AC-3   

Originally conceived in 1987 as a multi-channel audio-encoding scheme for movie theaters. In the home, Dolby Digital Surround is based on the AC-3 model. This system only encodes data that can be heard under normal circumstances, with any extraneous information being discarded.

Anamorphic   Back to top

DVDs that are specifically enhanced for widescreen televisions. Anamorphic DVDs contain 33% more resolution than conventional widescreen DVDs. They are usually labeled "Anamorphic Widesceen" or "Enhanced for Widescreen TV". A non-anamorphic DVD will letterbox the movie using only 345 lines of resolution for the image; an additional 135 lines are wasted on black bars (top and bottom). An anamorphic DVD uses 462 lines of resolution; only eighteen lines are wasted on black bars.

You can still view an anamorphic DVD on a conventional 4:3 TV but every fourth line of resolution will be removed from the image.

Aspect Ratio   Back to top

The shape of the screen image represented as a proportion of width to height. 16:9 is the average widescreen ratio, while 4:3 represents the rather square TV image.

If your DVD doesn't have these icons, then look for a note that starts with "Dolby Digital". Text below this notes the particular type of audio on your DVD.

Dolby Digital Surround   Back to top

A DVD can contain 5.1 channels of Dolby Digital sound--six audio channels: left, center, right, left rear, right rear, plus a subwoofer channel that handles only lower frequencies (the ".1" of 5.1 channel audio). Dolby Digital sound streams on a DVD can range from one channel mono to six channel 5.1

DTS   Back to top

Digital Theater Surround - DTS was introduced to the world in 1993 with the release of Jurassic Park. It is currently the industry standard for DVD home theater audio. DTS uses far less compression than AC-3 resulting in audio that, at least in theory, should sound better. A DTS DVD must contain a Dolby Digital soundtrack or a PCM soundtrack in addition to the DTS soundtrack in order to maintain compatibility.

DVD+R   Back to top

DVD-R against DVD+R ? A glimpse to a chaos. Click here.

Dual Layer   Back to top

The DVD format allows a single side of a DVD to consist of a sandwich of two layers, each of which can be individually read by the player's laser. These layers can consist of segments of the film, or the film plus special features like director's comments or deleated scenes. This dual layer technology allows more information to be stored on a single disc.

Easter Eggs   Back to top

Many DVDs contain "hidden features" stored on the disc, which can usually be accessed by some hidden icon on a menu screen. this practice is becoming more and more common, and is even becoming a promotional device for many distributors.

Interactive Menus   Back to top

Also known as navigation menus. An interactive menu is a series of screens or pages that allow the viewer to navigate and select different features on a DVD. Uses include: selecting different scenes in a movie, changing language or subtitle options, accessing special features, etc. 95% of all DVDs currently contain navigation menus and as the format matures, menus are becoming more and more elaborate, with music, graphics and animation.

Letterbox   Back to top

A rectangular image banded on the top and bottom by black bars. On a common television with its 4:3 aspect ratio, it is necessary to include these bars in order to accommodate a widescreen image. The letterboxed image contains all of the information from the theatrical release.

Multiple Audio Tracks   Back to top

A DVD disc can contain up to nine separate and continuous audio tracks. Viewers can select a particular track through the disc's menus or the remote control. The value of such tracks is that they can be accessed instantly and provide additional synched audio material along with the main soundtrack. Common uses: foreign languages, alternate soundtracks, isolated musical scores or audio commenatries by the director, cast and crew or others associated with the material.

Multiple Video Tracks   Back to top

One of the most interesting DVD capabilities is the ability to show different camera angles or different versions of a scene. When it comes to the technical side of things, multiple angles are merely alternate takes, alternate credits, additional storyboards or graphical content. These multiple video streams can be accessed instantly via a players "angle" function. DVD discs can contain up to 8 spearate video streams.

Pan & Scan   Back to top

The smaller TV window, with its roughly square display, is panned and zoomed around the wider movie picture, chopping off the sides. Although most movies are shot in what is called a "soft matte" (the full TV-sized film frame is used, with the top and bottom masked in the theater). The image in a "pan & scan" transfer may differ greatly from that intended by the director.

PCM   Back to top

An uncompressed 2 channel stereo or mono soundtrack. Many music-oriented DVDs contain PCM tracks. Due to the uncompressed nature of the audio, PCM tracks are a favorite among audiophiles.

RSDL   Back to top

Reverse Spiral Dual Layer allows longer movies to fit onto one side of a DVD, allowing continuous play for longer programs and no need to "disc flip". Usually, about 133 minutes of video will fit on a single layer. However, an RSDL disc can hold about four hours or more of uninterrupted video and audio. A dual-layer disc is easy to spot because of it's gold color, as opposed to the silver appearance of the single-layered variety.

Scene Access   Back to top

With your DVD player you may pick from a list of chapters to get to a certain scene, usually accessed via the menu or by pressing the corresponding chapter number on the remote.

Stretching Effect   Back to top

A problem noticed when backplaying PAL/R2 Anamorphic discs at 16:9 aspect ratio (wide screen) on 4:3 aspect ratio NTSC TV (the regular North American TV).The objects (especially people) will look in these pictures skinny and abnormally stretched up.
This problem is commonly found in DVD players incapable of XY scanning during the PAL/NTSC conversion process (not to be confused with "Progressive Scan").

Stretch Effect

Proper Conversion

THX   Back to top

THX is not another sound format, but a set of quality control standards set by Lucasfilm. The full effect of a THX mastered disc is delivered using equipment that has been marked with the THX seal of approval. Even without THX equipment, a THX DVD is generally thought to be of better quality both in regards to sound and video.

VCR Friendly   Back to top

Some old TV sets are not provided with a VIDEO input jack. The VCR friendly feature enables the connection of the DVD player's 'video output' through the VCR video input jacks and analog output (NTSC or PAL) jacks to the TV without any distortion of the analog video signal. It is illegal to use this feature to record the content of a DVD disc on to a VHS tape.
The VCR Friendly feature will not work with digital VCRs (or VTRs) because of the Serial Copy Management System (SCMS). Read Mitsui Advanced Media explanation on digital to digital blocking here.

Video Compression   Back to top

Audio and Video information are stored on your DVD in a compressed format. Without compression, a single sided, single layer DVD could only store 4 minutes of full motion video.

Widescreen   Back to top

A standard television is almost square. A movie shown in a theater is not shown square, but as a wider rectangle of a varied aspect ratio. To allow for a film to be shown on video in its original widescreen aspect ratio, black bars are placed at the top and bottom of the screen, thereby preserving the original width of the image (called letterboxing). DVD also allows for anamorphic widescreen transfers.

Zone Codes   Back to top

Since movies are released in different countries at different times and studios don't want DVDs on sale in a place where the movie has yet to enter theaters, they sometimes program codes to prevent certain discs from being played in certain places. In other words: if you buy DVDs on a whirlwind trip to Hong Kong or Italy they probably won't play in your zone 1 (US & Canada) DVD player.

DVD Regions

• USA, Canada, U.S. Territories
• Japan, Europe, South Africa, Middle East (including Egypt)
• Southeast Asia, East Asia (including Hong Kong)
• Australia, New Zealand, Pacific Islands, Central America, Mexico, South America, Caribbean
• Former Soviet Union, Indian Subcontinent, Africa (also North Korea, Mongolia)
• China

Players configured (either manually or automatically) to playback all region/zone codes are known as international or worldwide versions.   See regions map here