DVD writing: The burning issue

Most home computer users are familiar with the concept of storing information on a CD. They have a much greater capacity than floppy disks so you can use them to store large files without cluttering up your hard disk.

DVD goes one stage further, storing even more data. That means you could use a single DVD instead of a stack of CDs. DVDs also change the types of data you can store. CDs made it feasible to store high-resolution photographs for the first time but, with DVD, you can store a high-quality, feature-length video.

If you've recently bought a PC, there's a good chance it has a DVD writer built in, but if your PC is a bit older you can easily buy one for about £50 and many writes come bundled with DVD-creation software. Although the hardware and software for burning DVDs is cheap, there is plenty to learn if you want to make the most from them.

Here we investigate the advantages of burning DVDs, take a look at the thorny issue of compatibility, and show you some of the benefits to be gained from using specialist DVD-burning software.

Introducing DVD
DVD started out as a direct replacement for VHS video cassettes, and was called Digital Video Disc. Today, since it can be used for so many different jobs (including high-quality audio and data as well as video), it now stands for Digital Versatile Disc.

To computer users, though, the most important aspect of DVD must be its storage capacity, and at 4.7GB it's huge. A DVD can hold more than seven times as much data as a CD, or as much as 3,357 floppies, which stacked on top of each other would be more than 11 metres tall. And this is just for ordinary DVDs; the up-and-coming, dual-layer discs hold even more - 8.5GB to be precise.

Although these figures might seem impressive, they're not quite all they appear. In computer circles a gigabyte (GB) is the figure you end up with if you multiply two by itself 30 times - it works out at 1,073,741,824 bytes. But technology companies think this is rather unfriendly language and difficult for consumers to understand - not an unfair point. So they round down the figure to 1,000,000,000 bytes.

The upshot of all this is that the discs are only 93 per cent as large as you might expect. This applies to all disk measurements, whether they're CDs, floppies or even the hard disk in your computer, so DVD manufacturers aren't short-changing you as such. After all, what's seven per cent between friends?

No matter how you look at it, there's no denying DVDs are big. So why might you want to use these monsters of the storage world? How can you possibly consume so many bytes? Let's investigate.

Protect your files
Backing up might not be the most exciting topic and it's one that too many people brush under the carpet. But if you don't want to risk losing precious data, it's a chore worth doing. With DVD, backing up is hassle-free, especially with software such as Roxio Easy MediaCreator 7 (£69.99), which allows backup as well as supporting more creative uses of DVD. With its one-touch facility, creating a backup requires no more than a single click of the mouse.

Even if you've created a backup, though, restoring your computer after a crash isn't as easy as you might hope. You can easily restore all your user files from the backup disk, but it could take a long time to reinstall all your applications and configure Windows as you like it. The solution is to copy a disk image - that's every single bit rather than individual files - to DVD.

Since hard disks now have capacities measured in hundreds of gigabytes, this image might not fit on a single DVD, but software such as Norton Ghost 2003 (£39.99) allows the image to span multiple disks.

The write stuff
Now you've finished with the dull but worthy stuff, let's create some more entertaining discs. DVD-burning software lets you create copies of CDs or other DVDs you own - but a word of warning on copyright. It is illegal to copy material unless you have the permission of the copyright owner.

Complying with this law is easier now since most commercial DVDs are protected by digital rights management (DRM) technology which prevents you making a copy. So if you want to copy home movies, Roxio's Easy DVD Copy (£20) lets you copy data disks, music CDs and any video DVDs that don't incorporate copy protection.

Next you can use a DVD writer just as you'd use a CD writer to write individual files to disk, either for archive purposes or to send to a friend. Any of the general purpose DVD writing packages - Nero Burning ROM 6 (£60), for example - provide the means of doing this with more advanced features built in.

The files you write to DVD don't have to be just data files for use on a PC - you can also write files to disc that can be read by home entertainment systems. You could put together albums of photographs, complete with menus, which can be displayed on your TV via a DVD player. This is a feature of many DVD authoring packages, such as Sonic's MyDVD (from £28). Bear in mind, though, that unless your photographs started life digitally, scanning hundreds or thousands of slides or negatives is a serious undertaking.

Similarly, you could create an absolutely huge music compilation on DVD, although it will only play on your PC or a DVD player. While the movie business has been very quick to protect its DVD movies with DRM software, the music industry is still selling plenty of CDs that you can copy. OK, technically speaking it's criminal, but we doubt the police will raid your house at dawn if you're making a compilation for your own use or a copy to keep for playing in the car. Just don't give or sell them to others.

One thing DRM will stop you doing, however, is making copies of any music you have bought from legal downloading sites such as Napster and iTunes.

And how about putting together your own video disk? Ulead's DVD MovieFactory 3 (£26), and CyberLink's Power2Go 3 ($40/£22) are just a couple of the packages that enable you to mix and match any combination of video, audio and still images onto a single disc. You can even import footage straight from your video recorder.

Now the sky's the limit. What about transferring your family tree to DVD, with images and possibly film footage? You may be interested to know that Pathe News sells parts of its huge archive of historic footage, so if a relative of yours played a part in history, such as the First World War, you could link out from the family tree to a clip showing an appropriate scene.

Where will they play?
The world of DVD is one of confusing abbreviations such as DVD-RAM, DVD+R and DVD-RW. You can read what they all mean in DVD Standards (below), but what you really want to know is: how can I tell whether the DVD I create can be used in the DVD player connected to my television?

The short answer is that most modern players will play everything except DVD-RAM discs, although some makers now welcome this standard too. If you have an older DVD player, it's unlikely to play discs that can be rewritten over and over again (these always have 'RW' as part of the standard name).

Many DVD writers are now dual-standard, meaning they will play both plus and minus formats, so if you're planning to upgrade and want to view your DVDs on the television, make sure to ask about that before buying.

Most industries would leave it at that, but not the electronics industry. Just as people had got their heads around writable and rewritable discs, in the plus and minus formats, along came a new contender: dual-layer. This new format for DVD adds extra storage to each disc, and the good news on the compatibility front is that there's only one type available, and that's DVD+R.

Enjoy this moment of simplicity while it lasts, as the DVD-R standard is expected to be found in some new DVD burners from early next year. Most players will be able to read both, unless, again, you have an older DVD player. And don't rush out to buy stacks of the new dual-layer discs to burn on your existing burner because - surprise, surprise - they won't work. The new discs need specially designed burners.

Speed and media
CDs can take a long time to burn so, since DVDs are seven times as large, you might be concerned that they'll take forever to write. The good news is that DVD drives are much faster than CD drives. A complete 4.7GB DVD will take 53 minutes to burn at the so-called baseline speed.

Fortunately, all today's drives have speeds measured in multiples of that speed so a drive that claims an 8x speed for writable media (this is typical, although rewritable media is usually slower) will create a disc in around six and a half minutes.

This assumes the drive is working flat out, which often isn't possible. The PC might not be able to supply the drive with data at this speed and the discs can't always handle too much data at once - especially cheap, unbranded CDs and DVDs. As we saw in our feature on branded versus bulk-bought discs, although these represent excellent value for money (big name discs can cost seven times as much), they sometimes struggle at the highest writing speeds.

Plus, we have no reason to believe they're not as reliable - after all, only time will tell - but it would be wise not to rely on them for storing important archive material. So how long will a rewritable disc last? Under ideal conditions, experts believe it will have a 30-year lifespan.

DVD standards explained

DVD-RAM
These discs can be written to over and over again like a hard disk, so are suitable for general computer storage. However, since they can't be read by most domestic DVD players, or even by the ordinary DVD-ROM drives in PCs, they're a specialised solution.

DVD-R/RW
DVD-R discs (writable) can be written to just once; DVD-RW (re-writable) can be written to, erased and rewritten many times. Both can be read in the majority of DVD-ROM drives and domestic DVD players.

DVD+R/RW
DVD+R and DVD+RW are competing standards to DVD-R and DVD-RW respectively. Like the 'minus' standards, they can be read in the majority of DVD-ROM drives and domestic DVD players.

Dual Layer
Dual layer discs have a second semi-transparent recording layer which almost doubles the capacity from 4.7GB to 8.5GB. To date, the only writable or rewritable format to incorporate dual layer support is DVD+R. Others will follow.