separate wires: luminance (technically referred to as Y) and color (C). Although commonly found in S-VHS VCR's, this signal is not limited to such VCR's. Note: The C portion is already modulated on a subcarrier, 3.58 MHz (approx) for NTSC as if to be combined with the Y portion to become composite video, except not necessarily bandwidth limited to meet broadcast specs. Note: S-video can represent todays standard definition interlaced video signals only. Looking into the S-video cable plug, with the plastic pin in the 6 o'clock position, upper left (metal) pin is luminance, upper right pin is color, center metal pins are ground for the respective pins above them. Luminance and color are recorded as separate signals on all VCR's, using different subcarrier frequencies than S-video.

SACD -- Super Audio Compact Disk (made by Sony)

Safe Area -- The portion of the picture area, usually marked so in the camera's viewfinder, where important material, action, or text titles should be confined to. The purpose is to make sure that everything important can be seen even when the TV set has a lot of overscan, or to create movie and video programs that can be acceptably cropped into a choice of two or more picture aspect ratios. For video, the safe action area, where important subject matter is generally confined to, is the inner 81% of the picture area after discounting edge strips 5% of the respective screen dimension in width. The safe title area, used for positioning text such as credits, is the inner 64% of the picture area after discounting edge strips 10% of the respective screen dimension in width.

Sampling -- The process of converting an analog entity (such as a picture or a soundtrack) to digital form. In the case of a picture, a large number of evenly spaced spots (samples) are taken and each represented as one or more numbers for brightness (luminance) and color. These spots are referred to as picture elements or pixels. The more samples are taken, the more accurate (with higher resolution) an image can be reconstructed from the samples. For DVD, the image is 720 samples wide by 480 samples high for a total of 345,600 samples (may vary slightly). Even analog TV has sampling; each scan line is a discrete (as in digital) sample in the vertical direction although it is continuous (analog) in the horizontal direction.

SAP -- Second Audio Program.

Satellite Speaker -- Speaker system with mid-range and tweeter speakers (or a single speaker for mid- and high frequency sounds), suitable for being mounted on a wall or ceiling and intended to be used together with a woofer in a separate cabinet. Many sound systems have several satellite speakers for surround sound and just one woofer or subwoofer given that listeners generally cannot tell from what direction low frequencies come.

Scaling -- The reformatting of video or digital pictures to occupy a different number of scan lines or a different number of discrete pixels horizontally or vertically. Scaling is also referred to as "resampling". See Sampling. Scaling is done to zoom an image on the screen without spreading out the existing scan lines, or to change the video from one format to another, for example HDTV to NTSC or NTSC to SECAM. Video Scaler -- Electronic device used to perform scaling, usually with a choice of scalings not necessarily an even multiple or fraction of the original scan line or pixel count.

(Horizontal) Scan Rate or Scan Frequency -- Number of scan lines per second, including scan lines representing the vertical retrace interval, usually expressed as kilohertz. In the U.S., for NTSC it is about 15.73 KHz, for 1080i HDTV it is about 33.75 KHz, for 720p HDTV it is about 45.0 KHz.

Scan Velocity Modulation -- An electronic means of automatically varying the speed of the electron beam as it sweeps across the screen, so as to make light to dark transitions representing edges of subject matter more sharply defined. Advanced videophiles tend to disfavor it, turning it off whenever possible.

SCART (Syndicat des Constructeurs d'Appareils Radiorecepteurs et Televiseurs)-- Refers to a 21 pin plug and jack combination often used in European video equipment. It carries both video and audio, offering a choice of carrying composite video and S-video, composite and component video, or composite and RGB. Also called a "Euro" or a "Perri" connector.

Screen Door Effect -- The fine grid of thin dark horizontal and vertical lines resulting from the gaps between illuminated spots (pixels) in a (usually projected) picture generated using digital displays such as LCD.

Screening Room -- A small private theater, typically used by movie producers, reviewers, and critics.

SDE -- Screen Door Effect.

SDI -- Serial Digital Interface -- A set of standards for digital transmission of video over 75 ohm coaxial cable preferably using BNC connectors.. For video it usually uses a 270 megabit per second data transmission rate and it supports the standard NTSC based video formats and ATSC video formats. It is suitable for transmission over 100 feet contrasted with DVI and HDMI which are limited to about 30 feet. The data formats are not the same as for DVI or HDMI which are also in widespread use today (2005).

SDTV -- Standard Definition Television.

SECAM (Sequential Couleur Avec Memoire)-- A 625 line 50 interlaced field per second analog broadcast standard originally used in Europe, primarily in France. Alternating scan lines carry R-Y and B-Y color difference signals respectively. The TV must contain delay (memory) circuits to make available both the R-Y and B-Y signals, which are then shared by (as common to) each pair of scan lines. Chroma resolution is half the luminance resolution vertically. Programs are not interchangeable with NTSC even though they may occupy the same broadcast channels or be recorded on videocassettes of the same size and shape. Programs can be played back on PAL equipment where they come out in black and white. There exist VCR's and TV sets that will play all three formats but they are not common in the U.S.A.

Second Audio Program -- An audio program or track other than used for stereophonic sound, such as the same program in a different language, or unrelated material such as weather forecasts, transmitted as the subordinate audio subchannel in a TV broadcast and receivable on TV sets with MTS (multichannel TV sound).

Segmented Frame -- One method of transmitting film source video, where each film frame's video is transmitted as two parts or segments, specifically odd scan lines and then even scan lines, that is, as if interlaced. Unlike traditional interlaced video with 3-2 pulldown, each field's worth of content is transmitted just once, and the overall frame rate is 24 (23.976 for NTSC) complete frames per second for U.S. films. It is still referred to as progressive scan since each pair of segments is (or should be) derived from the same film frame or source image. The notation often juxtaposes the letters P, S, and F, as in 480psf24 and this should not be confused with "fps" for simply "frames per second". (We use the notation 480p@24fps or 480p@24 or 480@24p when including the frame rate.)

Selectavision -- Trademark of Thomson Electronics (which acquired Radio Corporation of America; RCA), refers to certain VCR's and a now obsolete playback only video disk system that RCA marketed. See, also, CED.

Set Top Box -- Currently refers to an external tuner for HDTV broadcasts, typically placed on top of a "boxy" TV set.

sf -- See Segmented Frame.

7.1 -- Sound system with left, center, and right front speakers, left and right side speakers, left and right rear speakers, and a subwoofer. See Surround Sound.

75-Ohm -- Refers to TV antenna connections made using a round (coaxial) cable. Also refers to the impedance of all common video connections. For video cables, almost any cable will transmit an intelligible picture but the correct impedance is 75 ohm and also cables should have adequate bandwidth.

Shadow Mask or Aperture Grill -- A grill with holes or slots mounted about an inch behind the glass screen of the picture tube. It physically constrains the electron beam intended for the red phosphor dots (or stripes) from hitting anything but the red phosphor dots, and so on. Normally the exact shadow mask that will be installed in a picture tube is used to assist in printing the phosphor dots on the screen of that picture tube, as the optical process of printing the phosphor dots closely mimics the path of the electron beam. Mating a shadow mask with a screen panel early in the manufacturing process prevents slight variations from one mask to another from affecting the quality of the finished picture tubes.

Shimmering -- (1) Flickering halos or pinpoints of light caused by stray light rays from imperfect rear projection screen layers, which contain lens elements or from processing of the video signal by imperfect electronics. (2) Accentuated flicker of thin picture details moving up or down at certain speeds that interact with the scan rate.

Shrill -- Refers to sound with an abundance of content in the mid treble (1000 to 3000 Hz) range, often sounding obnoxious or even approaching the pain threshold due to this content.

60i as in 1080@60i-- 60 or 59.94 (interlaced) fields per second, each field with half as many scan lines as the number preceding the at sign (as the 1080 in the example). Also 48i, etc. for 48, etc. fields per second for example used in some film source transmission formats. Also 60p or 60, 30p or 30, etc. for that many (progressive scan; full) frames per second.

Skating -- Tendency of a phonograph tone arm to swing, usually towards the center of the record as the record rotates, which tendency puts an undesired greater stylus pressure on the groove inner wall compared with on the groove outer wall. Anti-Skating -- Mechanical compensation, usually involving springs, that counteracts skating. Calibration is typically done using a "record" with no grooves.

SKU -- Stock Keeping Unit, see below.

SLP -- Super Long Play; Extended Play.

Slug, or Tuning Slug -- A movable ferrite core used to adjust a coil's behavior (inductance). May be the screwdriver (sometimes hex wrench) adjustments in back of a TV to adjust convergence, etc.

Small -- Setting on an amplifier that reduces the amount of low frequencies delivered to speakers other than a subwoofer. The purpose is to prevent overdriving the other speaker systems (which may be physically small) with the lower frequencies, and may be required with certain types of speakers. On some amplifiers the small setting is required to activate the subwoofer channel.

Smart TV -- A TV set with two way communication with a program provider which could include a cable TV company. The TV set can transmit requests to and receive customized information and programming as opposed to only prescheduled shows already in progress. Usage ranges from video (shows) on demand to program guide and other information requested by the viewer. Required is a usually subscription based program provider such as Apple TV, Hulu, Disney Plus, or even the internet, that the TV set was pre-equipped to communicate with and which has a library of or access to desired shows. (2) The concept of video on demand and two way communication between program provider and TV set (receiver).

SMPTE -- Society of Motion Picture and Televison Engineers, also standards for video signal formats, video production and television set calibration said society has developed.

Soft Matte -- Refers to wide screen movies that were actually filmed wide-angle using the entire 4:3 aspect ratio film frame and where the projectionist adjusts mattes (aperture plates) to hide the top and bottom edges leaving the middle as a wide screen view. Sometimes what will become a wide screen film is shot in the 4:3 aspect ratio so that when committed to video, the entire width of the picture can be included and also the entire TV screen would be filled. Sometimes the top and bottom edges intended to be matted are not suitable for inclusion in a video edition because the special effects added later fell short of these areas or because extraneous things such as microphone booms were caught in those areas. This writer believes that when a wide screen movie that was shot soft matte is offered on video with extra material of interest such as director's notes, scenes from alternate scripts, or behind the scenes footage, the movie itself should be transferred to video unmatted if not anamorphic. The material at the top and bottom edges is behind the scenes material that can be given free of charge on a spherical transfer with no extra effort by the producer and no loss of picture quality.

Soft Telecine -- Encoding film source as 24 fps on a DVD or other digital media and the player duplicates frames or fields as needed (3-2 pulldown, etc.) to output the proper frame rate to the TV.

Software -- Programs, instructions, applications, data that are loaded into a computer or other electronic (or sometimes mechanical) device and that can be readily removed to make space for other such material or when no longer needed. Software can also refer to recorded music, movies etc. "Software would be the array of holes in a player piano roll; the roll itself is the storage medium (plural: storage media)".

Solarization -- Above a certain level of brightness, what should be brighter content shows up as darker, giving a partial photographic negative effect. For a gray scale test pattern you might see: black, very dark gray, dark gray, medium gray, light gray, very light gray, light gray, medium gray instead of white where white belongs. Usually this indicates some malfunction in the video circuitry or display element. Solarization can occur when film is overexposed and the effect is sometimes used intentionally and artistically for photographs.

Sonotube -- Trademark for a line of rigid cardboard (not corrugated) cylinders available in varying sizes and used as forms for poured concrete pillars and footings. Sometimes used for speaker enclosures.

Sound Pressure Level -- A measure of the intensity of sound or audio.

SP -- Standard Play, as opposed to a later introduced extended play or long play modes using similar equipment and media...

SPDIF -- Sony - Phillips Digital Interface -- Format for transmitting audio digitally over coaxial cable.

Spatially Adjacent -- Refers to scan lines immediately juxtaposed on the screen. The term is needed when discussing interlaced video where juxtaposed lines are (for NTSC) 1/60 second apart in terms of when they were transmitted, received, and "drawn". See, also, Temporally Adjacent.

Spherical -- Opposite of "anamorphic"; refers to photography or cinematography where a picture is recorded in its actual horizontal to vertical proportions. That is, it is not "squished" to fit on a film frame with a lower (usually 4:3) aspect ratio and where a special lens would be needed to project it in the correct proportions. In the case of a wide screen movie, the image occupies the center portion of the film frame and the top and bottom edges of the frame are hidden by the projector aperture plates if they were not already covered and left blank by similar plates in the camera during filming. Also, having the curvature of the surface of a sphere or part thereof. At one time, color picture tube faces were spherical where the sphere radius was equal to the distance from screen to electron gun, so that it was easier to design the picture tube and supporting electronics to have little or no convergence or focusing errors.

Spider -- (1) The part of a speaker cone's suspension at the voice coil that keeps the voice coil centered within without rubbing against the magnet assembly while permitting axial (in and out) movement of the voice coil. (2) An insert that fits in the center hole of a 45 RPM record to allow the record to be played on a (multi-speed) phonograph with a smaller center spindle.

SPL -- Sound Pressure Level.

Spoke Time -- Time, usually expressed in percent, when a boundary between two color cellophanes in the color wheel of a single chip DLP projector or similar projector is crossing the light beam. During this time all pixels in the display element must represent black as the beam is in two colors and it is impossible to predict the proportions. The larger each cellophane is relative to the display element the lesser the spoke time is. A lesser spoke time means more overall light output from the projector, all other things being equal.

Square Wave -- Waveform which when drawn graphically consists of straight up, straight across, straight down, straight across, straight up, and so on. In terms of frequency content it consists of a fundamental and all of the odd harmonics in certain proportions. The significance of a square wave in amplifier testing is that frequency response and presence of certain distortions can be evaluated by examining on an oscillocope the reproduction of square waves of just a few different fundamental frequencies.

Squawker -- Mid-range speaker.

Squeeze Trick -- See Vertical Squeeze Trick.

Stairstepping -- The jagged appearance of sloped lines or edges inherent to the reproduction of a picture using pixels and/or horizontal scan lines.

Standard Definition -- Refers generally to NTSC and PAL, and to digital or analog TV signals and equipment that provides picture quality roughly the same as NTSC, that is, having about 500 scan lines and with the smallest picture details a little wider than 1/1000'th the screen width.

Standard Play -- The fastest (usually first introduced) tape speed on a VCR or VTR, yielding the best recording quality although the least recording time for a given tape.

Stock Keeping Unit (SKU) -- -- A unique number associated with a manufacturer and model/style of merchandise to keep track of inventory in factories, warehouses, and stores. Usually pronounced "skew" rather than "escayoo" or as the entire phrase.

STB -- Set Top Box.

Studio Monitor -- Marketing term for a TV receiver, TV monitor, or sometimes just a speaker system intended for use in studios to permit monitoring of a program during production or prior to broadcast and which unit is supposedly of a higher quality than similar products marketed to consumers.

Stylus -- "Needle" for a phonograph. The term may refer to either just the pointed tip (nowadays usually a tiny diamond) that traces the record groove, or the entire replaceable assembly that includes the tip, a shank the tip is part of or attached to, and perhaps other components such as a small magnet (if the phonograph cartridge uses electromagnetic coils), mounting infrastructure, and/or protective blocks.

Subwoofer -- Speaker or speaker system for reproducing the lowest audio frequencies, typically under 100 Hz., each cabinet generally not also equipped with speakers to reproduce the higher frequencies. Reproducing low frequencies requires larger speakers and more amplifier power while low frequencies are less directional. This allows a sound system to have just one subwoofer system ,and the rest of the speakers and supporting audio components can be smaller, lighter, and less expensive.

Super Long Play -- Extended Play, q.v.

Surround Sound -- Generic term to describe a sound system with speakers both in front of and behind the audience.

(2.0 -- Left and right front speakers only, not surround sound)

2.0 Surround -- Left front, right front, and center rear speakers.

(3.0 -- Left, center, and right speakers all in front, not surround sound.)

4.0 -- System with left and right front speakers, and left and right rear speakers.

5.0 -- Has left, center, and right speakers in front, two speakers in the rear.

6.0 -- Has left, center, and right front speakers, and left, center and ight rear speakers.

7.0 -- Has left, center, and right front speakers, left and right side speakers, left and right rear speakers.

All: With point one (.1) instead of point zero -- Has a subwoofer in addition to the other speakers. Low frequencies are not directional so only one subwoofer is needed.

Some amplifiers and A/V receivers will synthesize added sound channels if the source material has fewer sound channels than there are speakers.

SVGA (Super VGA) -- 800x600 resolution. See VGA

SVM -- Scan Velocity Modulation.

SVOD -- Subscription Video On Demand. See VOD.

Sweet Spot -- (1) A relatively small area in a room, auditorium, or theater where the best quality of sound is heard or where monitoring is done for the best sound quality when a sound system is calibrated. "Sweet spot" can also describe viewing positions for live performances involving scenery although for movies the area where the view is close to its best is usually quite large. (2) The set of parameters such as number of scan lines and electron beam spot size where equipment such as a CRT TV set that accepts a continuous range of scan rates performs at its best. In the case of the preceding example the best picture quality is obtained when the scan lines barely overlap, with minimal blurring and without distinguishable gaps.

Swishing -- In analog tape playback, the fading in and out of higher audio frequencies due to changing of the azimuth of the tape head gap as the angle of the tape's passage across the head changes in worn or lesser quality equipment..

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