Glossary L-N

L
LaserDisc (or Laser Vision) A video format which uses very large (12-inch) discs. The quality of the picture is better than VHS, but not as good as DVD.
Laser Rot A manufacturing defect on a disc which renders it unusable.
Layer 0 The layer closest to the surface on a dual-layer disc.
Layer 1 The layer below layer 0 on a dual-layer disc.
Lead-In A blank section on a recordable disc which is used to store table of contents data once a session is closed; if the disc is left open for future recordings, the lead-in also contains information about the next part of the disc that can be used.
Lead-Out An area indicating the end of a session; it also closes the session. Unless a session is closed, a player will be unable to “see” the data recorded in it.
Letterbox Adding black bars to the top and bottom of a 4:3 screen to change the aspect ratio to 16:9, creating a “widescreen” playing area.
LFE Low Frequency Effects. A surround sound channel which uses a subwoofer to play sound in the 5–120 Hz range.
Linear PCM An uncompressed audio format with more channels and higher sampling frequencies than even Dolby Digital or MPEG-2 can handle.
Link Block On a recordable disc, a link block is a sector of extraneous bits written by the laser immediately after it is turned on and also when it is turned off.
Linked Multisession A disc containing more than one session, in which all (or selected) data from the various sessions can be seen as if it had all been recorded in a single session.
Logical Block The smallest addressable space on a disc. Each has a unique logical block number (LBN), starting with 0 at the beginning of the disc.
Logical Format (or Logical Structure) A file system that can create a treelike directory of a disc’s contents and can be used to write CDs, such as ISO 9600 or Universal Disk Format (UDF).
Lossless Compression Any compression method that completely preserves data in its original form.
Lossless Linking During disc recording, interrupting and continuing the writing process without any loss of links caused by variable bit-rate encoding.
Lossy Compression Any compression method that sacrifices data in order to reduce file size. These types of compression often rely on the limits of human perception to work: the eye may not be able to tell the difference between an original image and one that has been compressed by limiting the number of colors used in it, or the ear might not notice when sounds above or below a certain frequency are removed from an audio track.
Luminance The brightness component of a video signal.
M
M3U A metafile (file extension: .m3u) that functions as a playlist for MP3 files.
mAC3dec A MAC program that can convert .ac3 files to either .aiff or .mp3 format.
Macroblock See block. Macroblocks are a 16 × 16 array of luma pixels (4 blocks) and a variable number of chroma pixels. It is the basic unit for motion compensation, and can either be field coded or frame coded depending on how the luma pixels are extracted from it. A series of macroblocks is called a slice.
Macrovision A form of copy protection (created by the company of the same name) which scrambles unseen parts of a video signal, preventing the creation of viewable copies.
MacVCD A VCD player for the Mac OS X.
Main Concept Encoder An MPEG encoder which is used in some video editing products, such as Sony Vegas and Adobe Premiere.
Mastering Generally, this term is used interchangeably with “recording” (with reference to desktop production of CDs and DVDs), although it originally referred to the creation of a glass master for the mass production of CDs.
Matrix Decoding Creating multiple audio channels from a two-channel source.
Matroska Video and audio file formats which support OGG audio and variable framerate video. File extensions:

  • .mkv: video files
  • .mka: audio files (compatible with a number of compression formats: MP2, MP3, Vorbis, AAC, AC3, DTS and PCM)
  • .mks: subtitles
Matte The black bars used to change a screen’s ratio from standard TV (4:3) to widescreen (16:9).
Media Organized means of communicating information. With regard to video production, recordable media are blank tapes or discs.
Media Conversion Converting data from one type of media to another; for example, VHS to DVD.
MicroMV A Sony videotape format with extremely small cassettes: each is only the width of a couple of quarters, and holds 60 minutes of 12 Mbps MPEG-2 video.
Middle Area The unused area between layer 0 and layer 1 on dual-layer discs.
Mini DV A digital video format with both high resolution (up to 530 lines) and small size, allowing for smaller camcorders.
miniDVD (or cDVD) DVD video recorded on a CD-R or CD-RW. One of these discs will only hold about 15 minutes of DVD video, and not all DVD players will be able to play them.
Mixed-Mode Disc A CD with both computer data and audio tracks.
MJPEG Moving JPEG (or Motion JPEG). A moving image created by rapidly decompressing and displaying JPEG images. Unlike MPEG, no interframe coding is used.
MLP Meridian Lossless Packing. A lossless compression method for DVD-Audio (roughly 2:1) that removes redundancy from pulse-code modulation (PCM) audio signals. An MLP decoder can then perfectly re-create the signal.
MMC Multi-Media Command. A command set used by some disc recorders, telling the hardware how to interact with different types of media. Not all machines interpret MMCs the same way.
Mode 1 CD-ROM physical format.
Mode 2 CD-ROM XA physical format.
Mono Monaural. Sound from a single channel.
Motion Compensation and Prediction Describing the difference between consecutive video frames in terms of the where each section of the former frame has moved to.
Motion Estimation Finding optimal (or near-optimal) motion vectors.
Mount Loading a CD or DVD into the appropriate drive on a computer.
Mount Rainier A file system for optical discs that adds packet-writing capabilities to the Universal Disk Format, making rewriteable discs a better medium for temporary file storage than floppy discs.
MOV QuickTime content (file extension: .mov or .qt). A Mac-based file format that allows the viewing and manipulation of video, animation, 3D and virtual reality files.
MP3 MPEG-1 (or MPEG-2) Layer 3 audio encoding. A compressed audio format which has become an extremely popular method for storing, sharing and playing music and other audio content. Although it is a lossy format, it still produces near-CD-sound (at least to the human ear). MP3 files can be “ripped” from CD audio tracks, or converted into tracks that can be read by a CD player. There are a growing number of MP3 players on the market, allowing people to store thousands of songs in a small, skip-free device that can be taken anywhere.
MP3 ID3 Tag Identifying text stored at the end of an MP3 file, such as song name, artist, album title and year of release. An advanced version (Version 2) will be able to hold more information, such as graphics (for album covers) and song lyrics.
MP4 A multimedia “container” defined in the MPEG-4 standard (file extension: .mp4) that can combine media in different formats into one file. MP4s can handle multiple audio and video streams, variable bit/stream/sample rates, and even 3D graphics and interactive features.
MPA MPEG Audio elementary stream, either Layer 1 or Layer 2. Layer 2-only MPEG Audio is sometimes called MP2.
MPEG Moving Picture Experts Group. The name of the group which sets the various MPEG video compression standards.
MPEG Audio A group of MPEG standards for low bit-rate coding of audio files.
MPEG-1 A video compression method (6:1), which plays at 30 fps. The quality of the picture is low, with only one-fourth the resolution of analog TV.
MPEG-2 An extension of the MPEG-1 compression method, MPEG-2 is the encoding standard used for satellite TV and DVDs. MPEG-2 can handle widely varying bit rates, multichannel surround sound, and interlaced video.
MPEG-3 A proposed extension to MPEG-2, which was instead incorporated into MPEG-2. MPEG-3 is not the same as MP3!
MPEG-4 An encoding standard that combines digital television, interactive graphics and interactive multimedia content, creating interactive videos on CD-ROM/DVD and digital television.
MPEG-7 Multimedia Content Description Interface. An encoder which is not application-specific; it permits only some interpretation of multimedia content data. It is meant to support as broad a range of applications as possible.
MPEGInfoX Mac software that provides a user with information about an MPEG file.
mpegproperties Windows software that provides a user with information about an MPEG file.
MPlayerOSX A VCD/SVCD player for the Mac OS X.
MPV MPEG-1 or MPEG-2 Video elementary stream. Also called M1V (for MPEG-1) or M2V (for MPEG-2).
MSCDEX Microsoft DOS extensions for CD-ROM. Allows the DOS and Windows 3.x operating systems to recognize a CD-ROM disc.
Multichannel Surround Sound Audio systems with more than two channels, such as Dolby Digital or DTS.
Multi-Language A feature of DVDs where foreign-language tracks are included; the viewer can select which language they want the dialogue to be spoken in.
Multimedia Any combination of text, graphics, sounds, animation and video.
Multiple Audio Tracks All of the audio tracks stored on a DVD (up to nine); uses include foreign-language tracks, director’s commentary and isolated musical scores.
Multiple Video Tracks All of the video tracks stored on a DVD; uses include different camera angles, different credits or additional graphic content.
Multiplex (or Mux) Combining video and audio into a single file.
MultiRead A CD-ROM/DVD-ROM computer drive standard which allows the computer to read audio CDs, data CDs, CD-Rs and CD-RWs.
Multisession Adding data to a disc in more than one recording session. It is possible to link data from one recording session to a later session.
Multisystem Playback technology that can handle more than one video standard, like a VCR that can play both NTSC and PAL videos.
Multivolume A disc recorded in multiple sessions which are not linked. Each “volume” on the disc is read as though it were a separate disc.
Music Video A video presentation featuring the performance of a musical artist or group. MTV was the first channel to begin broadcasting music videos in 1981.
N
NA Numerical Aperture. A unitless measure of the light-gathering capacity of a laser pick-up device which determines resolution power and depth of field. It is calculated as

NA = n sin(α)

where

n = the refractive index of the lens immersion medium

α = the half-aperture angle

By definition, a vacuum has an NA of 1.0.

Native Resolution The original resolution of a video recording.
Navigation Data DVD-Video has five different types of navigation data which allow a user to jump to a particular location on the disc:

  • Video Manager Information (VMGI)
  • Video Title Set Information (VTSI)
  • Program Chain Information (PGCI)
  • Presentation Control Information (PCI)
  • Data Search Information (DSI)

Each piece of navigation data contains a block of information describing how it connects or interacts with other pieces of navigational data. For instance, a program chain (PGCI) can contain information that identifies which program chain to play next after it reaches the end of its play. A PGCI can also contain command instructions that control a DVD player’s behavior before and after the program chain plays.

Nero A Windows program for recording data and video to CDs/DVDs.
Noise Meaningless information added to a signal, either by the recording/transmission medium or by an encoding/decoding process. Digital signals are much less susceptible to noise than analog, although compression may still add noise to either.
NTSC National Television System Committee. The group which devised the TV/video broadcast standard for the United States in 1953. NTSC video has a vertical resolution of 525 lines and a display rate of 59.94 fields per second (29.97 frames per second; one frame being made of two interlaced fields).
NUON A processor chip designed by VM Labs that brings enhanced features to DVD players, such as the ability to play video games.

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