How to... buy a DVD recorder

DVD recorders are the 21st Century's equivalent of the VCR, but while virtually every VHS tape would work in your machine, it's not the same with DVD players or recorders. With DVD+R, DVD-RW and DVD-RAM formats, VR modes and dubbing options, choosing a DVD recorder can be a hit-and-miss process. Brands and model numbers come and go, so in this 'how to.' article we aim to guide you through the technology points you should consider.

Q. Are all DVD recorders the same?
A. Hardly, but it's not simply a matter of price or quality. Most DVD recorders are capable of very good picture and sound quality but vary in format compatibility, their ease of use, and the inputs and outputs they possess.

Q. Should I buy a multi-format recorder?
A. These are a good idea - the more types of disc that your machine can record on, the better. This will give you extra choice when buying blank discs and give you added flexibility in what you can do with your discs afterwards.

Q. What are the main differences between blank disc formats?
A. There are five main types, excluding the next-generation High Definition DVD (HD DVD) and Blu-ray discs that are due to appear in 2006.

Current disc types fall into two kinds: write-once or rewritable. Write-once discs can, as their name suggests, only be recorded on once and they must be finalised (like CD-R) before they can be played back in the majority of DVD players. Write-once discs come in two different formats, namely DVD-R and DVD+R. DVD Recorders normally accept one of these two, sometimes both, though in practical terms they are almost identical. Blank discs are cheap and recordings work in almost every player.

Rewritable discs come in DVD+RW, DVD-RW and DVD-RAM flavours. They can be erased and reused at least hundreds of times. DVD+RW is the most popular, easy to use and compatible in many players, though editing is somewhat limited.

The DVD-RW format is similar, but it can be formatted in two ways. 'Video mode' is like DVD+RW (though not quite as good for compatibility in players). 'VR mode', meanwhile, enables much more editing but discs are less likely to work in other players. A few dual-format ±RW recorders exist, mostly from Sony, but manufacturers tend to follow a 'plus' or 'minus' allegiance.

DVD-RAM is the most sophisticated and expensive type of standard blank DVD. It behaves like a small hard drive and can be edited or rewritten thousands of times and even played while recording. Some DVD-RW recorders also allow this, but only in 'VR mode'. However, DVD-RAM discs are unplayable in the vast majority of today's DVD players.

Q. Can blank discs be double sided or double layered?
A. Yes. DVD-RAM discs are often double sided, doubling their capacity. However, you have to turn them over manually. Double-layered DVD+R and DVD-R discs are now on sale, which also increase capacity and don't need turning over. Picture quality dips beyond about 2-3 hours on normal home-made DVDs, so these new developments help improve this. DVD+R was the first to go DL, therefore blank discs are relatively more affordable and available.

Only a few current recorders are compatible with DL blanks, such as Sony's RDR-HX510 for DVD+R and Pioneer's DVR-630H for DVD-R. Playback shouldn't be a problem on typical machines as DL discs mimic commercial DVDs. Dual-layered rewritable discs are being developed, but by the time they are established, much higher capacity HD DVD and Blu-ray systems are likely to be in shops (albeit with a hefty price tag).