DVD MADE SIMPLE

New technology often comes with a host of problems and formats to grow accustomed Roger Kirkwood walks us through the DVD minefield

DVDs are supposed to be simple. You get a shiny plastic disc, place it into a DVD writer and ‘burn’ data, such
as video, onto it. Then you put it in any DVD player, sit back and reach for the popcorn. Unfortunately, it’s not
quite as simple as that. There are several different standards all competing for market share, rather like the old struggle between VHS and Betamax.

IN THE BEGINNING

Compact Discs were first introduced in 1983 and revolutionised both the music and data storage markets. However, there’s a problem. The limited capacity (by today’s standards) of 650MB means they are of moderate use for storing video, or for that matter storing large chunks of data.

Enter DVD, a technological re-working of the humble CD, also influenced by the dinner plate-sized videodisc. The basic standard was finalised in 1995 with products first appearing in 1997. Each disc can hold 4.7GB on a single layer and provides a convenient and high-quality distribution method for video, which is stored in MPEG-2 format, allowing DVD films to take the market by storm just as music CDs did before them.

However, the content of films is pre-installed at a factory, so does not suffer from the formatting problems posed by user-created discs. It’s when DVDs are combined with multi-media laptops and DVD-burning drives that the possibilities your own home movies. These in particular would benefit from wide compatibility, allowing you to play your master-pieces on a set-top DVD player. This is where the thorny issue of formats comes in: what will the various standards allow?

TANGLED WEB

As with any new recording technology, various formats appeared as different manufacturers promoted their own really open up, including storing computer files and making standards in the hope of cornering the market, and in the case of DVDs, the opportunities for volume sales and royal-ties are particularly enticing. As the competing formats grabbed a foot-hold, manufacturers have been forced to make devices that support multiple formats to ensure they’re useful and attractive to consumers. The encouraging news is that compatibility problems are now few, although the chances of a disc recorded at home not playing on a certain device is higher than with commercially recorded discs, which use a different process. 

 
Today, many DVD burners are capable of operating with several formats, and you can find a wide variety of combinations supported. Some drives record in both the plus and dash formats (variously called DVD+/-RW, dual-format or combination). The DVD Forum has introduced the ‘DVD Multi’ logo to indicate a player or recorder that can handle all three of its formats: DVD-R, DVD-RW and DVD-RAM. Drives have also begun to appear that combine the Forum
and Alliance formats to support all five burning techniques. Although multi-format drives cost more, they offer greater flexibility and enhanced security for the future, especially since the relative popularity of the competing formats has not fully settled. Most DVD writers will also write to CD-R and CD-RW discs.

COMPATIBILITY – THE FULL STORY

Even though in theory there are set-top DVD recorders that support one or more of the formats, in practice you may encounter a problem. Pre-recorded discs that you buy from a shop are created with a different process to that of home DVD burners, and the discs have a different reflectivity. Unfortunately, some players haven’t been designed to allow for this, and several Internet sites maintain device compatibility lists. You also have issues of media (disc) quality and player tolerance. Still, recordable disc compatibility with set-top DVD layers is better than 80 percent. Write-once discs still enjoy slightly wider compatibility than the RW types, making them a better (and cheaper) choice if you’re distributing your own content.

WHICH FORMAT IS RIGHT?

There are many who claim that DVD- is better than DVD+ and just as many who swear it’s the reverse, not least the Forum and Alliance themselves. The
bottom line is that functionally they are very similar, and both have broad compatibility with consumer DVD players. The one claim that can be substantiated is DVD-RAM is a more powerful format for computer data, since it can handle many more re-write operations and support drag-and-drop transfer at an OS level. It ‘s effectively like having a removable hard disc drive. It’s gaining popularity in set-top devices too because of the flexibility it gives for editing recordings. When it comes to choosing the right format, there’s currently little evidence to say which one will come out on top. Using the VCR analogy, where Betamax offered greater image quality, while VHS proved more economical, it’s possible to see that DVD-R will become the dominant format. However, we feel that the increased use of multi-format drives, which read all three competing formats will become more commonplace. In this way, users will be able to create and distribute DVDs regardless of the format.

And it doesn’t end there, because there’s now HD-DVD, which uses blueviolet lasers. Light from the current red lasers has a wavelength in the region
of 650nm, allowing it to pick out extremely small areas on a disc. However, blue-violet laser light has a wavelength of around 405nm, allowing the information it can read and burn to be even smaller and closer together. This will allow disc capacities to jump to 30GB per layer and beyond.
But don’t worry that your current DVD collection will be obsolete. The new technology is still a couple of years away and will no doubt be comparatively
expensive. This will leave the main focus firmly on our current DVD formats for years to come, and when you do switch, you can be sure the new drives
will still be able to read current discs.

DVD FORMATS

The different DVD formats you will see are: DVD-ROM; DVD-R; DVD-RW; DVD+R; DVD+RW and DVD-RAM. If the names seem familiar it’s because of their similarity to CD formats. There are also two formats for consumer electronics: DVD Audio and DVD Video. Recordable DVDs fall under two governing cRW and DVD-RAM, which is referred to as DVDamps that consist of consortiums of manufacturers. The DVD Forum promotes DVD-R, DVD-dash. While the DVD+RW Alliance backs DVD+R as well as DVD+RW – known as DVD Plus.

DVD-ROM
This is the computer equivalent of a DVD player, but it can read computer data as well as play movies and audio CDs. For some time it has been common to find DVD/CD-RW combination drives on laptops, which can burn CDs (CD-R), re-write CDs (CD-RW) and play DVDs (DVD-ROM).

DVD AUDIO AND DVD VIDEO
These are consumer formats for the distribution of music and film, offering superior quality and capacity to older technologies such ac CDs and VHS. To play DVD movies your laptop will need a software player to read the disc.

DVD-R
This recordable format is a ‘write-once’ technology, which means you can only record to the disc once and you cannot edit or replace that content later.
It first appeared in 1997 and used to have the widest compatibility with set-top DVD players. The discs come in two varieties, DVD-R for general use and a professional version called DVD-R for Authoring, but the general use version is the type available for laptops.

DVD+R
Introduced in 2002, this is an alternative write-once format. Functionally it’s similar to DVD-R and is also compatible with set-top DVD players. Backed by the DVD+RW Alliance.

DVD-RW
Backed by the DVD-Forum, it debuted outside Japan in 2001. The RW stands for rewritable, which means you can reuse a disc by copying over its previous content. This format is compatible with most players, but not as widely so as the write-once formats, and you must ‘finalise’ a disc before it can be played.
The discs are rated for around 1000 rewrite operations. Most DVD-RW drives can also burn in DVD-R format, and the Apple SuperDrive is a DVD-R/RW device.

DVD+RW
A rewritable format that’s functionally similar to DVD-RW, is reusable up to 1000 times and has similar compatibility with set-top DVD players. Because it appeared before DVD+R (2001), many of the older DVD+RW drives cannot burn in the write-once format, but all the new drives can do both. Backed by the DVD+RW Alliance, the newer plus standards are not as widely used as the dash formats, although they’re gaining a share in the market.

DVD-RAM
Backed by the DVD Forum, it was first available in 1998. Originally, the discs were housed in a cartridge, which provided a high degree of protection, but now they’re available without cartridges. DVD-RAM works with both Windows XP and Mac OS X, allowing it to work like a hard drive with a simple drag-and-drop operation. It’s the best solution for data storage, but this was at the cost of limited compatibility. In the past, DVD-RAM discs could not be played in set-top DVD players, but because of its flexibility for editing, many consumer players now come with DVD-RAM support.

DVD FORMATS AT A GLANCE

FORMAT	ADVANTAGES	DISADVANTAGES
DVD-ROM	• Can play on laptops and home DVD players	• Can’t write to it
DVD-R	• Recordable • Can play on laptops and most home DVD players	• Can’t record more than once
DVD-RW	• Recordable up to 1000 times  • Can play on laptops and most home DVD players	• Discs may not play on older or basic home DVD players
DVD+R	• Recordable • Can play on laptops and most home DVD players	• Can’t record more than once
DVD+RW	• Recordable up to 1000 times  • Can play on laptops and most home DVD players	• Discs may not play on older or basic home DVD players
DVD-RAM	• Can record up to 100,000 times • OS-level drag-and-drop editing	• Can only play on DVD-RAM compatible drives • Discs won’t play on older or basic home DVD players