DVD, which once stood for Digital Video Disc, now stands for Digital Versatile Disc.    DVD is the 'next generation' compact disc format.  It's essentially a bigger, faster CD that can hold Video as well as 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 perhaps even video game cartridges.   DVD has widespread support from all major electronics companies, all majors computer hardware companies, and around half or the major movie and music studios which is unprecedented and say much for its chances of success In essence a combination of smaller pits etched into the disc, improved laser reading, double layered (whereby the laser skips between the top and bottom layer) and double-sided discs has increased the storage capacities over a standard CD-ROM by over 400% Even with this massive increase in storage capacity, it would still only be capable of carrying around four minutes of audio and visual movie information if recorded using standard methods. To enable a movie to fit on a DVD disc, a form of compression is needed.  In DVD this compression is called MPEG-2.   MPEG-2 uses a lossy compression that removes redundant information (such as areas of the picture that don't change) and information that's not readily perceptible to the human eye.  The resulting video, especially when it is complex or changing quickly , may occasionally contain visual flaws depending on the processing quality and amount of compression.   (Note:  To watch movies on a PC will require MPEG-2 support as well as a DVD-ROM drive). The primary advantages of DVD are quality and extra features.  Basically you get a format to replace magnetic tape videos that offers picture and sound quality as good as broadcast quality material.   DVD will not degrade with age or after many uses like videotape will (which is an advantage for parent with children who watch Disney movies many times a week!)  There is also the same 'collectability' factor which is present with CD's and Video cassettes. DVD sound quality is superb to say the least.  Most DVD-Video discs contain Dolby Digital soundtracks.  Unlike Dolby Surround which has a mono surround channel split across the rear speakers, Dolby Digital 5.1 has two completely independent surround channels that offer true stereo separation across the rear speakers.   5.1 represents Front Left, Front Right, Rear Left, Rear Right and Centre (which equals 5 channels) and the extra (.1) represents a subwoofer which takes the low frequency (bass) sound. So who buys DVD?  The following groups have been identified as possible customers for the DVD formats. People who want exception picture quality. People who want exceptional sound quality from a movies People who buy and collect movies.     REGIONAL CODING!  Every DVD buyers worst nightmare comes true. 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 the screens in Europe).  Also, studios sell distribution rights to different foreign distributors and would like to guarantee an exclusive market.  Therefore they have required 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 ion which it's sold.  The player will refuse to play discs that are not allowed in that region.  This means that discs bought in one country may not play on player bought in another.  Regional codes are entirely optional for the maker of a disc.  Discs without codes will play on any player in any country.  It's not an encryption system, it's just one piece of information on the disc that the player checks.  Some studios originally announced that only their new releases will have regional codes, but so far almost all releases play in only region.  Region codes are a permanent part of the disc, they won't unlock after a period of time.   There are eight DVD regions (also known as "locales").  A disc may play in more than one region. Canada, U.S. and U.S. Territories Europe, Japan, South Africa and Middle East (including Egypt) East Asia and SouthEast Asia Australia, New Zealand, Pacific Islands, Central America and South America Former Soviet Union, India / Pakistan and Africa (also North Korea) China Reserved Special International Venues (aeroplanes, cruise ships etc.)   Click map to see enlarged version.   Many DVD players are manufactured with the capability to play all regions, and it is only before export to another country that the code is set for its intended destination. The act of 'chipping' DVD players is very common in the UK.  This usually voids the warranty.  Some discs, such as those from Buena Vista (Disney) / Touchstone (Disney) / Miramax / MGM / Universal and Polygram contain program code that checks for the correct region.  These "smart discs" won't play on code-free players that have their region set to 0, but they can be played on code-switchable players that allow the user to change the region from the handset.  They may also not work on "auto-switching" players that recognise and match the disc region.  Information about modifying players can be found on the internet.   CERTIFICATES and FILM CLASSIFICATION There are various different certificates issued for films from the various countries. The UK Certificates are: U (Universal) Suitable for All PG (Parental Guidance) Generally suitable for all. But parent's may be advised to watch with small children 12 Suitable only for persons of age 12 and above. 15 Suitable only for persons of age 15 and above. 18 Suitable only for persons of age 18 and above.   DVD CONNECTIONS The simplest way to connect a DVD player to your TV is via a SCART socket.  Most DVD players are usually supplied with a basic SCART-SCART lead but it well the money in upgrading to a high quality one.    Another option is to use an S-Video connection.   The S-Video connection has a four pin output and allows suitably equipped player to connect to input usually found on the Front or Rear of most modern TV's.   The S-Video format separates picture information into colour (chrominance) and brightness (luminance) with the end result being that picture details are sharper and colours richer.  No audio signals are present on S-Video connections so separate audio connections are required. Here are three possibilities, starting with the highest quality connection: Component video: This 3-jack connection will provide the ultimate in color accuracy, and more and more DVD players are including it. TV manufacturers have been slower to include a matching component video input, but it's now available on several models we sell.  S-video: Every DVD player we've seen has at least one S-video output, and most current mid- to higher-priced TVs have at least one S-video input. This connection yields superb picture quality — nearly as good as component video — but colors may not be quite as vivid and free from bleeding. Composite video (RCA jack): Virtually all DVD players and current mid- to upper-priced TVs include an RCA-type direct video input. A slight step down in overall sharpness and color accuracy from S-video, but still very good.     DVD AUDIO - The future? DVD-Audio is a new digital music format which devotes virtually all of a DVD disc's incredible data capacity to just audio, for the kind of sonic realism and detail that must be heard to be believed. DVD-Audio boasts a higher signal-to-noise ratio, wider frequency response, and wider dynamic range than CD. The new DVD audio discs will use their enormous data capacity to carry a vastly improved dynamic range and wider frequency response than is currently possible with normal CD's. The flexibility of the format allows DVD-Audio software to contain various channel configurations (such as 6-channel audio for home theater speaker systems, or 2 channels of ultra-high-resolution audio) and convenience features (such as lyrics, liner notes, and still images which display on your TV!). Look for higher-end DVD players that feature DVD-Audio compatibility (sometimes labeled "DVD-Universal" players). So the promise of breathtaking digital sound - even better than CD is set to become reality in the very near future.  Indeed, Technics launched their first consumer DVD-A player in mid-2000 but software is very thin on the ground at the moment so like most people, I shall be waiting a little longer until DVD-A is better supported by the recording companies.   The mighty PIONEER DVL-909. A combined DVD, LD and CD Player.   Audio and Video Convergence A DVD player can excel as a do-it-all movies and music box, but according to at least one senior industry figure, this idea of convergence has a big problem ñ the way we Brits live. In most homes, the hi-fi system is in one corner, the TV in another, and the two just don't communicate. It's for that reason, I reckon, that we'll carry on buying CD players as well as the new movie machines. That's a pretty sad state of affairs, but consider this: how many people do you know who have a perfectly good stereo cinema source (a Nicam VCR) yet don't connect to whatever hi-fi system they have? Maybe I've just touched a raw nerve? Well, it couldn't be easier: all it takes is a pair of standard phono interconnects from the audio outputs of the VCR to any line input on your hi-fi amp ñ or indeed the ëaux iní sockets on a mini system. Then you simply reposition your speakers either side of the TV (even if they're not magnetically shielded they should be fine about a half metre away from the screen), and you're in business. The video can both play movies in stereo and, in most cases, function as a stereo TV tuner for off-air use. The first objection is obvious: the VCR is under the TV, the hi-fi is somewhere else. So the connecting wire needs to be long, perhaps 5m pairs of interconnects, and they'll be expensive, right? Not so, provided you go along to your local Tandy or a similar outlet and pick up some wires. A 20ft (6m) set of Tandy Gold Patch interconnects will cost you just £17, and should be long enough to run from most TVs to the hi-fi. Alternatively, why not consider racking the video with the hi-fi kit: most are the right size to match, and it doesn't have to live under the TV, you know! Then you can use a long scart cable to hook it up to the TV. A reasonable 10m scart can be found from about £25. So your video only has a scart output, not phono jacks to connect audio to your amp? Under £10 will get you an adapter with the right sockets. Do all that and you're already halfway to building in the full surround experience, using an add-on Pro-Logic processor with your existing hi-fi system. Weíll come to choosing them at a later date, but one hint for now: any surround processor or amp you buy should have a set of six-channel inputs, making it compatible with Dolby Digital sources such as DVD players. For now, however, enjoy the experience of TV and video sound in hi-fi stereo.    I can recommend you to take a look at the following site: http://www.dvddemystified.com/dvdfaq.html   This FAQ is the most comprehensive that I have yet seen on any site anywhere on the net.   All your DVD questions will be answered here along with a great deal more information.

DVD Players Key Features Glossary AC-3 The previous name for Dolby® Digital, the digital audio industry standard for DVD. For more information, please see Dolby Digital, below. Anamorphic A type of widescreen display format optimized for playback on a TV with 16:9 aspect ratio. (See "aspect ratio" definition for more information.) Aspect ratio The ratio between the width and height of an image or display screen. The NTSC television standard is 4:3 (1.33:1). However, most movies are made for the wide screen of a theater, and are originally displayed at the wider ratios of 1.85:1 or 2:35:1. DVD's huge data storage capacity makes it possible to include multiple versions of a movie on a single disc. It's not unusual for a DVD disc to feature a Standard (4:3) version on one side and a Widescreen version on the other. For TVs with standard 4:3 screens, movies (whether on disc or tape) must be re-formatted to either "letterbox" or "pan-and-scan." If you usually rent or buy VHS movies, you're probably used to pan-and-scan. A DVD played in pan-and-scan mode provides an image with full height, but shows a central "window" that is only 75% of the original widescreen width. What this window shows is determined by the preferences of the person(s) performing the film-to-disc transfer. For letterbox mode the player uses a "letterbox filter" that adds horizontal black bars to the top and bottom of the picture. What you see is a short, rectangular image that maintains the movie's full original width. Letterbox has been popular for many years with laserdisc fans and other movie purists. DVD is the first consumer video format to make "anamorphic" widescreen mode available on a significant number of movie titles. If a movie's widescreen version is anamorphic, the packaging usually says, "Optimized for 16:9 viewing" or something similar. You should only play a movie in anamorphic mode if you're using a TV or projector with true 16:9 aspect ratio — on a standard TV, anamorphic will appear horizontally squeezed. A 16:9 aspect ratio works out to 1.78:1, which means you'll see more of the original image. Chrominance The color information portion of a video signal that describes an image's color shade and vividness. Component video signal A video signal in which the brightness (luminance) and color (chrominance)  portions of the signal are processed separately. Component video signals provide greatercolor accuracy than S-video or composite signals. Why is component video superior to S-video? Where S-video separates the luminance and chrominance portions of the signal, component video goes a step further and splits the chrominance portion into two components. The benefits — improved color accuracy and less color bleeding — are especially noticeable on larger-screen TVs. Composite video A video signal in which the brightness and color portions of the signal are combined. Examples of composite video include standard VHS, laserdisc, and regular broadcast TV. A DVD player's standard RCA-type video jack provides a composite video signal. Copy protection A system for preventing the unauthorized reproduction of copyrighted media like movies or music. The DVD format includes both digital and analog forms of copy protection. You will probably not be able to copy DVDs with your VCR. In fact, because the copy protection system is triggered by a circuit found in most VCRs, you should probably bypass the VCR altogether and connect your DVD player directly to your TV. Digital output All DVD players include at least one digital audio output for sending the Dolby Digital bitstream to a Dolby Digital decoder (either a stand-alone decoder or one built into an A/V receiver). Digital data transfer offers extremely wide bandwidth and immunity to RF interference. The two most common types of digital output are coaxial and optical. Both types require a special cable to connect to the digital input of your Dolby Digital receiver or decoder. Note: most DVD players do not include digital cables. Dolby® Digital A discrete multichannel digital audio standard offering enhanced sonic realism. Dolby Digital is normally associated with 5.1-channel surround sound. Though this channel configuration is common, it is only one of several possible variations — a "Dolby Digital" soundtrack can mean anything from 1 to 5.1 channels. If you're specifically looking for titles with a 5.1 soundtrack, you should carefully read each disc's packaging. Relatively few older movies with stereo or mono soundtracks will be remastered with 5.1-channel surround for DVD. Dolby Digital 5.1 soundtracks will in most cases provide the most satisfying sound quality for a home theater system. It is referred to as a 5.1-channel system because it offers five full-bandwidth channels (including true stereo surrounds), plus a "low frequency effects" subwoofer channel. Unless your DVD player has its own built-in Dolby Digital decoder, you'll need to connect your player to a receiver or processor that can take the digital bitstream from the disc and convert it into 6 channels of audio. Dolby Digital uses a data compression technique called "perceptual coding" to reduce the amount of audio data by a factor of about 10:1. Downmixed audio If you don't have a Dolby Digital system, you can still enjoy excellent Pro Logic or stereo sound. All DVD players have the ability to take a 5.1-channel Dolby Digital soundtrack and "downmix" it to two channels, which can then be sent to a stereo receiver, or to an A/V receiver with Dolby Pro Logic decoding. DTS (Digital Theater Systems) DTS is an established multichannel audio format in movie theaters, but a relative newcomer to home theater. Like Dolby Digital, DTS is a 5.1-channel format. The compression scheme used in DTS "throws away" significantly less audio data than Dolby Digital, so it should sound better, but so far A-B tests have been inconclusive. Although DTS-compatible DVD players and receivers are becoming more common, the number and availability of DVD titles with DTS soundtracks is still limited. Horizontal resolution The number of vertical lines that can be identified across the width of a TV screen, usually measured by displaying a test pattern. A bigger number is almost always better. DVD is capable of 500 lines of resolution. By comparison, laserdisc maxes out at 425 lines, Super VHS at around 400, and standard VHS at 240 lines. Luminance The brightness component of a color video signal. Determines the level of picture detail. MPEG2 The digital video signal compression standard used for DVD. This adaptive, variable bit-rate process is able to allocate more bits for complex scenes involving a lot of motion, while minimizing the bits in static scenes. The average data rate for DVD is 3.5 Mbps (million bits/second). Some DVD players can display an on-screen "bit rate meter" — a visual measure of data flow in the form of a bar graph. MPEG stands for Moving Picture Experts Group. Multi-language capability DVD is designed to make it easier for movies to be distributed in multiple languages. A single DVD disc can contain soundtracks in up to 8 different languages! In addition to multilingual dialogue, a DVD also has space for subtitles in up to 32 languages. Note: the number of soundtracks and subtitles will vary from disc to disc depending on the length of the movie and whether or not other special playback features are included. Parental lockout Some DVD movies will be available with variable ratings capability. According to the movie rating level you select, the player will skip over certain scenes, playing the version that you choose from those available on the disc. To prevent your setting from being changed, you can select your own personal identification number. PCM (Pulse Code Modulation) The digital audio signal format used for Compact Discs. Digital outputs on DVD players are often labeled "AC-3/PCM" because they can send either the AC-3 (Dolby Digital) bitstream from a DVD, or the PCM bitstream from a CD.   Perceptual coding A type of data compression used in recent digital audio and video formats. Audio examples include Dolby Digital and MiniDisc's ATRAC; video examples include digital satellite TV and DVD. This approach is based on sophisticated research into how we perceive sounds and images. Perceptual coding omits "imperceptible" sound and picture data which is redundant or which is judged to be masked by similar information. In the case of DVD, by "throwing away" a lot of redundant and unnecessary information, it's possible to fit multiple versions of a movie on a single 5-inch disc. Region codes The movie industry insisted that the DVD standard include codes which would limit playback to a specified geographical region. This was done because theater and home video releases of movies do not occur simultaneously worldwide. For example, a movie may be released on video in the U.S. just as it's first appearing in theaters in Europe. DVD players have a built-in region code lockout feature, while the DVD discs may or may not contain a code (region codes are optional on DVD software). A player will be unable to play a disc that has a different region code. Discs may contain codes for more than one region, or may not have any code, which allows them to be played on any player in any country. The region code for USA/Canada is "1". Signal-to-Noise ratio (video) This ratio is a measure of the content portion of the video signal in relation to the noise in the signal. As with audio, video signal-to-noise is measured in decibels (dB). The way the decibel scale works, if component A has a signal-to-noise (S/N) ratio of 20 dB and component B has a S/N ratio of 30 dB, component B will have ten times less noise in the signal than component A. Basically, a S/N ratio tells you how "clean" a video signal is. Because of the way they process signals, digital video formats like DVD and digital satellite TV are extremely clean. A standard VHS VCR may have a S/N spec in the low 40s; a laserdisc player, the low 50s. DVD is rated to deliver a S/N ratio of 65 dB!

Mick Evans 1999-2001

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