DVD glossary

s

One second of time.

Sample

Value of an analog or continuous signal at a single point of time (see Digitize.)

Scanning Velocity

Linear velocity at which optical data features pass a fixed point such as the pickup head of a drive.

Scarlet Book

Proprietary Philips/Sony specification (scarlet cover) for a Super Audio disc of one DVD layer and one CD layer.

Section

CD information group containing 98 consecutive frames of interleaved bytes from scrambled sectors, plus C1 and C2 CIRC, subcode, and frame sync. Also referred to as a subcode block.

Sector

Smallest addressable entity in the information area that can be addressed independently of other addressable parts.

Servomechanism

Electromechanical means of automatically maintaining a desired state by sensing variations from that state, and then correcting those variations by using very small amounts of power to control much larger amounts of power.

Session

Single recording event that creates a single information area (lead-in - program area - lead-out.)

Single Session

Single recording event resulting in one lead-in (with TOC), program area, and lead-out for the entire disc.

Skew

See deviation.

Space

High reflectance feature of a recording layer representing data that can be sensed by an optical system.

Spindle

Mechanical means of coupling a disc to a rotating device.

Stamper

The electroformed part made from a mother and containing a reversed data image of the final disc. Becomes part of a mold for the injection molding replication process.

Standard for Recording

A document agreed upon by the originator and recipient of a volume specifying the recording and addressing methods for information, including;

a unique physical address for each recorded sector, and

the location of the data field within each sector, and

the length of the data field within each sector.

Subcode

Ninety-eight-bit codes used in the CD format. P and Q codes contain flag and control information. Codes R,S,T,U,V,W are available and may be used for CD+G or other specialized applications.

Subcode Block

See Section.

Substrate

Transparent physical layer providing mechanical support through which the laser can access an information layer.

Sync

Unique bit pattern appended to and preceding information that establishes a reference point for decoding of that subsequent information.

System Area

The first sixteen logical sectors in a CD volume numbered 0 to 15.

S/PDIF
Sony/Philips Digital Interface. The standard for transmitting digital data (like Dolby Digital) on consumer-grade components. Uses either a 75-ohm coaxial or TOSLINK optical cable.

Sampling
Process of creating a digital representation of an analog signal. Standard CD PCM is sampled at a rate of 44.1 kHz (44,100 "samples" of the sound are taken per second).

Saturation
The amount of gray, as opposed to hue, in a color-the intensity of the hue.

Scanning velocity
Rate at which the laser pickup beam travels along the spiral track.

SCART
The standard European AV connector/socket for TVs, VCRs, and DVD players.

Scene Access
You do not have to watch a DVD from beginning to end, or use fast forward and rewind to access a particular scene. You may pick from a list of chapters to get to a certain scene, which is usually accessed via the menu, or by pressing the corresponding chapter number on the remote.

SDDS
Sony Dynamic Digital Sound. Sony's discrete multi-channel surround sound available only in theaters. SDDS is available in 6-channel or 8-channel varieties.

Seamless Branching
DVD has the capacity to switch instantaneously between separate and distinct video, audio and subtitle "streams" or tracks. This is done via complex coding commands, but unfortunately has not yet been widely exploited. (See also Multiple Video Tracks, Multiple Audio Tracks and Subtitles)

Sector
Logical collection of bytes at the data layer (after de-interleaving). At the physical layer, a sector consists of 38, 688 channel bits.

Sector information
Header field providing the sector number.

Sector number
A number that identifies the physical sector on a disc.

Sequence
MPEG definition of a set of coded pictures that are dependently coded. Within a sequence, all pictures adhere to a common bitrate (CBR), buffer size, picture size, aspect ratio, and frame rate.

Skip
Another DVD playback anomaly. See Jump.

Still Gallery
DVD has the ability to display a single video frame at a time, for perfect still images. (This is quickly noticeable when the pause button is pressed during playback.) The best use of this capability is to take a collection of images and allow the viewer to page through them with the remote control skip buttons. Still frame files are generally used for behind-the-scenes photographs, promotional artwork, storyboards or conceptual art. A DVD can easily hold thousands of images or more.

Sub-picture
A simple picture intended to be superimposed over the video. Variable in display size but bounded to CCIR 601 picture dimensions (720 x 480 for NTSC-rate displays or 720 x 576 for PAL-rate displays).

Substrate
The clear material (polycarbonate) that surrounds and protects the stamped information on a DVD. The substrate is thin and helps the DVD ensure greater accuracy in the laser pick-up, because the laser is less likely to refract. It's a DVD half-disc. Two substrates, each 0.6 mm thick, are bonded together to form a 1.2 mm thick DVD disc.

Subtitles
A subtitle stream places text on the screen for the viewer to read, and is essentially used for dialogue. Subtitles can be in any number of languages, So that the viewer who does not speak the native language of the movie can view the movie and read what the actors are saying. DVD allows for up to 32 subtitle tracks. Closed Captioning is an extended form of subtitling, wherein additional text is displayed with aural sound descriptions to aid hearing-impaired individuals better understand action on screen. Note that a Closed Captioning decoder is required to receive captioning encoded on a disc. However, by law all new televisions must have built in Closed Captioning decoders.

Subwoofer
A speaker designed to reproduce bass (low frequencies). Bass is not very directional, so most home cinema systems only need one mono bass channel.

Surround Speakers
Used in a ProLogic, Dolby Digital or other surround system. In a ProLogic system there is typically 5 speakers; center, front left, front right, and rear left and right carrying the same mono signal. In a Dolby Digital/DTS system the rear speakers carry a stereo signal, and there is usually an additional subwoofer. It is also possible to add additional subwoofers, dipole rear speakers and so on.

S-Video Output
Unlike the RGB Component output, S-Video modulates the video signal in its separate parts -- chrominance (color) and luminance (light and dark). This makes for a more precise, detailed picture than RF.