First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.
- — 18 October, 2005 11:16
- DVD vs. CD
- Capacity confusion
- Questions to ask yourself
- Comparing DVD standards
- Who supports which standard
- Other Considerations
Looking to produce your own DVD movie masterpieces? How about backing-up all those unprotected files? If the answer's yes, you're probably looking for a DVD writer to do the job. But what makes a top notch DVD writer?
To help make sense of the multitude of DVD hardware and standards, this DVD Writer Buying Guide will explain the technology behind DVD writers and take a look at the various types of media. We will take a look at the technology of tomorrow, with previews of what's in the DVD pipeline.
We'll also take you through the technical questions you should ask about before buying a DVD writer, and delve into the additional equipment you might need to connect one to your system.
DVD vs. CD
DVD stands for Digital Versatile (or Video) Disc -- a high capacity multimedia storage medium that has the same physical dimensions as a Compact Disc (CD). It can store up to seven times more data than a CD though, thanks to finer grooves, smaller markings and different laser technology. Like CDs, DVDs store data in microscopic grooves (tracks) running in a spiral around the disc. DVD drives use laser beams to scan these grooves: minuscule reflective bumps (called lands) and non-reflective holes (called pits) aligned along the grooves represent the zeros and ones of digital data.
But that's where the similarities end. DVDs use smaller tracks (0.74 microns wide, compared to 1.6 microns on CDs) as well as more sophisticated modulation and error correction methods. Thankfully, however, the majority of DVD drives and players today support CD formats as well.
The result is that a single-layer DVD can store up to 4.7GB -- up to two hours of video -- on a single-layer disc. A CD can only hold 700MB of data (80 minutes of audio). DVDs also come in double-layer format, which can hold up to 9.4GB. One of the layers on a double-layer disc is semi-transparent so that the laser can focus through it and read the second layer.