DVD glossary

Label

Printed information on the surface opposite to the entrance surface. Note that the label side of a CD contains metallized pits and grooves, and usually employs a protective coating under the printed information.

Lacquer Splash

Dried protective coating material on the entrance surface or outer rim.

Land

Unrecorded optical surface area between pits, grooves, or marks, further away from the entrance surface than pits.

Laser

Light Amplification by Stimulated Emission of Radiation generates monochromatic, coherent light, usually from an excited gas or semiconductor.

Laser Beam Recorder (LBR)

Recording apparatus consisting of a gas laser that is intensity modulated by a data encoder and position controlled radially by an accurate lathe mechanism. The laser beam is incident upon a glass master rotated by a spindle motor having accurate speed control.

Lead-In

Area at the beginning of a disc or session containing the Table of Contents (TOC) and other important information. Lead-in is followed by the Program Area.

Lead-Out

Buffer area following the Program Area used in case the player reads past the track.

Length Deviation

Variation of effect length from a norm.

Linear Velocity

Linear speed at which a moving feature passes a fixed point (also see Scanning Velocity.)

Link Block

Identified or unidentified region containing errors at the boundary of two different incrementally recorded data regions.

LaserDisc
A 12-inch optical disc originally called LaserVision. Laserdisc offers 425 lines of horizontal resolution, which results in picture quality that is superior to VHS tape, but not quite as good a s DVD (480 lines of resolution).

Laserrot
A physical problem with a disc, caused by a manufacturing defect, that causes a laserdisc to become unplayable.

Layer 0
In a dual layer disc, this is the layer closest to the optical pickup beam and surface of the disc. Dual layer discs are 10% less dense than single layer discs due to crosstalk between the layers.

Layer 1
In a dual layer disc, this is the deeper of the two layers.

Lead-in
Unused physical area at the start of the continuous track spiral.

Lead-out
Unused physical area at the end of the continuous track spiral.

Letterbox
A term used to describe the presentation of widescreen films on an Academy aspect ratio (1.33:1) display. Black bars are used at the top and bottom of the picture to create an image that is widescreen.

LFE
Low Frequency Effects. This the surround sound channel used in 5.1 channel surround sound (like Dolby Digital and DTS) used to reproduce low frequency (5-120Hz) sounds. A subwoofer is used to play back the sound.

Linear PCM
Coded audio representation that does not employ compression. Each sample is discretely coded.

Lossless compression
A compression algorithm that does not lose any of the original data during the compression process. The original image or sound is completely preserved.

Lossy compression
Compression after which some portion of the original data cannot be recovered with decompression. Such compression is still useful because the human eye is more sensitive to some kinds of information than others, and therefore does not necessarily notice the difference between the original and the decompressed image.

Luminance
The component of a video signal that includes information about its brightness.