DVD Terminology
DVD -- Digital Versatile Disc most commonly referred to as Digital Video Disc made by gluing two half CD thickness discs back to back. Has much greater capacity than CD and comes in various flavours as detailed below.
DVD-5-- Single-sided DVD disc format, with a storage capacity of 4.7GB. Approx 133mins.
DVD-9 -- Single-sided Dual-layer DVD disc format, with a storage capacity of 8.5GB. Approx 240mins.
DVD-10-- Double-sided DVD disc format, with a storage capacity of 9.4GB. Approx 133mins per side.
DVD-18 -- Double-sided Dual-layer DVD disc format, with a storage capacity of 17GB. Very rarely used as only a few facilities can make them.
DVD-ROM -- DVD Read-Only Memory. The computer-readable content on a DVD disc. Sometimes combined with DVD-Video for extra content to use on a computer. Also used for transporting large MPEG files that have not been authored into DVD-Video.
DVD-R -- DVD Recordable write-once format developed by the DVD Forum. Because the data cannot be erased, the DVD-R is useful for making permanent backups. Recordable discs are more compatible with set-top DVD players than rewritable discs
DVD+R -- Alternate DVD Recordable write-once format developed by the DVD+RW Alliance.
DVD-RW -- DVD ReWritable. The DVD Forum-defined, re-recordable DVD format. Like CD-RW, rewritable discs can be reused, but are more expensive than recordable, and are less compatible with set-top players.
DVD+RW -- Alternate DVD ReWritable format developed by the DVD+RW Alliance. Intended to replace the capabilities of DVD-RW and DVD-RAM and also provide higher compatibility with set-top players.
DVD-RAM -- DVD-Random Access Memory. The DVD Forum-defined, random-access DVD data format. Designed for data storage applications, with the ability to be randomly accessed like a hard disk, and with built-in error correction and defect management. Comes as either a bare disc or in a cartridge which can be single or double sided. Used as a ReWritable disc in Panasonic set top recorders and cameras.
DVD-Video -- Digital Video Disc. The variety of DVD most commonly assumed by the term DVD. Contains MPEG2 compressed movie file(s) in a special format designed for playback in set top DVD players. As part of this formatting the movie files are broken into parts no greater than 1GB and accompanied by indexing and menu files. This process is referred to as authoring. Nominal maximum duration is set at 133 mins for a DVD-5 but this can be exceeded with a sacrifice of some resolution.
CD Terminology
CD -- Compact Disc Nominally a 120mm diameter plastic disc 1.2mm thick with data either burnt or imprinted on it under a reflective layer and read by a laser shining through the disc. Originally had a storage capacity of 650MB (74mins audio) but now commonly with a capacity of 700MB (80mins audio) Comes in various flavours as detailed below.
CD-Audio -- This is the common audio CD which contains uncompressed audio sampled at 44.1kHz and has a maximum duration of 80mins. The content is formatted a such a way that the tracks are not directly accessible on a computer drive but are suitable for audio CD players.
CD-ROM -- CD-Read Only Memory. A CD disc containing computer-readable content with a nominal maximum capacity of 700MB.
Mixed Mode-CD -- A CD containing elements of both CD-Audio and CD-ROM so that it can be used in both an audio CD player and a computer.
Video-CD -- A CD containing an MPEG1 compressed movie file in a special format designed for playback in set top Video-CD and DVD players. Common in Asia but rarely found in New Zealand. An MPEG1 file on a CD does not have to be a Video-CD.
CD-R -- CD Recordablewrite-once format for burning discs in a computer drive. Because the data cannot be erased, the CD-R is useful for making permanent backups.
CD-RW -- CD ReWritable. The re-recordable CD format. Discs can be reused, but are more expensive than recordable, and are less compatible with set-top players.
Video and Capturing Terminology
Capturing -- The process of converting the video content to compliant MPEG files. Video Distributors use hardware capture cards which give superior results to software rendering.
MPEG1 -- This is the compression standard defined by the Moving Picture Experts Group for Video-CD and also used on CD-ROM for Windows Media Player playback. The resolution is 352 x 288 and data rate is 1-1.8MB/sec giving between 55 and 70 mins on a CD. Quality is only really suited to playback in a computer window.
MPEG2 -- This is the compression standard defined by the Moving Picture Experts Group for DVD. The resolution is 720 x 576 (PAL)and data rate is 4-8MB/sec giving between 70 and 140 mins on a CD. For longer durations up to 180mins a reduced resolution of 352 x 576 (PAL)and a data rate of 3MB/sec is available. Corresponding NTSC resolutions are 720 x 480 and 352 x 240.
PAL -- The television standard used in New Zealand, Australia, UK and most of Europe. PAL DVD's will not work with most DVD players and TV sets in USA.
NTSC -- The television standard used in USA, Japan, and some other countries. . NTSC DVD's will play in virtually any country due to the reason that most modern DVD players and TV sets in PAL countries are multi-standard. An NTSC DVD is the nearest thing to a universal DVD provided it does not have regional coding.
Frame Grab -- This is a single video frame from a video clip which is saved as a 720 x 576 picture in .bmp or .jpg format. This can be used as a menu background if required.
Aspect Ratio -- The proportion of width to height of a video image on a DVD is usually referenced to the height which is 1 unit. Most DVD movies are widescreen with a typical aspect ratio of 1.85:1, and this represents an image that is 1.85 units wide and 1 unit high, but some have an aspect ratio of as much as 2.35:1. The aspect ratio of a standard television is 1.33:1 and this is often expressed as 4:3. The aspect ratio of a widescreen television is 1.77:1 and this is often expressed as 16:9. Video Distributors can make DVD's in 4:3 and 16:9 aspect ratios from the appropriate video source.
4:3 -- Display devices such as televisions typically have their aspect ratio expressed in a way that does not reference the height as 1 unit. Hence a standard TV is 4:3 or 4 units wide by 3 units high which equals 1.33:1.
16:9 -- Display devices such as televisions typically have their aspect ratio expressed in a way that does not reference the height as 1 unit. Hence a widescreen TV is 16:9 or 16 units wide by 9 units high which equals 1.77:1. The image on VHS tapes (and television) has traditionally been stored as a 4:3 shape even when in the widescreen format commonly found on VHS Widescreen Editions known as Letterbox. This has been achieved by adding black bands to the top and bottom of the picture to restore the 4:3 proportions. Many movies are originally recorded in widescreen to give cinema audiences an enhanced viewing experience. The advent of DVD brings this concept to Home Cinema. When capturing widescreen video for a DVD an electronic flag is set which tells the player that the image is 16:9 rather than the traditional 4:3. When viewing a widescreen DVD on a TV one of two things can occur depending on the hardware configuration. If the TV is 4:3 then the DVD player is configured for this and it converts the playback video into Letterbox by shrinking it to fit in the screen and placing black bands on the top and bottom of the image. If the TV is 16:9 then the DVD player is configured for this and the playback video is played back without the black bands. For DVD's wider than 16:9 a lesser amount of black band is added to restore the 16:9 proportions. If the DVD player is configured wrong for the TV then the picture will be very squashed either vertically or horizontally.
Audio
MPEG audio -- A stereo or multi-channel, digital audio format created by Moving Picture Experts Group. One of the three required formats for PAL DVD-Video players. See also Dolby Digital, PCM.
PCM -- Acronym for Pulse Code Modulation. An uncompressed (lossless) digital audio format. The format used for CD-Audio and one of the required audio formats for DVD-Video Players. See also Dolby Digital, MPEG audio.
Linear PCM (LPCM) -- See PCM.
Dolby Digital -- Also called AC-3. Multichannel surround-sound audio encoding, used for cinemas and the home. Supports one to five full-range channels, plus a Low-Frequency Effects channel for carrying low bass sounds. The five channels are Front Left, Front Centre, Front Right, Left Surround, and Right Surround. Full surround-sound Dolby Digital is referred to as "5.1," for these five channels plus ".1" for the low-frequency channel. DVD-Video discs for NTSC are required to provide at least one Dolby Digital or PCM audio track. PAL/SECAM discs are required to provide at least one Dolby Digital, PCM, or MPEG-2 audio track. Discs may also have a separate stereo track, or DVD players can downmix a surround-sound signal to stereo. See also MPEG audio and PCM.
Authoring Terminology
DVD Authoring -- The process of creating a DVD-Video disc. This could be as simple as importing the content but may also involve configuring the content into Titles, Tracks, and Chapters, designing navigation Menus, linking the content to the menus, and rendering the project to write to DVD, hard disk, or DLT tape.
First Play -- Identifies the first item to be played when a DVD is first inserted in a player. Typically, an introductory sequence such as a copyright notice. This item can not be skipped. If there is no First Play item it will proceed to the Title menu.
Title -- This is a single continuous video item on a DVD-Video. It can contain marker points known as Chapters. If it is desired to return to the menu after an item it must be a Title. (Separate entity)
Chapter -- This is a marker point within a Video Title. It can be accessed via the remote control or a menu button but will play to the end of the Video Title when selected. Sometimes known as a scene in a DVD movie which can be broken up into sections much like the chapters of a book.
Track -- An alternate component of content such as another language or type of audio which can be selected with the remote.
I-Frame -- In an MPEG2 video file the full picture data is only recorded every 15 frames or so. The other frames contain difference information. For this reason edits and chapters need to be on I-Frames. This also means that the accuracy of these points is approximately 0.5 seconds so this needs to be allowed for when setting these points.
Slide Show -- A DVD made from a set of static pictures which each display for a predetermined time enabling presentations to play like a video. Each picture behaves like a chapter in a video and Menus can be included.
Regional Coding -- A code inserted on a DVD to restrict playback to certain groups of countries. The most common are Region 1 for USA and Canada, Region 2 for Japan and most of Europe, and Region 4 for New Zealand and Australia. The region code has no relationship to the television standard but a Region 1 PAL disc would be a nonsense as virtually no DVD players would be able to play it. Do not use this feature unless absolutely necessary.
Copy Protection -- The DVD specification provides for copy protection by one of two main mechanisms called CSS (Content Scrambling System) and Macrovision. These seek to prevent copying either by recording the DVD to tape or on a PC. DVD's containing copy protection can only be manufactured by replication and must be supplied on a DLT.
DLT -- Acronym for Digital Linear Tape. A half-inch magnetic tape format used for transferring pre-mastered DVD productions to a replication facility for manufacturing especially where DVD-9 or copy protection is required.
Menu Terminology
Menu -- The main mechanism for navigating DVD productions. Typically consists of a background (still image or motion video), title text, buttons or thumbnails to link to different elements of the DVD (menus, titles, chapters or tracks), and background audio. The viewer navigates the menu with the Remote Control to step through the buttons; and then presses Select to activate the currently-highlighted button. Some functions can be programmed to happen automatically after a predetermined time if no selection is made. See also button, motion menu.
Menu background -- This is a picture or even a complete menu graphic on which the menu is built. If a complete menu image is supplied invisible buttons are overlaid to make it functional. This image should preferably be supplied in .bmp format with dimensions of 768x576 pixels. The safe area for text and buttons is 614x460 which is 77 pixels from either side and 58 pixels from top or bottom.
Button -- A selectable option on a DVD menu. Buttons can be graphics, text, thumbnail images, or motion video; with graphical highlighting to indicate the current selection state.
Thumbnail -- A menu button in the form of a small picture representing the scene to be played. The picture used can come from anywhere in that scene.
Motion Menu -- A DVD menu that incorporates motion video as the background image and/or in the thumbnail buttons to link to video tracks. The video is typically a short clip that repeats until a menu selection is made.
Title menu --The menu in a DVD Video designated as the Top or main menu for the disc. The Title menu is typically displayed when the disc first starts playing (sometimes after the First Play item), and contains navigational links to the contents of the entire disc. The viewer can access this menu at any time by pressing the Title key on the DVD remote control. See also First Play.
Setup menu -- For set-top DVD players, a menu built in to the player hardware to access global system parameters such as the preferred language and parental controls. For commercial movies on DVD, a menu that typically provides access to alternate audio formats such as Dolby Digital 5.1 surround sound, alternate audio tracks with different languages, and subtitle text.
Scene Index menu -- A DVD menu screen or linked set of screens that contains buttons or thumbnails to link to each video title or chapter within a video title. Commercial movies on DVD typically contain a Scene Index to jump directly to a specific scene and then play from that point to the end. . Also called Chapter Index menu.
Repeating Play -- A menu function which causes the DVD to keep playing repeatedly until ejected. The does not require the user to set their DVD player to repeat.
Remote Functions
Title key -- A dedicated key on DVD remote controls that returns playback to the Top or main menu for the disc. The action of this key is defined by the DVD author. See also Menu key, Return key, Video Title Set.
Menu key -- A dedicated key on DVD remote controls that typically returns playback to the main menu for the current section of the disc (that is, the current Video Title Set). The action of this key is defined by the DVD author. See also Return key, Title key.
Return key -- A dedicated key on DVD Remote Controls that is typically used to return back to the most recent menu from which the current menu was accessed. The action of this key is defined by the DVD author. See also Menu key, Title key.
Skip or Prev/Next keys -- These keys enable the viewer to skip forwards or backwards to chapter markers in the program.
Production Terminology
Duplication -- This is the process of copying CD's or DVD's by burning the image on CD-R's or DVD-R's. It is normally only used for quantities less than 500 unless time is very short.
Replication -- This is the process of copying CD's or DVD's by the process of stamping or pressing the discs from a master called a stamper. It is only used for quantities in excess of 500 due to the high set up costs for this process.
Printing and Packing
Printing -- Printing can be applied as a disc label, jewel case insert or the slick for a DVD (Amaray) case. Print files should be supplied at a resolution of 300dpi and sized appropriately to the end use.
Slick -- This is the printed paper cover which is inserted under the clear outer film of a DVD case. A slick for a standard DVD case should be 272mm x 182mm.
Jewel Case Insert -- A jewel case insert should be sized at 120mm square. This can be a booklet. Standard size Jewel cases can also take a 150 x 118mm inlay which has 6mm folded up at each end to form spine labels.
CD or DVD Label -- The disc can be printed with text or an image of 118mm maximum diameter. For replicated discs a minimum allowance of 20mm for the centre hole needs to be made. For duplicated discs as much as 43mm allowance may need to be made so no important information should be in this area.
CD and DVD Cases -- Listed below are some of the most commonly used CD and DVD cases and sleeves which Video Distributors can supply -
DVD (Amaray) Case -- The most common type of plastic storage case for DVDs especially movies and is capable of holding a booklet. Double disc versions are available but slick dimensions and booklet capability may vary. Please enquire.
Jewel Case -- A hard clear plastic case used mostly for Audio CD's also available in a slimline version or two disc version. Can take a 120mm square booklet. The standard case can take a rear insert as well.
Clam Shell -- A cheaper plastic DVD case often round which takes up little space and is suitable for posting and shipping where some physical protection is required for the disc.
Plastic Sleeve -- A transparent disc sized plastic envelope.
Paper Sleeve -- A paper disc sized envelope with a circular clear window on the front.
