16:9 – widescreen aspect ratio (1.78:1) used in DVD and DTV; a close compromise to the 1.85:1 aspect ratio used in film.
4:3 – the aspect ratio (also expressed as 1.33:1) of a standard television screen.
AC-3 – see Dolby Digital.
activate – to execute the command associated with a button.
Album – the program on one side of a DVD-Audio disc; each album may contain up to nine Groups.
AMG – Audio Manager; see AMG/AOTT and AMG/AVTT.
AMG/AOTT (Audio Manager/Audio-only Title) – the content directory on a DVD-Audio disc that is used by smart Audio-only players.
AMG/AVTT (Audio Manager/Audio and Video Title) – the content directory on a DVD-Audio disc that is used by players that have video output (Audio-with-Video players and Universal players).
AMGM – Audio Manager Menu, the main visual menu for an AMG/AVTT DVD-Audio volume; the destination of the TITLE button on a DVD-Audio player remote.
anamorphic – a widescreen (16:9) image horizontally squeezed to fit into a 4:3 frame. When played back on a standard (4:3) TV, the image may be viewed in its anamorphic state, letterboxed, or pan/scan.
AOB – see Audio Object.
AOBS – see Audio Object Set.
API – applications programing interface.
aspect ratio – the relationship between the horizontal dimension and the vertical dimension of an image.
asset list – a complete list of the various audio, video, graphic, text, and subpicture elements included in a DVD title; prepared as part of the production planning process.
assets – the various audio, video, graphic, text, and subpicture elements included in a DVD title.
Audio Object (AOB) – the basic unit of DVD-Audio presentation data; made up of one or more Tracks (songs or compositions) of audio, optionally accompanied by still images and/or Real Time Text.
Audio Object Set (AOBS) – the collection of AOBs that make up the presentation data referenced by an audio title.
Audio Still Video (ASV) – the basic unit of graphics in DVD-Audio. An ASV is composed of an MPEG still, plus optional subpicture unit overlay (SPU), and highlight information (HLI).
Audio Still Video Unit (ASVU) – in DVD-Audio, a collection of up to 99 ASVs that is available for display over an ASVU range, which extends over one or more audio tracks. The total of all the images in an ASVU may not exceed 2 MB.
Audio Text Data – in DVD-Audio, text that is intended for the display of static information that is not synchronized to the audio program, including Album title, Group name, and Track title.
Audio Title (ATT) – the domain encompassing the logical structure of the main (non-menu) content on a DVD-Audio disc.
Audio-with-Video player – a DVD-Audio player that has video outputs; uses the AMG/AVTT content directory on DVD-Audio discs.
Audio_TS – the file directory on a DVD where DVD-Audio data is stored.
authoring – a media integration process in which a set of individual media elements (audio, video, graphics and text) are combined into a unified whole, and navigation between the various parts is defined.
auto-activate – a button state in which the command associated with the button is activated as soon as the button is selected, without the viewer having to press ENTER.
autoplay – an authoring parameter that commands the disc to begin playing a given program as soon as the disc is loaded into the player.
B-pictures – bi-directional pictures in MPEG-2; reconstructed by referring to information in both a previous and a subsequent frame.
background image – motion video or 24-bit colour still image that is used as the backdrop on menu screens.
bandwidth – the rate at which a given playback or transmission system is able to pass data (see data transfer rate); usually expressed in bits or bytes per second.
bit – the smallest unit of information in a digital file or stream.
Bit Budget™ – the allocation of a DVD’s overall data capacity and data bandwidth to the various audio, video, graphic, text, and subpicture elements included in the asset list.
bonding – the process of laminating together two 0.6-mm substrates to form a finished DVD.
Browseable – in DVD-Audio, a display mode for still images in which each image has a defined minimum and maximum on-screen duration, but the user is allowed to skip forward using the remote control.
browser – software that allows a computer to view HTML pages on the World Wide Web.
button highlight – the rectangular region of a menu screen that is reserved for each menu choice.
byte – a unit of data made up of 8 bits.
CBR – see Constant Bit-rate.
CD – see Compact Disc.
CD-ROM (Compact Disc-Read Only Memory) – a collection of formats used for storing and retrieving data on a CD, typically in a computer-hosted context.
cDVD – a variation of DVD developed by Sonic Solutions that allows a DVD-Video program to be written to CD-ROM and played back from a computer hosted CD-ROM drive using special player software.
Cell – a section of a VOB; the smallest unit of presentation data that may be addressed directly when navigating during branching or other interactivity.
chapter – a navigational marker allowing a PGC to go to a specific Cell in a VOB; typically used to allow direct access to individual scenes.
codec – the generic term for compression/decompression algorithms that are used to reduce the storage and transmission requirements of video, audio and graphics files.
colour-depth – in computer graphics, the total number of possible colours supported for display in a given image format or with a given computer and monitor. Usually given as the number of bits available to express the saturation value of each of the three component colours (red, green, blue) for each pixel (i.e. 8-bit, 24-bit, etc.).
Compact Disc – an optical medium for storage and playback of digital audio and data.
component video – a video system (analog or digital) in which the picture information is maintained as three components, such as RGB (red, green, blue).
composite video – a video system in which all the picture information (including sync pulse) is mixed into a single signal.
conforming – in video post-production, editing audio tracks to be in sync with a video master.
Constant Bit-rate (CBR) – a video encoding method in which bits are allocated evenly across the entire length of the program.
Content Scrambling System (CSS) – see encryption.
copy protection – technologies used to prevent the copying of analog signals or digital output streams from a DVD-Video or DVD-Audio disc.
CSS – see encryption.
data transfer rate – the rate at which digital data are retrieved from a storage medium or transmitted through a transmission medium. Usually expressed as either bits or bytes per second.
decoder – the hardware or software used to recreate a video or audio signal from an encoded stream.
Direct Stream Digital (DSD) – a digital audio encoding method in which the waveform is measured at a sampling rate of 2.8 MHz (2.8 million times per second), and changes in direction of the amplitude (rising or falling) are stored.
DirectShow – an API supporting MPEG-2 playback on computers running the Microsoft Windows operating system.
disc image – a complete set of files containing the logical and presentation data of a DVD volume, formatted in DVD’s UDF file system and ready to be output to a DVD master or DVD-R one-off.
DLT (Digital Linear Tape) – the master format normally used for DVD when the title will be replicated at a plant.
Dolby Digital (AC-3) – an audio codec developed by Dolby Laboratories using perceptual coding to deliver audio in low bandwidth settings. Playback support for Dolby Digital is mandated for all DVD players. In DVD, Dolby Digital bit-rates range from 192 kbps for mono/stereo program to 384–448 kbps for 5.1 channel surround sound.
double-sided – a disc, such as a DVD-10 or DVD-18, that has information moulded into both of its laminated polycarbonate substrates.
downmix – the combining of a multichannel audio mix into a stereo program.
DSD – see Direct Stream Digital.
DTS – an audio codec developed by Digital Theater Systems for delivering 5.1 channel surround sound in theatres and consumer electronics devices.
DTV – the digital television standard for the US, defined by the Advanced Television Systems Committee.
dual-layer – a method of constructing DVDs (DVD-9 and DVD-18) that allows a single disc image to extend over two data surfaces read from the same side of a disc, thereby nearly doubling the capacity of the side.
dummy PGC – a Program Chain that does not include a list of cells to play from a VOB. Used to group multiple commands together by using only the pre- and post-command areas. Dummy PGCs may also be used to move between Video Title Sets.
DVD Forum – A consortium of more than 100 member companies, including consumer electronics manufacturers, computer companies and content owners, which is responsible for defining and maintaining the DVD specification.
DVD navigator – a software module that allows DVD-Video titles to play back on computers.
DVD-5 – a DVD disc with a capacity of 4.7 GB; single-sided, single layer.
DVD-9 – a DVD disc with a capacity of 8.54 GB; single-sided, with dual layers.
DVD-10 – a DVD disc with a capacity of 9.4 GB; double-sided, with a single layer on each side.
DVD-14 – a DVD disc that is dual layer on one side and single layer on the other. DVD-14 is not part of the official DVD specification.
DVD-18 – a two-sided DVD disc with a capacity of 17.08 GB; dual layer on both sides.
DVD-Audio – a high-fidelity audio-centric format provided for in Book C of the DVD specification.
DVD-Audio player – a playback device for DVD-Audio discs; variations include simple Audio-only player, smart Audio-only player, and Universal player.
DVD-Audio zone – a directory (AUDIO_TS) on a DVD disc containing all of the data elements for playing back the disc’s DVD-Audio content.
DVD-Others zone – that portion of the file structure on a DVD disc that is not within the VIDEO_TS or AUDIO_TS directories.
DVD-Random Access Memory (DVD-RAM) – a rewriteable DVD format defined by Book E of the DVD specification.
DVD-Recordable (DVD-R) – a recordable, write-once DVD format defined by Book D of the DVD specification.
DVD-Rewritable (DVD-RW) – a rewriteable DVD format defined by Book F of the DVD specification.
DVD-ROM – a general-purpose data format provided for in Book A of the DVD specification. DVD-Video and DVD-Audio are specific applications that extend the basic DVD-ROM specification.
DVD-ROM drive – a computer-hosted reader for playback of DVDROM discs. With additional hardward and/or software, a computer with a DVD-ROM drive may also play DVD-Video and DVD-Audio content.
DVD-Video – a high-quality video-centric format provided for in Book B of the DVD specification.
DVD-Video player – a player that hooks to a television set and plays back DVD-Video specification discs.
DVD-Video zone – a directory (VIDEO_TS) on a DVD disc containing all of the data elements for playback of the disc’s DVD-Video content.
eDVD – a DVD-Video disc authored with Sonic Solutions technology that enables Web-connectivity. When an eDVD is played in a computer-hosted DVD-ROM drive, links embedded in the DVD-Video content enable navigation of content displayed in a browser.
elemental assets – the video, audio, graphics and subpicture files that are combined into VOBs during production of a DVD title.
encoder – the hardware or software used to convert a video or audio signal or file into a specific format; often involves use of an algorithm for reducing the amount of data.
encryption – a copy protection measure used in DVD in which data are scrambled to prevent DVD players from recreating a valid signal from an unauthorized copy of a DVD disc.
EQ (equalization) – changing the frequency content of an audio program through the use of filters that boost or cut in specific frequency ranges.
featurette – a short program included on a feature-film DVD as added-value content, generally explaining the making of the main feature or giving background related to the events depicted.
field – in interlaced video, one of two alternating sets of scan lines that combine to make a complete video frame. In DVD, video may be stored either as field-based video or as frame-based video. On playback, both types of video are output as field-based (interlaced) video for viewing on standard television monitors.
formatting – the creation of a set of files which complies with the DVD-Video or DVD-Audio format specification. Involves multiplexing presentation data (audio, video, subpictures) and incorporating the PGCs into the information areas of each volume’s managers.
frame – in video and film, a single complete picture; two fields of interlaced video.
General parameters (GPRMs) – memory locations used by the currently playing DVD program for basic computation or for storing values. Sixteen 16-bit memory locations are available. Examples of typical GPRM usage include remembering which segments of an interactive story have already been viewed, or keeping track of the number of lives a character has left in a game.
Gigabyte (GB) – used in relation to DVD, a Gigabyte equals one billion bytes, rather than the 10243 bytes definition used in the computing industry.
GOP (Group of Pictures) – in MPEG video, a sequence of pictures (frames) defined by a pattern of I-pictures, B-pictures and P-pictures.
GPRMs – see General parameters
Group – in DVD-Audio, a play list specifying the playback order of a number of audio Titles; a given Track may be referenced by more than one Group. There may be no more than 99 Tracks total within a single Group.
hDVD – an extension of the DVD-Video format, developed by Sonic Solutions, which allows the creation of DVD-Video titles using High Definition video. hDVDs may be played back from a computer-hosted DVD-ROM drive using special player software.
highlight – see button highlight.
hot spot – see button highlight.
HTML – Hypertext Markup Language, the format used by Web browsers to display Web pages.
hybrid title – a DVD with content stored outside the DVD-Video or DVD-Audio zones, which may be accessed by users with DVD-ROM drives.
I-pictures – in MPEG-2, pictures that are encoded using intra-frame compression only, and contain all the information needed to reconstruct an individual frame of video.
Index – a reference point to a portion of an audio track (Cell); there may be up to 99 Indices within a single track.
inter-frame compression – in MPEG video compression, a data-reduction technique in which only the information necessary to describe the differences between a series of adjacent video frames is retained. When the encoded material is played back, a decoder extrapolates from the stored information to re-create a complete set of discrete frames.
interlaced – video in which a complete frame is scanned in two passes (fields) of alternate lines (odd lines, even lines).
intra-frame compression – in MPEG video compression, a data-reduction technique in which the colour information within individual video frames is re-coded to express redundant information more efficiently. Depending on the degree of compression, adjacent colours that are similar to one another may be encoded as if they are the same colour.
inverse telecine – the removal of redundant fields introduced into NTSC video during the film-to-video (telecine) transfer process.
letterbox – a widescreen image shown in full on a 1.33:1 screen, with black borders along the top and bottom.
Linear PCM – see Pulse Code Modulation.
logical format – the structure used to organize the storage of data on a storage medium; the logical format of DVD is UDF.
Manager – the first directory that a DVD player reads to determine what content is present on a given disc.
menu – in DVD, a screen or succession of screens offering the viewer options for playback navigation or setup.
menu background – motion video or 24-bit colour still image that is used as the backdrop on menu screens.
Meridian Lossless Packing (MLP) – a lossless data reduction technique which allows PCM audio to be stored more efficiently without any loss of fidelity; mandated player support for MLP playback is part of the DVD-Audio specification.
metalizing – the application of the reflective coatings that allow the pits moulded into the surface of a DVD to be read by an optical pickup.
micro-UDF – a subset of the UDF file system (see Universal Disc Format) that includes additional constraints to facilitate use in an inexpensive playback device, such as a set-top player.
mixed density disc – a dual-layer DVD combining a conventional (CD-density) layer with a high-density DVD layer.
motion menu – a menu with a motion video background.
MLP – see Meridian Lossless Packing.
MPEG – Motion Picture Experts Group, an organization that defines encoding techniques for video and audio programs.
MPEG Audio – audio encoding algorithms defined by MPEG for low bitrate storage and transmission of stereo and multichannel (up to 7.1) program; may utilize variable bit-rate audio encoding.
MPEG-1 – a video compression scheme developed by MPEG and used in Video CD (White Book). Playback support is mandated for DVD players, but MPEG-2 is generally used on DVD discs.
MPEG-2 – a video compression scheme developed by MPEG and mandated in DVD players. MPEG-2 uses both intra-frame and inter-frame compression to store video more efficiently (reduce data redundancy) and, where necessary, to discard information (based on perceptual coding techniques) that is likely to have the least impact on image quality.
multi-angle – a DVD-Video feature allowing a single video stream to incorporate up to nine parallel video programs (which may or may not be different angles of the same scene).
multichannel – audio intended for playback over three or more speakers; see surround sound.
multiplex (MUX) – the interleaving of data from multiple elemental streams (i.e. video, audio, subpictures) into a single stream.
NLE – non-linear editing; computer-based video editing systems in which the data to be edited are stored on a random access medium (such as a hard-disk) rather than on a linear medium such as videotape.
NTSC – National Television Systems Committee, the organization which developed the standards used for analog television transmission in the US (also adopted in Japan, Canada and Korea). NTSC television uses 525 lines (480 of which are used for picture information) at frame rates of 30 fps (60 fields) for black-and-white and 29.97 fps for colour.
P-pictures – predictive pictures in MPEG-2; reconstructed based on the nearest previous I- or P-picture.
PAL – the Phase Alternate Line television standard used in Europe and various other regions throughout the world. PAL video normally uses 625 scan lines (576 lines of vertical picture information) at a frame rate of 25 fps (50 fields).
palette – in DVD, the set of 16 colours that is available for use in subpicture overlays in the current Program Chain.
pan/scan – a method of displaying widescreen content on a standard video monitor. A 4:3 viewing area is moved around over the original widescreen image to follow the most important action in the frame, while material on either side of this area is left out.
parental control – a system allowing the owner of a DVD-Video player to set the player to block playback of material beyond a given rating level.
PCM – see Pulse Code Modulation.
perceptual coding – an overall approach to data reduction algorithms for video and audio in which decisions about which data to discard are based on assumptions about human perception.
PGC – see Program Chain.
pit-density – the number of pits that can be moulded into the surface of an optical disc. DVD uses shorter pit lengths and tighter tracks to achieve a pit-density more than four times greater than CD.
pits – a series of tiny impressions moulded in a spiral track into the surface of a CD or a DVD. Binary code is represented by varying the length of the pits. Once the disc is coated with a reflective layer, the optical pickup of a playback device can read the difference in reflectivity between the pits and the surrounding land area.
pixel – a unit of measurement in computer graphics (the smallest individually addressable unit of area on the screen); an individual dot in a computer graphic image.
post-command – a command at the end of a Program Chain, commonly used for tasks such as linking directly to another PGC, or returning to a main menu.
pre-command – a command at the start of a Program Chain; sets a playback condition for the VOBs that follow, such as which audio stream will be played.
pre-processing – the use of a digital noise reducer or low-pass filter to reduce high-energy noise in the video signal prior to encoding.
Program Chain (PGC) – the basic logical unit of the DVD specification; a set of instructions determining the conditions, timing and order of the playback of VOBs and (in DVD-Audio only) AOBs. In DVD-Video, a PGC may include a pre-command, a list of cells to be played from the referenced VOB, and a post-command.
progressive scan – in video, the writing of each frame entirely in one pass (non-interlaced).
proofing – the previewing of a project during authoring to check that it plays back as intended.
PTT – Part of Title; see chapter point.
Pulse Code Modulation (PCM) – a digital audio encoding method in which the amplitude of a waveform is measured at regular intervals and converted into a binary code that is stored as a series of pulses. The resolution of a PCM system is a function of both the sample rate and the word-length (number of bits per sample).
Pure Audio disc – a DVD-Audio disc that includes only audio content (no graphics, text or video) and the SAMG content directory.
QuickTime – a software platform for synchronized playback of a variety of video, audio, still picture, animation and other file types on Mac OS and Windows computers.
random – in DVD-Audio, a display mode for still images in which the order is randomly determined by the player.
Real Time Text – in DVD-Audio, text that is stored on disc as part of the audio stream, and may be synchronized to audio playback; may be used for lyrics, libretto, and running liner notes.
regional coding – a hardware-coded identifier that indicates the region (out of six worldwide) in which a DVD player is to be sold. A DVD-Video title may be coded to allow playback only on machines from one or more regions.
replication – the mass production of optical discs using injection-moulding techniques.
reverse spiral – refers to the read direction of the second layer of a continuous-play dual-layer DVD. The first layer is read from the centre of the disc to the outside, at which point the read optics refocus onto the second layer and begin reading from the outside back in towards the middle.
RGB – the red-green-blue form of component video; commonly used for computer monitors.
rollover – to move a computer’s cursor over an on-screen button.
safe area – the portion of a video picture that will definitely be displayed on an NTSC television screen; excludes the outermost 5–10 per cent of the image on all sides.
safe colours – the range of colours that can be displayed by NTSC television, which has a more limited saturation range than the RGB video used in computer graphics.
SAMG – Simple Audio Manager; a mandatory content directory on DVD-Audio discs. SAMG is a sequential list of up to 314 tracks for linear, track-based navigation (similar to CD) on simple Audio-only players.
sample-rate – in digital audio, the number of times per second that the source waveform has been sampled (see Pulse Code Modulation).
SDDS – Sony Dynamic Digital Sound, an audio codec for delivering 7.1 channel surround sound in theatres and consumer electronics devices.
sDVD – a method developed by Sonic Solutions allowing DVD-Video material to be output in a data-reduced form for transmission over broadband networks including the Internet.
segment-based re-encoding – the ability of an encoding system to re-encode a portion of a given video program without having to re-encode the entire program.
select – to navigate to a button with the remote (or mouse).
sequential – in DVD-Audio, a display mode for still images in which the order is predetermined by the producer.
shuffle – in DVD-Audio, a display mode for still images in which the order is randomly determined by the player, but no image is repeated until every image has been shown.
simple Audio-only player – a DVD-Audio player that has no video output and uses the SAMG content directory, which supports only linear, track-based navigation of DVD-Audio discs.
slide show – in DVD-Video, a sequence of still video images pre-programed to advance automatically.
slideshow – in DVD-Audio, a display mode for still images in which each image is displayed for a predetermined amount of time.
smart Audio-only player – a DVD-Audio player that has no video output, but uses a disc’s AMG/AOTT content directory, supporting hierarchical navigation based on groups; may include an LCD display to show song titles and other text information such as lyrics.
SMART Content – System Managed Audio Resource Technique; a DVD-Audio feature allowing definition of the relative level, panning and phase to be applied to each channel of a multichannel mix if that mix is down-mixed to stereo. A SMART down-mix of a given program will only be played if a discrete 2-channel mix of that program has not been included on the disc.
still show – in DVD-Video, a sequence of still video images that may be advanced manually by the user.
storage capacity – the amount of data that can be stored on a given storage medium. The storage capacity of DVDs ranges from 4.7 GB to 17.08 GB.
storyboard – a set of rough visual mock-ups that are used to help define a program’s contents and plan production.
subpicture overlay – images that are generated by the DVD player on playback and appear on top of background video or still images. Used for subtitles and for highlights on menu screens.
substrate – in DVD, the plastic parts that are moulded during replication; a finished DVD is constructed from two 0.6-mm substrates bonded together.
Super Audio CD – a disc format proposed by Sony and Philips that is based on the same physical and logical structure as DVD but stores audio in the DSD format.
surround sound – audio playback configurations in which some of the channels are intended to be played back from the side or rear of the listener rather than only from the front. Common surround configurations include Lt/Rt (left, centre, right, and surround channels) and 5.1 (left, centre, right, left surround, right surround and low-frequency effects channels).
System parameters – memory locations used by a DVD player to remember default settings such as language, aspect ratio, and Parental Rating level. System parameters may be set either by the viewer or by a DVD title as it plays.
telecine – the process of transferring film to video.
Title – in DVD-Audio, a set of Tracks. The order of Title playback is defined by Groups (playlists).
Track – in DVD-Audio, a single audio program (i.e. a song or composition). Audio attributes such as channel configuration, sample-rate, and word-length may be changed on Track boundaries (players may mute during such attribute changes).
track – in DVD-Video, an audio or subtitle stream which accompanies a video stream.
UDF – see Universal Disc Format.
Universal Disc Format (UDF) – the file system used in DVD; designed specifically for use on replicated optical media.
Universal player – a player with the capabilities of both a DVD-Video player and an Audio-with-Video DVD-Audio player.
Variable Bit-rate (VBR) – a video encoding method in which more bits are allocated to complex, hard-to-encode segments of the program, and fewer to the rest, resulting in higher subjective playback quality at lower overall bit-rates.
VBR – see Variable Bit-rate.
Video Manager (VMG) – a master directory for the data elements on a DVD-Video disc.
Video Object (VOB) – the basic media file of DVD-Video presentation data; a multiplexed stream containing the video, audio, and subpicture material to be displayed on screen.
Video Object Set (VOBS) – the collection of VOBs which makes up the presentation data referenced by a Video Title.
Video Title (VTT) – a single video presentation; part of a Video Title Set.
Video Title Set (VTS) – the video, audio and graphical elements of each program on a DVD-Video disc. A VTS is made up of a VTS Menu (VTSM) and one or more Video Titles (VTT). All the video in a given VTS must be in the same aspect ratio.
Video_TS – the file directory on a DVD where DVD-Video data are stored.
VMGM – Video Manager Menu; the main menu for a DVD-Video volume; the destination of the TITLE button on a DVD-Video player remote.
VOB – see Video Object.
volume – the top level of organization on a DVD disc. A single-sided DVD (DVD-5 or DVD-9) contains a single DVD volume, while a double-sided disc (DVD-10 or DVD-18) is made up of two independent volumes.
VTS Menu (VTSM) – the menu for each VTS on a DVD-Video disc. VTSM is the destination of the MENU button on the player remote.
WebDVD – Microsoft’s approach to supporting Web-connectivity for DVD; uses the ActiveX-based Windows Media Player and requires a Windows 98 computer with DirectShow decoder and Internet Explorer 5 or higher.
WG-4 – the working group within the DVD Forum that developed the specifications for DVD-Audio.
widescreen – aspect ratios used in film (1.85:1, 2.35:1) and television (16:9) in which the horizontal screen dimension is significantly greater than the vertical.
workgroup – an approach to production system design in which a set of workstations, each optimized for specific tasks, is integrated into a network that facilitates the smooth progression of projects though the various stages of production.