What is DVD+RW?

David Dorn explains what DVD+R and DVD+RW actually mean for you, the user

DVD+RW, DVD-RAM and DVD-RW are all rewritable DVD formats, however, only DVD+RW is designed from the start to be fully compatible with existing DVD-ROM drives and DVD-Video players. This means that a DVD+RW disc recorded in a DVD+RW recorder can be played in virtually all DVD-Video players or DVD-ROM equipped PCs, and that any DVD+RW disc recorded with data on a PC DVD+RW drive can be read by most DVD-ROM drives.

The other formats do not offer this level of compatibility, or only provide for a very limited 'compatible mode'. This might be limiting the recording to only 1 hour of video.

DVD-RAM uses a totally different kind of physical recording method, which is absolutely incompatible with DVD (hence, it can hardly be called 'DVD'). No existing player will be able to read DVD-RAM discs, even if you use the newer version without a cartridge housing.

And DVD+R?

DVD+R (DVD+Recordable) is defined as a subset of DVD+RW. Using DVD+R write once discs, which ought to be a lot cheaper than DVD+RW discs, you can record material in the same way as with DVD+RW discs without the ability to erase the disc or re-record onto them. DVD+R discs can be recorded by any DVD+RW PC drive, except for the first generation of DVD+RW PC drives (manufactured before April 2002). First generation DVD+RW video recorders need a firmware upgrade - of which few are currently available (mid July 2002). DVD+R, like DVD+RW, has a capacity of 4.7 GB and there'll be only one format of blank disks

Can I overwrite DVD+RW disk?

Indeed you can - up to 1000 times, according to manufacturing tests. Of course you cannot overwrite DVD+R disks, as they're write-once. Although that doesn't actually mean you can only record to them once, in practice, if you're using them for video, that's the effect.

What if I've got a 'First Generation' drive

At the time of writing, you're pretty much stuck with DVD+RW functionality - the first generation drives do not support DVD+R disks. More accurately, the firmware does not. It may be possible to upgrade the firmware via a flash download on some of the drives, although some manufacturers have created a swap-out scheme to replace first generation with DVD+R capable drives.

Is it worth going for?

If you're heavily into video - and this effectively means digital video - then DVD+R/RW is a very suitable medium for your video projects. Current pricing on DVD+RW blanks is prohibitively high, though at something around £10 per disk. DVD+R, though, is likely to be much more cost effective, and less prone to accidental over-writing. Once the market has settled down, a DVD+R capable drive will be a sound investment for the video buff. Until then, it's possibly better to stick with Mini DV tapes.

David Dorn