Today's DVDs can't store or play HDTV movies and video because they were designed when standard definition was "good enough." Three changes have to happen for you to get HDTV from a DVD:
- DVD discs need more storage space.
- DVD players must be able to read these new DVD discs.
- DVD players have to outputHDTV signals.
Fortunately for HDTV addicts, the major players in the DVD industry are working furiously to develop high-def systems. Unfortunately, these companies have taken separate (and incompatible) paths to DVD HDTV nirvana.
You need a new DVD player for the following HDTV formats. However, the promoters of these standards promise their new DVD players also will be compatible with your oldDVDs.
Blue-laser systems
One way to increase DVD capacity is to switch to blue-lasertechnology. Blue lasers can read smaller pits in the DVD disc than red lasers (because a blue laser has a shorter wavelengththan a red laser). Smaller pits mean more pits (and data) fit on a disc.
You can find a couple of competing blue-laser standards on the market, Blu-ray and HD-DVD.
Blu-ray
The largest group of companies supports a blue-laser system called Blu-ray. The Blu-ray bandwagon includes Sony, Panasonic, RCA, Pioneer, Philips, Samsung, and LG.
A single sided Blu-ray disc can hold up to 25 gigabytes of data on a single layer (50 gigabytes on a dual-layer disc), which is more than enough data to handle most movies in HDTV resolution.
HD-DVD
High-Definition DVD (HD-DVD) is a blue-laser system supported by Toshiba, NEC, and the DVD Forum (an industry group that promoted the original DVD format). HD-DVD systems use a blue laser with larger pits in the DVD disc than Blu-ray.
Larger pits should make HD-DVD discs easier to manufacture, but they hold less data than Blu-ray discs. To make up for it, the HD-DVD folks use more aggressive video compression technologies (like Microsoft Windows Media) so longer movies fit on a disc. Compression basically shrinks the amount of storage space needed by a video by discarding "unnecessary" bits of the video. This removal can cause some degradation in picture quality - how much you lose is subjective, and it depends on which compression system you use. A good compression system is nearly unnoticeable.
Compressed red-laser systems
Some manufacturers are looking into using video compression technology to fit HDTV signals onto red-laser (regular)DVDs. The discs would look like standard DVDs, but you would need a new DVD player todecodethese compression methods.
Compressed red-laser systems can make HDTV DVD movies in existing factories, without new equipment. It doesn't make much difference to you, unless using the same factories lowers what you have to pay for HDTV DVDs.
The big studios making the DVDs themselves see the benefits of HDTV DVDs, though:
- Time Warner supports a red-laser system called HD-DVD9, which uses Microsoft Windows Media compression system.
- A group of manufacturers in China have developed the EVD compressed system.
