What is DVD?

DVD originally stood for Digital Video Disc, but since it can be used for audio and as a medium to bust the 650Mb limit on compact disc, it now stands for Digital Versatile Disc.

DVD encompasses video movies, data (DVD-ROM), and audio.

(Click here for a page of explanations of the underlying technology.)

The most obvious advantage is the total length of time available: two hours of video on the same form factor as the old CD (over eight hours on a double-sided, double-layer disc), and a maximum capacity (at present) of 15.9Gb: that's equal to 25 CDs.

Until they produce an economic DVD recorder, DVD won't be much of a threat to VHS (though there's a huge potential rental market waiting to be satisfied out there), but it could impact the small but significant laserdisc market (35,000 titles, playable on seven million laserdisc players throughout the world, compared with a mere half million players shipped in US, though Dataquest is predicting a 33-million player user base by year 2000). The technology is totally different: laserdisc is analogue, the sound is usually FM, while DVD is digital. The laserdisc is 12in in diameter; DVD is 4.7in. Most laserdisc players require you to turn double-sided discs over halfway through, but while some DVD players require this, double-layer technology makes this unnecessary on most of the players being sold today.

There's no question: DVD is superior to laserdisc.

Because the audio DVD format is still not entirely decided (and probably because companies are too mean to reauthor and remaster product originally destined for CD, or even vinyl) the full capacity of the disc is rarely taken up by its musical content. A recent "DVD Space Spectacular", for instance, contained only two works: Thus Spake Zarathustra, by Richard Strauss, and The Planets, by Gustav Holst, plus rather cheesy still visuals, and on-screen notation of the music being played.

You will seek in vain for any DVD of all the symphonies of Beethoven on a single disc, and while there are some single-disc video recordings of opera, nobody yet has grappled with the idea of putting all of Rossini (or Wagner's Ring Cycle) on to a single disc.

This is amazing, when you consider that you can buy a pirated MP3 disc of all the hits of everyone from the Beatles to Pink Floyd on a single CD at most computer fairs. The sound is sub-CD quality, granted, but as usual the biz is missing a golden opportunity here, leaving the market open to the pirates and bootleggers.

Things are a little brighter on the DVD-ROM side. Microsoft recently issued their multi-CD Developers' Network collection on a single DVD disc, and the three-CD Encarta 99 reference collection is available on a single DVD in US. UK release is promised for later in 1999.

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Regional encoding and other problems

[The six regions]
[ Buying a US player]
[ DVD on a PC]
[Copy protection]
[ DVD-RAM]
[CD-R & CD-RW]

Though US produces more titles in DVD format than UK, you can't just order them and play them on your PC or (if you've bought one) DVD player, since the movie companies have regionalised their releases, so that a Region 2 player (Europe) won't play a Region 1 (US) disc.

The six regions are:

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

There is also the PAL/NTSC problem familiar to anyone who's ever bought a video tape on a visit to US only to find that it won't play in UK (unless you've got a multi-standard VCR and/or TV).

A solution could be to buy your player from a US mail order company, like Earthstations.Com. Typically, you can expect to pay $345.98 for the Panasonic A-110 DTS/DD DVD Player, plus $75.98 and whatever duty and VAT the Customs & Excise boys decide to levy on you.

According to Jim Taylor's DVD FAQ (from which much of the information on this page was taken), "If you buy a player or drive from outside your country (e.g., a Japanese player for use in the US) you may not be able to play region-locked discs on it." However, it's not clear if he means that you wouldn't be able to play Region 2 (Japan and Europe) discs on a Region 2 player imported to USA (it would be interesting to know how this could be achieved), or the fairly obvious restriction that if you buy a Japanese player you won't be able to play US Region 1 discs on it.

It is possible to tweak a UK-bought player so it pretends to be either a Region 0 or whatever region you want to be, but this is not an easy task. Some movie companies have encoded their discs so that they won't play on a Region 0 player.

Most UK players will play either PAL or NTSC movies.

If you have a PC, some of these problems will not apply, notably the NTSC/PAL problem. It's easier to change the Region, but your system may not allow you to switch regions all the time.

You may find that you can only switch regions a few times (typically, five) after which it will stick in whatever region configuration you chose last.

In addition to the DVD disc player (obviously) you will also need an MPEG decoder to actually display the image on your monitor. An increasing number of new PCs are now shipping with built-in DVD player, since this will also play CDs and CD-ROMs, but check before you buy to ensure that it will also play DVD movies.

The movie companies are also building in copy-protection, since a DVD disc is a virtually perfect master for bootlegging, though some may allow you to make a single tape copy (rather like the fact that you can't make multiple copies of a DAT copy of a CD audio disc).

You can buy DVD-RAM writers, which will allow you to save to the massive capacity of DVD for use as an archive medium. What you won't be able to do with DVD-RAM is to use it as a VCR, though according to Jim Taylor, "In June 1997, Hitachi demonstrated a home DVD video recorder containing a DVD-RAM drive, a hard disk drive (as a buffer), two MPEG-1 encoders, and an MPEG-2 decoder. No production date was mentioned."

If you want to read CD-R or CD-RW discs, you need to ensure the DVD drive is one of the new "Multi-Read" units, but even then it may have problems with CD-R, because the wavelength of light used in the two formats is different. CD-RW should be fine.

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Hardware

Probably the best all-round DVD player in UK is Pioneer's DVD-717, which produces great sound as well as superb video images. (The part numbers quoted in this brief overview are for UK versions: hardware for other countries may be numbered differently.)

Hifi critics playing CDs on this player were particularly impressed by its audio performance.

Pioneer also make a great DVD-ROM drive to be fitted internally in your PC, and is producing players which will also handle laser discs.

Panasonic make a remarkable portable player (pictured at top of page), the DVDL10, which delivers remarkable results, considering its size (160mm W x 160mm D x 43mm H) and 910kg weight. The 14.5cm LCD screen gives 500line quality definition, and the sound through the twin built-in speakers is Linear PCM - 24 Bit, 96KHz, with a claimed frequency response of 4Hz - 44KHz (Audio S/N:115dB).

It's a pricey toy (about $1300 stateside, official UK price not currently available, though the Tottenham Court Road street price is over £1000).

There's Digital Output for MPEG2/Dolby Digital Decoder, so you could hook it up to your home system. There's a remote to add to the pile of remotes by your TV set. Claimed battery life on the road is two hours.

Basically, if you're not too much of a videophile or audiophile, most hardware will perform more than adequately, so shop around. (If you want to play CDR or CD-RW discs, then make sure you get a MultiRead model.)

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Audio

Audio is encoded on DVD several different ways, depending mainly upon the system used for the original (obviously, you won't get Dolby-encoded surround sound on a mono soundtrack to a prewar classic movie).

All DVD players have either a built-in Dolby Digital (AC-3) or MPEG audio decoder, or both. The decoder translates multi-channel audio into PCM audio, which is fed to the digital output and/or converted to analog for standard audio output. Most players have only a 2-channel-output decoder, but some provide 6-channel output. Up to eight tracks of digital audio (for multiple languages, DVS, etc.) can be on each disc, each with as many as 8 channels.

The DVD Consortium has released draft standards for DVD audio-only discs, and the final version is expected soon, with DVD-A products due to ship later in the year. Playing times will be between 75 and 135 minutes of 6-channel 96kHz/24-bit audio on a single layer or between 120 and 140 minutes of two-channel 192kHz/24-bit audio (compared with 44.1kHz at 16 bits for current CDs). Both 8cm and 12cm discs are allowed within the specification. DVD hardware produced before the finalisation of the standard may be unable to play the new discs.

To deal with this eventuality, Sony and Philips have proposed a Super Audio CD format based on Direct Stream Digital (DSD) with sampling rates of up to 100 kHz. SACD discs will have two layers, one that will play in existing CD players, plus a high-density layer for DVD-Audio players.

Meanwhile, current DVD discs already provide superlative sound, utilising either 1 to 5.1 channel Dolby Digital, formerly known as AC-3 (the ".1" is a low-frequency effects channel carrying an emphasised bass audio signal and connected to a subwoofer), 1 to 5.1 or 7.1 channel MPEG-2 audio, or 1 to 8 channel PCM.

Any disc with Dolby Digital or MPEG-2 audio will be decoded automatically and downmixed to Dolby Surround output for connection to a regular stereo system or a Dolby Surround/Pro Logic system.

Some discs may have more than one Dolby Digital version of a soundtrack, for instance a 5.1-channel track and a track specially remixed for stereo Dolby Surround.

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