B C D E F G H I J K L M N O P Q R S T U V W X Y Z
( now Dolby Digital)
Dolby Digital Surround Sound System. This is a digitally compressed
audio format characterized by its ability to offer up to 6 separate
or discrete digital audio channels. AC-3 is used for DVD-Video
titles in the NTSC format. Standard digital PCM data such as used
on CD would take up too much data on a DVD-Video hence the adoption
of a compressed audio format. AC-3 5.1 is the five surround sound
channels plus a 1/10 bandwidth channel to drive a sub-woofer.
When a 6-channel master is not available, an AC-3 2-channel is
used to compress stereo PCM for DVD-Video. PAL titles will use
MPEG2 audio compression standard.
(Audio Engineering Society/European Broadcasting Union) is the
name of a digital audio transfer standard. The AES and EBU developed
the specifications for the standard. The AES/EBU digital interface
is usually implemented using 3-PIN XLR connectors, the same type
connector used in a professional microphone. One cable carries
both left- and right-channel audio data to the receiving device.
As used in DVD, "artifacts" refer to "video artifacts." These
are unusual or unwanted effects caused by the technology and processes
used to display motion pictures. Examples are flicker, color shift,
loss of resolution, changes in aspect ratio, etc. Broadcast standards
such as NTSC and PAL have their own inherent artifacts which affect
the motion picture image. DVD, or more accurately MPEG coding/decoding,
can introduce its own characteristic artifacts, the most notable
of which is "blocking" or "pixelating" where insufficient data
describing a picture causes it to be represented in many discrete
blocks across the screen.
The process of taking data assets such as video, audio, and text,
and combining them into a DVD-Video or DVD-ROM compliant disc
image. The inputs to this process might consist of compressed
video files in MPEG2, compressed audio files in AC-3 and subtitles
as bitmap images; the output or end result of the authoring process
would typically be a DLT tape with a DVD disc-image file and DDP
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The amount of data that can be transferred or processed per unit
of time. In simple terms, bandwidth is like pipe size; a 1-inch
water hose has a higher bandwidth than an-inch hose since it can
pass more water in the same time.
(Digital Betacam, Betacam SP)
Widely-used component digital video formats suitable for Digital
Video Compression work. Each has separate and different PAL and
A technical term used to describe how a reading laser will be
affected by the molded stresses and composition of an optical
disc. DVD discs are generally made of polycarbonate, which is
prone to taking up "stresses" during the injection molding process.
The laser light is "retarded" by non-ideal polycarbonate polymer
orientation and this has a bearing on the readout characteristics
of a DVD disc.
An image consisting of an array of pixels (picture-cells) that
can be displayed on a computer monitor having color/brightness
Testing / Bit-to-Bit Test
An automated data verification between a replica DVD disc and
the DLT Master tape used to create the Master disc.
The value of a pixel along the black-white axis.
- Constant Bit-Rate
This type of compressed video signal uses the same amount of data
to describe the video signal regardless of complexity. This is
standard MPEG technology used on satellite broadcasts and the
like where bandwidth or storage capacity is less of a problem.
CBR will most likely be used for short programs on DVD where a
higher bit-rate can be allocated to the entire program thereby
making the compression process automatic.
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Compact Disc: a 120mm (approx. 5") disc used to store optical,
machine-readable, digital data that can be accessed with a laser-based
reader such as a CD player.
Compact Disc Read-Only Memory: a compact disc used for computer
data and applications that cannot be modified and can be accessed
with a CD-ROM drive. See CD.
Twenty DVD replica discs as a sample Test Pressing for clients
to check the authoring and compression of their DVD projects.
Cost includes a full Mastering charge and QC verification of disc
data to customer-supplied Master. This is thought to be an essential
service until DVD-R technology arrives.
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A software driver used to compress and decompress video originally
digitized from an analog source. Literally "COmpression DECompression."
Any of several means of specifying colors according to their individual
components. See RGB, YUV.
A video signal format that separates chrominance and luminance
into two waveforms. See S video. Compare composite video. Component
video (e.g., D1) is the preferred format for video compression
A video signal format that includes all the visual information
in one waveform, including chrominance, luminance, blanking pedestal,
field, line, color sync pulses and field equalizing pulses. Compare
component video. D2 is an example of this. For video compression
work composite video source formats are often transferred to a
component video source format.
The process of converting video and audio data into a more compact
form for storage or transmission. Compare decompress.
The range between the darkest tone and the lightest tone in an
"Content Scramble System." The officially licensed DVD-Video digital
encryption scheme. CSS is applied during Glass mastering such
that the data on the DLT Master is scrambled and the final discs
are encrypted. Only a CSS-licensed DVD player can unscramble the
See pit-art. A pit-art design created from customer e-file image.
Involves a CD Mastering process to create the pit-art stamper.
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The speed of a data transfer process, usually expressed in kilobytes
(thousands of bytes) per second. CD-ROM drives expressed as 10X
drives are designed to have a data rate 10 times that of a standard
An industry standard component video digital video standard. The
D1 format is designed to carry PAL and NTSC programs plus PCM
audio. A D1 VTR can record either a PAL or NTSC program- they
are two different things. A D1 conforms to CCIR-601 and is a world
standard for high resolution digital video editing. D1 masters
are housed in large format cassettes. D1 is the preferred master
format for DVD-Video due to its being a component video format
and its high resolution.
A digital video standard. D2 is composite video and PCM audio.
Less suitable for DVD-Video due to being composite.
Disc Description Protocol. A small computer file or files describing
data to be Mastered onto an optical disc. This standard was developed
by Doug Carson and Associates and later adopted as an ANSI standard.
DVD Master Tapes on DLT feature a disc image consisting of the
data required to be placed on the DVD disc; the DLT may also contain
DDP files instructing the Laser Beam Recorder Data Formatter how
to process the data, for example, how to make the disc a DVD-Video
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2.0 DLT Master
A de facto standard for authored DVD Master images supplied to
glass mastering houses. The authoring system produces a tape with
three files: DDPID (see DDP) , CONTROL.DAT with manufacturing
information, and MAIN.DAT the main program. These Masters work
directly in a glass mastering machine with no pre-mastering at
the disc plant needed.
The process of decompressing a video clip and then converting
its color space from YUV to RGB. See decompress, RGB, YUV. Compare
The process of converting video and audio data from its compact
form back into its original form in order to play it. Compare
A frame containing only the data that has changed since the last
frame. Delta frames are an efficient means of compressing image
data. Compare key frame.
The process of turning an analog signal into digital data.
A video signal represented by computer-readable binary numbers
that describe colors and brightness levels.
Digital Linear Tape. A square-shaped tape used as a master tape
for DVD. It can hold 10-20 Gigabytes (or more for newer generations
of DLT) and can be used directly in mastering. The DLT system
is available at various data capacities and densities. Media designated
"Compact Tape Type III" and "Compact Tape Type IV" is commonly
compatible with DVD Authoring and Mastering systems.
The correct name for AC-3. See AC-3.
An acronym for Digital Versatile Disc, a new optical-disc technology
developed by the DVD Consortium, a collection of 10 companies
who contributed to the DVD standard and specification. There are
five specified DVD disc varieties: DVD-ROM, DVD-Video, DVD-Audio,
DVD-R (recordable), DVD-RAM (eraseable).
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A single-sided, single-layer DVD capable of holding 4.7GB of data.
Double-sided, single-layer DVD capable of holding 9.4GB of data.
Single-sided, dual-layer DVD holding 8.5GB of data. This unique
format allows both molded DVD data halves to be read from the
same side of the disc by using a clear bonding agent, a semi-reflective
metal layer on the first data disc, and by adjusting the focus
point of the player to read two layers.
Dual-layer, dual-side. Capacity 17GB of data.
A pre-recorded DVD disc conforming to the yet-to-be-released Book
C or the Audio Application specification in the DVD Audio specification.
A pre-recorded DVD disc conforming to the DVD File system and
specification but not to the DVD-Video or DVD-Audio specified
A pre-recorded DVD disc conforming to Book B or the Video Application
specification in the DVD Video specification.
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DVD disc masters are authored and created as a hard disc image.
DVD emulation software programs are designed to access the hard
disc image under the same conditions that a DVD-Video player accesses
the final DVD disc image. The emulator copies the functions of
a DVD-Video player to ensure the authored master image is compatible
with the DVD specification and that the resulting discs will be
compatible with DVD-Video players.
In the context of digital video and MPEG2, the process of converting
the color space of a video clip from a full-bandwidth source to
a compressed MPEG2 file.
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One half of a video frame, consisting of every other row (scan
line). See frame, interlacing.
Warner/Ivy Hill "Flip" or "Snapper Box" DVD-Video packaging configuration
with Home Video form factor.
The system on a glass mastering laser beam recorder that takes
the raw program data on the DLT master tape and formats it to
the DVD specification for creating the glass disc master.
One video or film image in a clip. Film is shot at 24 frames per
second. PAL TV is viewed at 25fps and NTSC at 30fps.
The number of frames per second at which a video clip is displayed.
Video that plays at thirty frames per second (NTSC) or 25 frames
per second (PAL).
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See pit-art. Discs can be printed with title and catalog number
information in plain black text for identification. This option
removes the custom pit-art mastering process.
Literally a billion bytes. A Gigabyte in DVD nomenclature represents
exactly 1 billion bytes of data (one byte being 8 binary bits).
In some computer references a Gigabyte is referred to as 1024*1024*1024
bytes or 1.074 billion bytes.
The initial formation of the 120mm DVD disc image from the DLT
master tape. A glass master is an extremely fragile part in which
the DVD disc image exists in a sub-micron film of "photoresist"
material similar to the material used in the manufacture of integrated
circuits/silicon chips. See LBR.
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A process in which DVD disc halves are bonded using a glue which
is heated and allowed to harden after assembly. A well-established
technology used for Laserdisc and MO.
The process of drawing a frame by alternately drawing the rows
of each field, creating the illusion that the image is being redrawn
twice as often as it actually is. See field. This is a non-ideal
artifact of both PAL and NTSC broadcast systems, e.g., an NTSC
broadcast, although thought of as 30 frames per second, is actually
made up of 60 half-frames displayed one after the other per second;
each half-frame is consecutive black/video lines that interlace
to complete full frames. The alternative is progressive scan where
only complete frames are drawn on the screen; this is used on
computer monitors, HDTV, and in most cases where high quality
is important and the application is not tied to an interlaced
See Telecine process.
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Joint Photographic Expert Group: a standard for compressing single
images with high quality. Motion-JPEG is a way of expressing moving
images using this technology.
The standard plastic case used for the majority of audio CDs.
This term is used throughout the signal processing world and can
refer to many different problems in audio and video alone. In
DVD manufacturing, jitter relates to the fidelity of the disc
and player's data signal to the clock signal in the player. The
DVD and CD technology relies on the disc and player producing
data at discrete timing intervals in relation to the player clock.
Jitter is a true measure of manufactured disc quality. Low jitter
implies that the pits on a DVD disc are consistent in length and
allow the player to deliver data close to the system clock pulses
thereby minimizing the chance of misreading data.
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A VHS form-factor packaging configuration for DVD.
(Laser Beam Recorder)
The machine that creates the DVD disc master on a disc master.
The DLT master tape is the input to this machine. The glass master
that is made is the master image of the DVD disc.
The component of a video signal that includes information about
its brightness. See brightness. Compare chrominance.
A publicly traded US company with an analogue copy protection
technology for PAL and NTSC video signals. This is widely used
on VHS media and works by maladjusting the recording circuitry
in a VHS recorder such that the copied program is unwatchable.
Macrovision exists on VHS media but is applied by the hardware
for DVD after being instructed by the disc. For DVD (NTSC) Macrovision
comes in three flavors, AGC (Automatic Gain Control ? as VHS),
2-line, and 4-line color stripe.
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- (Megabits per second)
A mnemonic to express the amount of binary 1s and 0s being used
to express a digital data signal. The 133-minute video capacity
of a DVD which is often quoted is derived from assuming that the
video stream needs an average of 3.5Mbps to describe it. The average
Mbps required for the individual video, audio, and subtitle assets
determines ultimate runtime since the "bit capacity" of a disc
An inverse master image of a DVD disc that is used to create stampers.
A mother is a 9" nickel plate with a DVD disc image in the center.
Mothers are thin nickel electroforming plates used to grow stampers
in an electroforming or electroplating process. See Stamper.
Motion Picture Expert Group: a standard for compressing motion
pictures. MPEG1 and MPEG2 are two different standards catering
to digital video on CD and DVD respectively. MPEG1 is used on
VideoCD and CDI as a sub-VHS quality video distribution medium.
MPEG2 and DVD offer better-than-laserdisc quality and twice the
runtime per disc.
Compressed audio in stereo, six, or eight channel form for use
on DVD projects. PCM or MPEG stereo audio is mandated in PAL countries
for DVD. Multi-channel MPEG2 audio is optional worldwide.
Information that combines some or all of text, still images, sound,
animation, and video.
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The process of accessing the features of a DVD-Video disc using
the specified commands built into the DVD-Video specification.
See Titles and Chapters.
National Television Systems Committee: a committee of the Electronic
Industries Association that prepared the standards for commercial
television broadcasting in the United States, Canada, Japan, and
parts of Central and South America.
A color television format having 525 scan lines (rows) of resolution
at thirty frames per second (30 Hz). See NTSC. Compare PAL format.
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Phase Alteration Line: the standard for commercial television
broadcasting in most of Europe, Australia, parts of Central and
South America, and other countries.
A color television format having 625 scan lines (rows) of resolution
at 25 frames per second (25 Hz). See PAL. Compare NTSC format.
A look-up table of 256 color values.
Pulse-code-modulated audio. This is the uncompressed native digital
audio commonly used on the Video master tapes. It is often 16-bit
48kHz stereo which is 1.536Mbps or nearly half the bandwidth of
a typical VBR MPEG2 video stream. For this reason, PCM audio is
usually compressed to 2-channel AC-3 or MPEG audio in NTSC and
PAL countries respectively.
A decorative treatment for a DVD-5 dummy or top disc. A stamper
is created with mirrored areas defining a graphic image in a regular
CD pit-pattern. Customer supplies a black-on-white e-file image
preferably 300dpi plus.
Picture element (lit. picture-cell): the smallest independently
accessible unit of a digital image.
The number of bits of color information per pixel. A system using
eight bits per pixel can display 256 (28) colors. A system using
16 bits per pixel can display 65,536 (216) colors. A system using
24 bits per pixel can display over 16.7 million colors. Twenty-four-bit
color is often called true color because the human eye can distinguish
among approximately six million different colors, fewer than are
available in a 24-bit color system.
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A provision in the DVD specifications such that DVD players can
be hard-coded to accept DVD discs that are authored and encoded
for use in one of six designated world regions. Legislation will
exist to ensure that only regionally-coded players are produced.
Therefore when a DVD disc is manufactured, a region code is applied
at the authoring stage such that the final disc will play only
on those players distributed in the designated world region. This
technique was developed to enable motion picture companies to
release movies at different times in different regions.
regions (also called locales or zones) have been defined. Each
one is assigned a number:
The width and height of the video window, in pixels.
In DVD context, see Sandwich Print.
A color model used chiefly for computer displays in which colors
are specified according to their red, green, and blue components.
See component video.
The amount of gray, as opposed to hue, in a color-the intensity
of the hue. See hue.
DVD discs may be printed on the bonded surface prior to bonding
such that the printed image is viewed through the polycarbonate
and appears wet or extremely glossy. Only possible on DVD-5. Also
known as reverse-, wetlook-print.
(Serial Digital Interface) is a standard for digital video transmission
over coaxial cable. The most common data speed is 270 megabits
per second (Mbps). However, speeds of up to 540 Mbps are theoretically
possible. Standard 75-ohm cable is used. This is the same type
of coaxial cable used in most home television installations. The
SDI standard uses data words that are 8 or 10 bits in length.
Signals are uncompressed and are self-synchronizing between the
transmitter and receiver. Most errors caused by noise or interference
can be detected, and the lost data recovered by means of a specialized
code called the Hamming code. A signal in SDI can contain up to
four independent digital audio signals along with the video signal.
A 6" Nickel DVD disc master used as an insert in the DVD injection
molding process. Individual disc replicas are "pressed" off a
stamper during injection molding. The clear discs produced take
up the image of the stamper which is the DVD disc image created
during glass mastering.
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The process of creating a video master from a film master including
the step up from 24 film frames per second to 30 NTSC video frames
per second. Inverse telecine deals with retracing back to 24fps
to reduce the amount of digital compression work needed.
A measure of the flatness of a DVD disc. A critical quality parameter
for DVD; tilt defines at what angle the reading laser of the player
will return to the players detector to read the data. A non-flat
disc will cause the reading laser to stray away from the reading
detector and for information to be lost.
The DVD-Video specification allows video programs to be split
up into titles and chapters. This allows a two-level "directory"
structure. For example, a DVD-Video disc may contain three sporting
events; each event may be designated as a separate title. Each
period in the individual sporting event or title may be designated
a chapter. DVD-Video allows the creation of menus to access both
titles and the individual chapters in the title.
A VHS form-factor DVD packaging configuration.
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A process in which the two halves of a DVD are bonded together
with a bonding agent activated or cured by ultra-violet light.
Radical UV bonding utilizes a clear bonding agent and has applications
with all DVD formats; the bond is cured after assembly. Cationic
UV bonding features an opaque bonding agent that restricts its
use to single-layer DVD applications; curing is begun prior to
assembly and takes hours to reach final strength.
A feature of DVD allowing the authoring facility to allocate a
video compression bit-rate that varies with picture complexity.
Still scenes require a lower data rate or bit-rate to describe
the video than scenes with a great deal of action.
Title Set (VTS)
A term used for DVD Video to denote a set of .VOB files which
make up a title. One DVD-Video disc may have multiple titles or
title sets on it.
( .VOB or "video object")
The file format and extension specified for DVD-Video containing
the MPEG2 video, AC3 audio and navigation commands. A DVD-Video
title must have .VOB files in a directory called Video_ts. Associated
files are extension .bup, .ifo.
See Sandwich Print.
color model used chiefly for video signals in which colors are
specified according to their luminance - the Y component, and
their hue and saturation - the U and V components. See hue, luminance,
saturation. Compare RGB.
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