Multimedia: Stay home to tour a gallery, learn guitar: Steve Homer examines the growing range of applications for CD-I and reports on the machines

DO YOU want to make the perfect apple tart, learn to play the guitar, get into shape, tour a museum, pit your wits against fiendish alien hoards, discover where Genghis Khan was born?

Well, you could sit and watch television for the rest of your life and hope the answers arrive. You could play on a games machine - until you got bored. You could watch an instructional video tape and try to find the part you needed. Alternatively, you could invest in a home multimedia player.

A new box has joined the hi-fi, the video recorder, the video games machine and the satellite television controller in some 70-100,000 homes in the UK. It is an interactive entertainment centre called a CD-I machine.

CD-I discs work a bit like books. You can flip through and look at the part you want to. The discs contain text, pictures, sound and animation all linked together. This means that you can explore the information stored on a disc in your own way, at your own pace.

Take learning to play the guitar, for example. The disc first helps you to tune your guitar by playing the right notes. With small movie clips it shows you where to place your fingers to play the various chords. You can then practise. You tell the player how fast to go and it can repeat the chords you are having problems with until you are happy.

On a museum disc you can explore different halls at your leisure or take a guided tour. For some exhibits there are demonstrations showing how the exhibits were made or work.

CD-I games allow you to play different roles. Children's titles can mix animation with learning and allow kids to discover spelling in an entertaining way.

Last year CD-I got another ability. It can now play VHS quality video from discs by adding in a pounds 150-cartridge. While this means you can play movies off disc, it also means video clips can be included in games, educational and entertainment titles. Music discs including video are likely to be very popular, although there are only a handful as yet.

But while CD-I dominates the market today in its specialist area, it faces a lot of competition. Firstly, games machines are becoming ever more sophisticated. Machines like Sega's Mega CD machine offer considerable interactivity but, to date, available titles have been almost exclusively games.

There are new challengers on the horizon. Nintendo is promising a system called Reality. Sega is developing a powerful machine called Saturn. Sony has a project called PS-X. All should arrive in the second half of next year. All are pure games machines but they will be very powerful and may dent CD-I's market.

The biggest threat to CD-I could come from an American system called 3DO.

3DO was designed essentially as a games machine but is now also being touted as a general interactive player and should be on sale in the UK in September.

So what should you do about buying a machine? If you want only to play games, then there are obviously the games machines. 'But if you want to play games, use reference works, play Video CDs and all the other things, you only have two choices, certainly for the next 18 months,' says Stuart Dinsey, editor of CTW, the interactive entertainment trade newspaper. 'You either have a Philips CD-I machine or you have a fully kitted out PC with CD-ROM drive, sound board and so on. That will cost you pounds 1,300- pounds 1,400.' However, the computer system does offer added flexibility.

Geoff Hoon is a self-confessed technology junkie. He bought a CD-I player for his family 18 months ago. 'I bought it mainly for the children. I'm a bit worried that Philips seems to be going more in the direction of games at the moment. That would be a pity because then it would be like all the other games machines.

'I think the appeal of CD-I is that it is a way of imparting information to children in an attractive manner which they like.' However, Mr Hoon admits he enjoys his CD-I golf game.

While he is a bit worried about other formats making CD-I obsolete, he is not too concerned. He says he will still be able to use his CD-I discs, use it for Photo CD discs to show family snaps on the television and it is an excellent CD-audio player.

Other formats may establish themselves, but with a top-flight CD player costing pounds 300-400 and a CD-I player only costing pounds 399 ( pounds 499 with video cartridge and one video title), if you want a CD player, it is worth at least considering buying a CD-I machine.