What is DVD?
DVD, which stands for “digital versatile disc”, is the next generation of optical disc storage technology. It's essentially a bigger, faster CD that can hold cinema-like video, better-than-CD audio, and computer data. DVD aims to encompass home entertainment, computers, and business information with a single digital format, eventually replacing audio CD, videotape, laserdisc, CD-ROM, and video game cartridges. DVD has widespread support from all major electronics companies, all major computer hardware companies, and all major movie and music studios. With this unprecedented support, DVD has become the most successful consumer electronics product of all time in less than three years of its introduction.

What are the features of DVD-Video?
Over 2 hours of high-quality digital video (a double-sided, dual-layer disc can hold 8 hours of high-quality video, or 30 hours of VHS quality video).
Support for widescreen movies on standard or widescreen TVs (4:3 and 16:9 aspect ratios).
Up to 8 tracks of digital audio (for multiple languages, DVS, etc.), each with as many as 8 channels.
Up to 32 subtitle/karaoke tracks.
Automatic "seamless" branching of video (for multiple story lines or ratings on one disc).
Up to 9 camera angles (different viewpoints can be selected during playback).
Menus and simple interactive features (for games, quizzes, etc.).
Multilingual identifying text for title name, album name, song name, cast, crew, etc.
Instant rewind and fast forward
Instant search to title, chapter, music track, and timecode.
Durable (no wear from playing, only from physical damage).
Not susceptible to magnetic fields. Resistant to heat.
Compact size (easy to handle, store, and ship; players can be portable; replication is cheaper than tapes or laserdiscs).

Most players support a standard set of features:

Language choice (for automatic selection of video scenes, audio tracks, subtitle tracks, and menus).
Special effects playback: freeze, step, slow, fast, and scan (no reverse play or reverse step).
Parental lock (for denying playback of discs or scenes with objectionable material).
Programmability (playback of selected sections in a desired sequence).
Random play and repeat play.
Digital audio output (PCM stereo and Dolby Digital).
Compatibility with audio CDs.

What makes DVD better than VHS Video Tapes?
A DVD has much greater data than a VHS Tape and although a DVD disc looks identical to a music CD, in fact it is capable of storing up to 25 times more data. This means that it has ample room for many of the exciting additional features that are to be found on DVD. It also means that a DVD offers superior sound and vision quality.

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QUESTIONS ABOUT REGIONS

What is Regional Encoding?
There are 6 Regions assigned to the release of DVDs worldwide. Why?

Motion picture studios want to control the home release of movies in different countries because theater releases aren't simultaneous (a movie may come out on video in the U.S. when it's just hitting screens in Europe). Also, studios sell distribution rights to different foreign distributors and would like to guarantee an exclusive market. Therefore they demanded that the DVD standard include codes that can be used to prevent playback of certain discs in certain geographical regions. Each player is given a code for the region in which it's sold. The player will refuse to play discs that are not coded for its region. This means that discs bought in one country may not play on players bought in another country.

The regions are:

Region 0: No Restriction – Worldwide availability, playing on all machines.
Region 1: Canada, USA, US Territories.
Region 2: UK, Europe, Middle East (including Egypt).
Region 3: Southeast Asia, East Asia (including Hong Kong).
Region 4: Central America, South America, Mexico, Australia, New Zealand, Pacific Islands, Caribbean.
Region 5: Russian Federation, Africa (not Egypt), North Korea, Mongolia.
Region 6: China.

Therefore originally, a European consumer who purchased hardware in Europe, would only be able to obtain playback on Region 2 discs. This was so for the first few players available on the market when DVD first became available. Then the fast pace of technological change brought forward multi-region players, allowing consumers to playback discs purchased from other regions.

Please contact your DVD hardware retailer or manufacturer for further information if you do not know whether you have a multi-region player.

What is a multi-region DVD Player?

DVD disks in the UK are marked or coded as 'region 2', and those in the US are 'region 1'.  Most players you buy here are set to play region 2 disks only, and won't play region 1 disks.

The US television standard is NTSC, whereas the UK standard is the superior PAL, and at present not all UK televisions are able to display an NTSC signal even if you have a multi region DVD player. It is recommended that you check the compatibility of your television in this way. The use of regions in DVDs is often a marketing restriction, to stop you viewing films before the distributors want to release them here. 

As region 1 discs give extra choice, CD WOW! recommends that you buy a multi-region player that is able to play DVDs from any region.

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Aspect Ratio
The numbers for the aspect represent the ratio for the width of a fullscreen or widescreen format in relation to its height. There is more than one way to express an aspect ratio.

The standard television picture is 4 units wide by 3 units high or ratio 4:3. Although it seems simpler to use the format 4:3 for fullscreen instead of 1.33:1 (when you divide 4 by 3 you get 1.33333etc.), it is easier to understand widescreen formats using the decimal measuring system. It is obvious that a 2.35:1 screen is wider than a 1.78:1 screen, rather than saying a 47:20 screen is wider than a 16:9 screen, even though the ratios are the same.

Fullscreen
Fullscreen is the Standard Aspect Ratio for television (4:3 or 1.33:1), which means that the width of the screen is precisely one and a third more than the height. Fullscreen films fill the entire screen area of normal televisions and if they are played on widescreen televisions, you will see black bars on each side (left and right) of the screen.

Widescreen
A widescreen television has an Aspect Ratio of 16:9 (or 1.78:1). Widescreen is the original size of the theatrical presentation, filmed in various aspect ratios. This format was first introduced around 1950 so that theatres could compete with television.

In widescreen “Letterboxed” versions it is normal to see a black strip at the top and bottom of the screen, although its thickness depends on the aspect ratio. The only exception is that if the picture is mastered in the ratio 1.78:1 (or 1.77:1 as some producers incorrectly call 16:9) then the widescreen will be filled.

Two of the most common aspect ratios are 1.85:1 and 2.35:1 which measure the width of the picture in relation to its height. Therefore, the wider the screen (or higher the decimal number), the thicker the black bars will be.

Anamorphic Widescreen
The “Anamorphic Widescreen” technique allows for a superior picture quality, without altering a film’s aspect ratio. Knowledgeable DVD buyers often demand it. Consumers new to DVD and even old enthusiasts are still confused by the technology.

Unfortunately the studios and producers have not helped as the back of DVD covers include such catchphrases as “enhanced for 16x9 televisions”, “widescreen 16x9”and “16x9 anamorphic”, due to the fact that the artwork for a DVD is often lifted and copied word for word from the original theatrical release.

The correct terminology is “anamorphic widescreen”. However, aCD WOW! our policy is to not change any of the descriptive information passed on to us from the studios, our suppliers and even from the back cover artwork, in order not to create yet more confusion.

In the transfer from film to video, the image is stretched vertically, therefore giving about 33% more vertical scan lines (and thus a higher vertical resolution). When viewed on a widescreen television or on a computer screen, the image is again stretched 33% ­ this time horizontally instead of vertically ­ to fit the screen. But what if you want to view it on a standard television? You wouldn't want to see the vertically stretched image; everything would look tall and thin.

DVD players are designed to squeeze the image back down to normal for standard television sets. They use weighted averages to combine lines, scaling the image back down by 33%. You can set up your DVD player to tell it which type of TV set you have in order to select the most appropriate picture mode.

You may be wondering why this new and improved technique is not applied to all discs. Some of the studios have not embraced anamorphic widescreen because of the fact that there are a limited number of 16:9 and 4:3 monitors capable of performing the required vertical squeeze. As a result, many consumers are forced to use the player’s hardware to convert the anamorphic widescreen images to 4:3 for a fullscreen image. Please refer to your instruction manuals, hardware retailer or manufacturers for further information.

Dolby and Dolby Digital
“Dolby” is a proprietary audio coding technique used in “anauelog” formats, developed by Dolby Laboratories for storing and transmitting single or multiple channels of audio. The term “Dolby” often causes confusion among consumers purchasing DVD discs, as the studios, producers, suppliers, distributors, back cover artwork and retailers describe older DVD discs (or new releases of classic movies) as having “Dolby” audio. Almost all DVDs contain audio in Dolby Digital format, NOT ANALOGUE; every DVD player contains a Dolby Digital decoder.

Dolby Laboratories have advised us that unfortunately the movie authorising houses are not displaying the correct technical terms related to digital mixing on the back cover of disks. Dolby Laboratories produce a document called “Dolby Trademark Use On DVD” which the authorising houses are supposed to adhere to with regard to logo layout, but it too can be somewhat confusing as to what audio formats actually mean.

At CD WOW! our policy is not to alter the information given from the studios, producers, suppliers, distributors and the back cover artwork of any DVD discs, so as to not confuse consumers any more.

“Dolby” formats that you may find listed in the "Sound" section of a DVD's technical details are listed below and have been checked for their accuracy with our contacts at Dolby Laboratories.

All the following formats are Digital even where only the term Dolby (which indicates an analog recording in other media) has been used to describe the sound. Any formats not listed below can be considered to be non-standard or just plain incorrectly labelled ­ as advised to CD WOW! by our sources. On a brighter note it seems that newer discs are now showing more accurate labelling, especially because of the fact that films are now nearly all produced in the 5.1 format. Hopefully the confusion of the past is behind both DVD retailer and consumer.

Dolby Mono
(1.0) Contains only one channel of recorded audio.

Dolby Stereo
(2.0) Contains two channels of recorded audio.

Dolby Surround
(4.0 or 2.0) Dolby Surround is the consumer version of the original analogue Dolby multichannel film sound format. When a Dolby Surround soundtrack is produced, four channels of audio information - left, centre, right, and surround - are encoded onto two audio channels. These two tracks are then carried on stereo program sources, where they can be processed by a Dolby Surround Pro Logic decoder (now standard in most home theatre systems and components) to recreate the original four channels and the surround sound experience.

Surround (Pro Logic)
Dolby Pro Logic is a decoding technology and the successor to Dolby Surround, containing an added dialogue channel.

In the beginning, Dolby Surround decoders simply fed the entire program in normal stereo to front left and right speakers, and the surround signal derived by a simple passive matrix decoder to the surround speakers.

Dolby Surround Pro Logic decoding was then developed which, like professional Dolby film processors, actively derives a separate centre channel to keep dialogue and other central sounds firmly localized on the screen for all viewers, even those off to the sides. Dolby Pro Logic also supplies higher separation among all four channels for more accurate sound positioning. As a result of its higher performance and steadily decreasing cost, Dolby Pro Logic today is standard in virtually all home theatre systems and components.

Dolby Digital Mono
(1.0) Contains only one channel of recorded digital audio.
(2.0) This format will seem a little confusing at first. Two Channel Mono plays one language from the left speaker, whilst it can also play another language from the right. Allowing discs with mono recordings to have multiple language tracks.

Dolby Digital Stereo
(2.0) Contains two channels of recorded digital audio played into a left and right speaker.
Dolby Digital (Surround)
(3.0) describes the configuration of one left and right front channel, as well as one centre channel encoded discretely.
(5.0) describes the standard discrete surround-sound configuration of three full-range front channels and two-full range surround channels.
(5.1) describes the standard discrete surround-sound configuration of three full-range front channels, two-full range surround channels, and a bass-only low-frequency effects channel.

What is Dolby Digital 5.1
Dolby Digital 5.1 is an audio system that provides six separate channels of sound, fed through to five satellite speakers and a subwoofer. The idea is that you have three front speakers -- positioned left, right and centre -- to provide accurate positioning for dialogue. Two rear speakers handle ambient sounds, and the subwoofer kicks out explosions and rumbling subsonics. Dolby Digital (5.1) delivers a soundtrack in a third of the “space” of a DTS bitstream, by compressing the available data by a ratio of 12-to-1. This offers the studio the option to include three different languages, instead of a single "master quality" DTS soundtrack. It allows you to reproduce the film's soundtrack in your own home, exactly as it was heard in the cinema.

What is Dolby Digital 6.1
Dolby Digital 6.1 is the latest Dolby technology that provides full-frequency surround sound in all channels -- 6 surround channels and an optional subwoofer source. For more information about this new technology visit the Dolby website.


DTS
DTS (Digital Theatre Systems) is an encode/decode process that delivers 5.1 channels of “master quality” audio on D.VD Each DTS encoded disc represents a sonic “clone” of the original film soundtrack.

DTS in comparision to Dolby Digital (5.1) offers:

Subtle Nuances - Every individual sound effect is crystal clear, adding to the sonic realism of the soundtrack.
Dynamic Range - The loudest "bangs" have more depth, and the quietest passages are "noise-free".
Channel Separation - All 5.1 channels operate at full potential without sonic "bleeding" or "collapsing"

Although DTS offers more realistic audio, the soundtrack does take up more space on a disc compared to a Dolby Digital Soundtrack. However, there is still ample space available on the disk to add such features as trailers, commentaries and documentaries.

Unfortunately some DTS-encoded DVDs may be released with fewer (or different) extras than the non-DTS versions. This is simply the decision of the producer of the disc, and not usually the result of space limitations. All DTS DVDs play in 2-channel (stereo) on all DVD players within their respective DVD regions.

To experience 5.1 channels of DTS Digital Surround, you need a DVD player with the DTS "Digital Out" logo, plus a surround processor (pre-amp or receiver) with a built-in DTS decoding circuit.

THX
LucasFilm ® began research on the Home THX audio system in 1985 and by 1990 the Home THX Program was introduced.

Home THX Audio System is the ultimate in sound for multi-channel home entertainment systems. The system incorporates a series of patented electronic and loudspeaker developments designed to reproduce all multi-channel sources accurately in the home.

Home THX was created because conventional audio components could not accurately reproduce film soundtracks in the home environment as they were originally created by filmmakers. Thus sound engineers addressed the following points:

A need to correct the audible tonal and spatial errors caused by the playback of soundtracks designed in and for large theatres in the smaller environment of a home.
A need to more accurately reproduce the complex and competing sound fields present in multi-channel sound playback
Dolby Laboratories™ and the THX division of LucasFilm® developed THX Surround EX, where an additional surround back channel is matrix encoded into the surround left and surround right channels of discrete Dolby Digital (5.1) motion picture soundtracks.

This audio format is also available on DTS discs. The correct terminology for EX-encoded soundtracks delivered by DTS 5.1 is DTS Digital Surround Dolby Digital Surround EX. At CD WOW! we have abbreviated the name to DTS/Dolby Digital Surround EX for easier readability.

THX Optimode
A unique new DVD software feature was unveiled in June, 2000 from LucasFilm THX® which allows the performance of a home theatre system to be optimized for individual DVD releases. THX Optimode™ (patent pending) is a new innovation from the THX Digital Mastering Program that consists of a series of tests that make it easy for consumers to fine-tune the audio and video performance of their home components. Any future titles available with this process will be listed under “Special Features” once we have received information from our suppliers or the disc itself on release.

As part of the Digital Mastering Program Certification process, THX engineers place the Optimode test signals on the same digital videotape as the movie. Both the movie and the test signals then follow the same path during the DVD production process. As a consequence, adjustments made using these signals relate directly back to the reference levels set during the mastering of that specific title. THX®Optimode™ featured on DVD contains a range of test signals and clear instructions for the consumer to optimise both video and audio presentations. LucasFilm® states “to adjust video performance, there are tests for contrast, brightness, color, hue, monitor performance and aspect ratio settings. To adjust audio performance, THX Optimode provides tests for speaker level, speaker phase and Low Frequency Effects (LFE) channel crossover. The phase test employs both an audible signal and an on-screen graphic to assist in checking the wiring. In some cases, there are performance parameters that are best tested and adjusted by the consumer's custom installer or a certified Home THX dealer.”

More detailed information about the tests, what they measure and how they are best performed is available at the THX website.

Linear Pulse Code Modulation (Linear PCM)
All DVD players have to be able to play Linear Pulse Code Modulated (Linear PCM) audio. Linear PCM is an ultra high quality digital audio.

Although DVD players have to play Linear PCM discs, there is no requirement for the incorporation of Linear PCM audio. A publisher of a disc may decide that Dolby Digital audio is sufficient for the disc. Although the publisher is risking losing a sale of a disk if a buyer’s player does not support this format.

DVD discs may have one to eight tracks of Linear PCM, but all audio channels combined can not exceed a bit rate of 6.144 Mega bits per second (Mbps). To maintain audio quality this limit will generally limit the audio on DVD discs to no more than five separate channels. All DVD players are required to support the different combinations of Linear PCM but some may not be able to sample at the high 96 kHz rate.

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