Alphabet swamp

CDs, DVDs, SACDs, DVD-Audio, DVD-RW, DVD+RW, DVD-Ram

But no technology stands still and now manufacturers are wrangling over the best way to improve the digital discs. Format wars are breaking out in almost every sector where the discs are used.

Unless consumers are careful they could find themselves buying audio or movie discs that look like the old ones but can only be played on certain machines.

If some of the formats wither and die, consumers could find that suddenly they cannot buy any discs to play on the expensive device squatting next to the stereo system.

When CDs first went on sale, many hi-fi buffs complained that they did a bad job of preserving the richness of recorded music. Purists remained wedded to their slowly deteriorating collections of vinyl records.

Spoilt for choice? Things are simple nowadays

It is true that compromises have to be made to fit music on to a CD. The music recorded on to these 650-megabyte discs is sampled several thousand times a second, and some frequencies that the human ear cannot pick out are simply dropped.

To make digital recordings at all, these kind of choices are inevitable, said Eric Kingdon of Sony UK.

"The only way to achieve a perfect digital stream is to sample it at infinite speed and measure it at infinitesimally small values," he said, "but we just cannot do that."

Now, a wrangle is developing over the best technology for improving the ability of digital discs to capture music.

Audio assets

Sony and Philips, the joint developers of the CD, have come up with a format called Super Audio CD that samples the music being recorded more often and preserves some of those sounds that are usually discarded.

The pair are promoting this standard for several reasons. First, they have come up with a neat way of encoding the sampled stream of music that makes it possible to remove quite a few components from music players. The result could be smaller, lighter, cheaper devices.

Remember when?

Secondly, these higher capacity music discs are easier to protect with watermarks and other security technologies. It is arguable that if music on CDs had not been so easy to copy then Napster might never have arisen and the recording industry would not be faced with the problems that are currently bedevilling it.

Finally, some of the impetus for change may also come from the fact that the patents on CD technology will expire soon, which means lower licensing revenues for Sony and Philips. New technology means new licences and more cash.

In the opposing camp are the companies backing the DVD-Audio discs that attempt to improve the sound on movie discs. The DVD Forum, which oversaw the development of the standard that crams a movie on to the 4.7-gigabyte capacity discs, is keen to improve them further.

Tests by "golden eared" specialists say that DVD-Audio sounds better than ordinary CDs, but not as good as Super Audio CD.

Different audiences

Unfortunately, and this is where it starts to get complicated, both DVD-Audio discs and Super Audio CDs need new machine to play them.

There is enough room on the 4.7-gigabyte Super Audio CDs (SACDs) for the old CD-style recording, giving you the chance to use your existing player until you have enough SACDs to justify a player just for them.

SACDs are already starting to appear and to date more than 325 titles have been produced using the format.

You'll also need a new DVD player for DVD-Audio discs. Players are starting to appear that can play SACDs, DVDs and DVD-Audio discs, but they tend to be expensive. You will not be able to play either SACDs on a dedicated DVD-Audio player or vice versa.

Mr Kingdon from Sony UK says there is no format war developing here because the two technologies are intended for different audiences. Super Audio CDs are for music fans and DVD Audio is likely to only be used on movies.

Recording wrangle

But that is just the start of it. A real format war is being waged over rewritable DVDs that are eventually intended to take the place of video tapes and recordable discs for computers.

Japanese electronics giant Pioneer and another 11 companies are backing the DVD-RW format that can record up to six hours of VHS quality TV on a CD-sized disc that has the same 4.7-gigabyte capacity as regular DVDs. It is likely that existing DVD players will be able to play these discs but obviously not record programmes on them.

In the opposing camp are the likes of Sony, Philips and HP, who are backing the 3-gigabyte capacity DVD+RW format. This latter standard is not fully endorsed by the DVD Forum and is being pushed by an ad hoc group of companies who want to see it work.

The official recordable DVD standard is known as DVD-Ram and once finalised will produce discs with a capacity of up to 100 gigabytes.

In the short term, it is unlikely that any DVD drive that can record in one format will read discs produced in another. All drives are likely to play older types of discs such as rewritable CDs and ordinary music CDs or CD-Roms.

Meanwhile, those vinyl fans who held out against CDs will doubtless carry on avoiding dust and scratches, blissfully ignoring the alphabet swamp rising in the High Street.