A number of new digital video disc formats have arrived on the scene to bring us high definition video on disc. And it's about time. Recently, while shopping for a digital television, I had the you-need-way-more-than-just-this-TV conversation. It was eye opening to see just how much investment (not just money) it takes to get 1080i from start to finish in my entertainment center. The main players in the game right now are Blu-ray and HD-DVD.
Blu-ray
Blu-ray, also known as Blu-ray Disc (BD), is being jointly developed by the Blu-ray Disc Association (BDA). The BDA is a loose confederation of a number consumer electronics and PC companies - including Sony, Samsung, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips and others).
So, what is a Blu-ray disc? That's a question best answered by comparing it to traditional DVD's...
A single layer traditional DVD can store 4.7GB (just under 2.5 hours of standard-definition TV). A single-layer Blu-ray Disc can hold 25GB, which can be used to record over 2 hours of HDTV or more than 13 hours of standard-definition TV. There are also dual-layer versions of the disc which hold up to 50GB (a double-layer DVD stores 8.5GB). While standard DVD's use a red laser to read and write data, the new format uses a blue-violet laser instead, hence the name "Blu-ray". Since blue-violet laser light has a much shorter wavelength than red laser light (405nm, compared to 650nm), a blu-ray laser can read and write with much greater precision, hence the dramatically increased storage capacity on a disc of the same size.
Blu-ray was designed with this application in mind and supports direct recording of the MPEG-2 TS (Transport Stream) used by digital broadcasts, which makes it highly compatible with global standards for digital TV. This means that HDTV broadcasts can be recorded directly to the disc without any quality loss or extra processing. To handle the increased amount of data required for HD, Blu-ray employs a 36Mbps data transfer rate, which is more than enough to record and playback HDTV while maintaining the original picture quality. In addition, because random access is still our friend, you'll be able to playback video on a disc while simultaneously recording your favorite HD programs. And how awesome will it be to play video games from discs with this high a capacity and data transfer rate, to say nothing of how fast I'll be able to back up my favorite financial data files and Thai recipes.
The first commercial Blu-ray drive was launched by Sony at the end of 2004, priced at a non-trivial $2700. But I think we can chop a zero of that in the next couple years or so.
By the way, Sony officially announced last week that the Playstation 3 will leverage Blu-ray technology!
Check out more about Blu-ray at www.blu-ray.com.
HD-DVD
The HD-DVD format (also called AOD, for "Advanced Optical Disc") was formally launched in June, 2004 by the DVD Forum, an international association of hardware manufacturers, software firms and digital video content providers. HD-DVD was developed and primarily still backed by NEC and Toshiba. HD-DVD was actually on the drawing board prior to the release of the traditional DVD format, but real development didn't begin until 2003.
Like Blu-ray, HD-DVD's use blue-violet laser light to achieve higher storage capacity on the same sized disc. However, HD-DVD boasts a capacity of 15-30GB, compared to Blu-ray's capacity of 25-50GB. But, we all know how these things change and leap-frog each other over time. Also, where Blu-ray is specifically targeting the MPEG-2 codec, HD-DVD has three video codecs in mind as mandatory: MPEG-2, MPEG-4 AVC (H.264), and Microsoft's Windows Media 9 (VC-9). An upside, though, is that HD-DVD uses the same basic format as the traditional DVD's, and can therefore be manufactured with the same equipment, saving on development costs. This translates to a higher probability of an affordable unit hitting your entertainment center sooner. But, then again, good-ole' capitalism will probably force Blu-ray to hold its own on this front soon enough.
For more information on the DVD Forum and the HD-DVD format, see www.dvdforum.org.
Other Competitors
Blu-ray and HD-DVD are the two major competitors in the market, but others are out there. Warner Bros. Pictures has developed its own system, called HD-DVD-9. This system uses a higher compression rate to put more information (about two hours of high-definition video) on a standard DVD. Taiwan has created the Forward Versatile Disc (FVD), an upgraded version of today's DVDs that allows for more data storage capacity (5.4 GB on a single-sided disc and 9.8 GB on a double-sided disc). And China has introduced the Enhanced Video Disc (EVD), another high-definition video disc.
An Interesting Rumor
If you believe the rumor mill, it could be that the future holds a whole lot more in the way of single-disc data storage than a 50GB Blu-ray.. According to T3 magazine, Pioneer is developing an optical disc that could hold up to 500GB of data using ultraviolet technology - even farther down the tiny wavelength scale than the blue laser technology in Blu-ray equipment - around 70nm, compared to the 400nm for Blu-ray and 650nm for traditional DVD). Now we're talking!
Reference
For an interesting read on Blu-ray and other blue-laser technologies, check out a HowStuffWorks article on Blu-ray.
