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Glossary:
D/A - DVDA
Glossary of CD and DVD related
technical terms and abbreviations in alphabetical order. |
D/A: Digital to Analogue
D-characters: The character set used in ISO 9660 filenames, consisting
of 'A' to 'Z', '0' to '9', and '_'.
DA-88 & DA-98: Tascam 8-channel digital audio tape drive used for
storing multi-channel audio for DVD.
DAC: Digital to Analogue Converter
DAO: Disc At Once recording. Refers to the ability of certain CD-Recorders to record a
CD-R or CD-RW disc in one continuous operation. This is necessary to
avoid glitches when playing recordable audio discs. (cf Track at Once).
 DARCC:
Deluxe Anti-piracy ROM Content Checker is professional automatic
media content checking software for media replication companies that
includes an extensive set of tools to increase effectiveness in
anti-piracy and software license compliance (see
www.darcc.net).
DAT: Digital Audio Tape, used to record audio in digital form at
sampling rates from 32kb/s to 48kb/s. Can be used to master compact
discs from. A data version (DDS) is also available.
 DataPlay: A new optical disc format comprising a 32 mm diameter disc in
a caddy that can hold 250 MB of data per side and will be available by
the end of 2001 in pre-recordable and recordable versions for music,
digital cameras and many more applications. The pre-recorded music
versions will include copy protection. (See www.dataplay.com)
Data Fork: The part of a Macintosh HFS file containing the actual data.
DCT: Discrete Cosine Transform used in intra-encoding JPEG and MPEG
frames. DCT coding encodes a block of 8 x 8 pixels at a time
transforming the pixels from the spatial domain to the frequency domain.
DDCD: Double Density CD, a new version of the CD specification offering
nearly twice the capacity of a standard CD by reducing the pit length
and track pitch and making the modulation and error correction more
efficient.
DDP: Disc Description Protocol, a standard for files accompanying CD and
DVD data for glass mastering, which identifies and describes collections
of data that will be recorded onto a compact disc (CD) or digital
versatile disc (DVD). DDP allows for automated transfer of data from
data publishers to disc manufacturers. DDP is the de facto standard in
the DVD industry for delivering disc image data to the replication plant
for manufacturing. (See www.dcainc.com).
DDS: Version of DAT used for storing computer data. Four types (DDS1,
DDS2, DDS3 and DDS4) exist.
Decompression: To convert a compressed file or signal back into the
original data before it was compressed.
DEG: See DVD Entertainment Group
DEGE: DVD Entertainment Group Europe, an organisation set up in
2002 to represent the various DVD Committees and other national DVD
organisations in Europe.
Delta Frame: Also called Difference Frame in a compressed digital video
sequence. Contains only the pixels different from the preceding frame.
DirectShow: Part of Microsoft's 32-bit API (DirectX) with provision
for playing DVD-Video VOB files, ie containing MPEG-2 video, audio and
navigation. DirectShow was called ActiveMovie and replaces MCI.
Disc: With a 'c' refers to CD, DVD, MiniDiscs and Laserdiscs.
Disc At Once: Refers to the ability of certain CD-Recorders to record a
CD-R or CD-RW disc in one continuous operation. This is necessary to
avoid glitches when playing recordable audio discs. (cf Track at Once).
Disk: With a 'k' refers to magnetic and magneto-optical disks (except
MiniDisc).
Dithering: The action of smoothing an image for example to smooth the
transition between two areas of different colours by adding a grainy
effect. DivX: A video distribution technology based on MPEG-4
video and MP3 audio for downloading video via the Internet and playing
in Windows Media Player.
Divx: An alternative but discontinued DVD-Video format from
Digital Video Express and Circuit City allowing discs to be rented, then
thrown away or kept. By using extra layers of encryption the discs
become unplayable after 48 hours, but this could be extended at any time
by making a financial transaction via a modem built into the DIVX
player. DIVX players will also play normal DVD-Video discs and were
launched in the USA in mid 1998. DVD-Video players will not play DIVX
discs.
DLT: Digital Linear Tape, the tape format used to transfer pre-mastered
DVD data for glass mastering.
Dolby Digital: Formerly called Dolby AC-3, is the 5.1 channel surround
sound audio compression format developed by Dolby and used on DVD-Video
discs.
Down-mix: The conversion of multi-channel audio to, for example, stereo
audio. The DVD-Audio specification allows coefficients to be stored on
disc to ensure that down-mixing results in the best quality stereo
output. DRM: Digital Rights Management,
which is a technology for the secure distribution of digital media
files, such as audio and video, via physical media or the Internet. DRM
technology includes rules for the use, eg re-distribution, of the
content. DRM software in appropriate players will play the audio or
video according to these rules. DRM is being added to copy protection
systems to add further features while controlling the copying of the
content.
DSD: Direct Stream Digital, an audio encoding format developed by Sony
and Philips for Super Audio CD, their proposed DVD-Audio format.
DSP: Digital Signal Processor, a programmable integrated circuit for
carrying out fast processing of a range of tasks such as audio or video
decoding.
DST: Direct Stream Transfer, a method of losslessly compressing
DSD audio so that a full 6 channels of audio can be stored on a SACD
disc.
DTLA: Digital Transmission Licensing Administrator for protecting
content on DVD discs etc.
DTS: Digital Theater System, the multi-channel audio coding used in
cinemas and also on some DVD-Video discs. DVD: A 'compact disc'
that contains 7 times as much data as a CD on each of up to 4
layers. Originally Digital Video Disc
then Digital Versatile Disc but officially is just DVD.
DVD-10: A double-sided pre-recorded DVD disc format, with a capacity of
9.4 GB.
DVD-14: A double-sided pre-recorded DVD disc format, with one dual layer
side and one single layer side offering a capacity of 13.2 GB, yet to
become available commercially.
DVD-18: A double-sided, dual layer pre-recorded DVD disc format, with a
capacity of 17.1 GB, currently used for a very small percentage of discs
available.
DVD-5: A single-sided, single layer pre-recorded DVD disc format, with a
capacity of 4.7 GB.
DVD-9: A single-sided, dual layer pre-recorded DVD disc format, with a
capacity of 8.5 GB. DVD-Audio: A pre-recorded DVD format
intended to carry high quality audio data plus optional images, text,
video and menus. The format was defined in 1999 and players and discs
appeared from late 2000. (See
DVD-Audio for more information.) DVD Books: The
specifications for all DVD disc formats. There are currently 12 Books
including DVD-Video, DVD-Audio, DVD-ROM, DVD-R, DVD-RW etc. The
DVD Books are available from the DVD FLLC. DVD CCA: DVD
Copy Control Association (www.dvdcca.org),
the organisation responsible for licensing CSS (Content Scramble System)
to manufacturers of DVD hardware, discs and related products.
DVD Committee: A UK committee comprising studios, hardware
manufacturers, authoring studios and replicators set up by the BVA to
promote the DVD-Video format in the UK. It has now added the DVD-Audio
format to its remit and has changed its name to the UK DVD Entertainment
Group.
DVD Entertainment Group: Formerly called the DVD-Video group, this
US-based organisation's mission is to market and promote consumer
awareness of the benefits of DVD-Video, DVD-Audio and DVD-ROM based
games, and to provide updated information to the media and the retail
trade about DVD-Video and DVD-Audio players, movies and music videos.
(See www.dvdinformation.com).
A European counterpart has recently been setup, based in London.
DVD FLLC: The DVD Format/Logo Licensing Corp, which licenses the DVD
Format and Logos to hardware manufacturers and replicators. The DVD FLLC
was established in April 2000 and is based in Tokyo (see
www.dvdfllc.co.jp).
DVD Forum: The organisation that comprises the ten original DVD
Consortium companies who developed the DVD formats plus other companies
involved in DVD. There are now over 230 members. The original 10 member
Steering Committee has been increased to 17. More information is
available from their website, www.dvdforum.org.
DVD-Multi: A new initiative actively supported by the DVD Forum aimed at
improving interoperability so that any DVD disc can play on any
DVD-Multi compliant player. However this does not necessarily imply that
individual files can be interpreted or played by the player.
DVD-ROM: The basic pre-recorded DVD disc, which supports DVD-Audio and
DVD-Video formats. Also used to describe other DVD formats not defined
in the DVD specifications including PC/Mac applications and DVD based
games consoles etc.
DVD-R: A recordable write-once DVD format, with a capacity of 3.95 GB
(first generation) or 4.7GB per side. There are two versions, Authoring
version with no copy protection and General version (for consumer use)
with copy protection (CPRM) and no CSS capability (which mean these
discs cannot be used to copy CSS protected discs).
DVD-RAM: A re-writable DVD, with capacities of 2.6 GB (first generation)
or 4.7 GB (second generation) per side.
DVD-RW: A re-writable DVD with a capacity of 4.7 GB per side. The DVD-RW
is an alternative to the DVD-RAM, which supports fewer re-write cycles
than DVD-RAM but is claimed to be more compatible with DVD-ROM drives.
DVD+R: A recordable write-once format, developed by Philips and
Sony but not recognised by the DVD Forum.
DVD+RW: A re-writable 12 cm optical disc with a capacity of 4.7GB per
side developed by Philips and Pioneer as an alternative to DVD-RAM. It
is claimed to offer almost total compatibility with existing players,
but is not an official DVD format.
DVD-Video: A pre-recorded DVD format capable of carrying 133 minutes of
high quality video (on a DVD-5) with multi-channel audio in up to 3
languages plus subtitles and menus to provide user interactivity. Other
features include multiple camera angles, parental lock and random
access. See DVD-Video for
more information.
DVD-VR: DVD Video Recording, a specification from the DVD Forum
for recording digital video on DVD media, that is not compatible with
DVD-Video but allows advanced editing facilities.
DVDA: DVD Association, formed in June 1999 by the IDMA as a sister
organisation. The DVDA is international in scope serving a membership
that spans from North America, to Europe and Asia. Their website is www.dvda.org.
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