The DVD Decision

CD-ROM Drives triggered a revolution in the computer industry, but the only real change we’ve seen since their arrival is increased speeds. And speed only matters if you’re transferring vast quantities of data.

If you’re listening to music, a 4X drive is going to do as good a job as any other (except, perhaps, for a little digital re-sampling or searching between tracks). In fact, high speed disks can – due to spin up time – even slow down the transfer rate in the case of small files.

The only other interesting development in CD-ROM technology is that a number of manufacturers have attempted to make larger capacity disks, although most recorders and the majority of recording software don’t support them anyway. The result is that there is space for a new form of media, and that happens to be DVD. Isn’t DVD meant to be about movies and stuff? Yes, but there’s a lot more to DVD than movies.

For starters, there’s the issue of capacity. A DVD disc can hold 4.7GB of data. But this is just a drop in a much bigger ocean. DVD discs can also be dual-layered and double sided, which means that they can store even more data on a single disc. Indeed, you can store an impressive 17GB of data on a dual layered and double sided disc, blowing the average CD-ROM right out of the water.

Of course, you’ve already established vast collections of music and data on CD-ROM and you don’t want to throw them all out in the move to DVD. Fortunately – and this is one of the key strengths of DVD technology – all DVD drives are backward compatible, so you can still play your CDs and access your data on CD-ROM while using a DVD-ROM drive. This is critical to the DVD drive’s success, and without it, the DVD would simply be yet another media form. But it’s not, and if you ignore it you could find yourself left behind.

This all sounds like a worthwhile change, but DVD speeds also seem to be much slower than CD-ROM drive speeds. If you can store such large amounts of data, surely you’ll need faster drives? The problem is that this is much like comparing apples and oranges. Because DVD discs have a much bigger capacity, the tracks are placed much closer together so more information is read over a shorter space across the disc.

Furthermore, DVD drives spin a lot faster than CD-ROM drives; a 1X DVD drive spins at about the same speed as a 3X CD-ROM drive. With CD-ROM discs the tracks are further apart, so the DVD drive can increase its reading speed…often significantly. The result is that the speeds used in these two technologies are not entirely comparable, although there obviously is a relationship between the two.

For the DVD movie fanatic, speed is unlikely to make much difference. In fact, the only difference that you’re likely to notice watching a DVD movie on a faster DVD-ROM drive are smoother scanning through the movie and faster searching.

There are a number of other factors that are worth discussing, most notably the drive itself. Unlike a set top or standalone DVD player, a DVD drive can not, on its own, play DVD movies. To do this, you need an MPEG-2 decoder of some sort. Until recently, the most common way of doing this was to use a decoder card and DVD player software.

This is changing, however, and many of the more up-market graphics cards now support DVD and are capable of performing MPEG-2 decryption (with the help of specialized software). So, you may well discover that your graphics card or DVD drive comes with a ‘soft’ DVD player. Whatever the case may be, ‘soft’ DVD players use system resources, so count on needing a fair amount of RAM and a reasonable processor.

More importantly, you’ll need a good sound card and a graphics card with a fair amount of dedicated memory. At least 16MB. You may discover that you can use your DVD drive without a decoder card, but you will miss out some of the features that a good decoder card can offer.

So what’s in a decoder card? Well, if you don’t have a DVD compatible graphics card, a decoder card is essential. Furthermore, if you don’t have a graphics card that can provide high resolution graphics, a decoder card will ensure that you can still watch your movies at high resolution and in full 32-bit color.

With a good DAC (Digital to Analogue converter) on the card you can expect sharp, clear images at high refresh rates. The dedicated hardware also frees up resources, taking the load off your processor, RAM, and graphics card.