This is the first in a three-part series on the basics of Digital Video Discs.
DVD has been commercially available for nearly a decade and has revolutionized the home theater market. Yet purchasing DVDs can be confusing and complicated. The back of a DVD case often contains terms like aspect ratio, Dolby Digital and regional DVD. For many, it is difficult to understand what is worth purchasing and what is not. Hopefully this guide will demystify many of the more confusing features of the video market.
What is DVD?DVD stands for digital video disc. It is an optical laser audio and video technology that is most often used for movies, but sometimes music and other information as well.
RegionsTo protect from piracy, companies and studios encode into regions, or specific targeted markets. The United States and Canada are Region 1, while Japan, Europe, South Africa and Middle East are Region 2, etc. This is displayed in a small number on the back of the DVD. In order to play a DVD from a different region, you will need a region-free DVD player. Additionally, some imported DVDs are region-free.
Aspect RatiosIn many cases a consumer is given the choice between widescreen and full screen formats. In nearly every case, the widescreen edition is preferable because it preserves the original aspect ratio of the film. An aspect ratio is the proportion of width to height (for example, many movie theater screens are 2.35:1, which means they are 2.35 times longer than they are tall). However, a standard television has a ratio of 1.33:1 while a widescreen film is usually either 1.85:1 or 2:35:1. This accounts for the black bars above and below the image, which are normal and a necessary side effect of imposing a more rectangular image onto a more squared screen. This process is called letterboxing. The widescreen ratio is 16 x 9 while a full screen ratio is 4 x 3.Full screen often uses a technique called pan/scan to fit an image into a standard television ratio, which actually cuts off the sides of a film. Up to 40 percent of visual information can be lost in full screen. A common defense of full screen is that no important or pertinent visual information is lost. This is absolutely untrue.There are exceptions to the widescreen preference. Foremost is in older or classic films - the widescreen ratio was not invented until the 1950's, so most films prior to that time will be in a full screen format. This is the correct way to watch such movies since it is how they were originally filmed. If one is ever watching a widescreen version of "Casablanca" or "Gone with the Wind," for example, then you are watching an incorrectly framed and cropped version of the film.Other cases in which the widescreen/full screen preference becomes nebulous are in the case of a process called Super 35. In such cases, the movie is filmed in a 1.33:1 ratio with the intent of later cropping the film into a theatrically-presented ratio. This can often cause confusion as to which is preferable. In the case of director Stanley Kubrick, for example, he has stated the full screen versions are definitive; thus, the 1.33:1 framing of films like "The Shining" and "Full Metal Jacket" are the official DVD editions. This creates disparity between what was originally theatrically presented and what the director (the ostensible auteur of the film) prefers. A similar case would be the TV series "Buffy the Vampire Slayer," which is presented in widescreen in Region 2 and full screen in Region 1. Series creator Joss Whedon has gone on record claiming to prefer the full screen version.
Anamorphic WidescreenOften, the back of a DVD will say something like "Enhanced for Widescreen TVs", "Anamorphic" or "16 x 9 Version". This means the image is letterboxed on a standard TV and enhanced for widescreen TVs. An anamorphic image is encoded with additional lines of resolution that "unfold" on a widescreen TV. Not only will the image look better on a widescreen television, but the size of the black bars will be reduced, and the image itself will appear larger.
Sound FormatsDolby has become the standard for home theater surround sound. On a standard television without speakers or a receiver, the sound will automatically be decoded into two-channel stereo.Digital 5.1 is the typical Dolby home theater sound format. To encode into this format, there must be five speakers (one center, two front surrounds and two rear surrounds) and a subwoofer, which channels low frequency emissions. If a setup does not have this, then a standard television can automatically downgrade the sound into two-channel stereo.Dolby Digital 5.1 EX is a newer Dolby sound format, which encodes into a sixth speaker placed directly between the two rear speakers.For those who own a 5.1 set-up, Dolby uses technology called Pro-Logic, which encodes two-channel stereo programs into all five channels.DTS (Digital Theater Systems) Digital Surround is a separate sound technology format. Generally reserved for audiophiles, it is often used on action films or films with active surrounds and always on Superbit DVDs. Since it is a mix from a different company, the DTS mix will often sound different than a Dolby mix, which sometimes results in separate releases (for instance, "Jaws" is available in either a 5.1 Digital version or DTS Digital version). DTS requires special decoding equipment on both receivers and DVDs, so films containing DTS track usually also contain a Dolby Stereo track as well. In some cases, DTS is a vast improvement over the Dolby track ("Saving Private Ryan") while in others the difference is virtually unnoticeable ("Apollo 13").
