Top 10 Questions About HD DVD and Blu-ray

1. I'm happy with DVD. Why should I care about high-definition discs?

While both HD DVD and Blu-ray Disc offer a number of improvements over DVD, the most obvious one is picture quality. DVD was a huge leap in both convenience and performance over VHS, but its 480i resolution is well below the 720p, 1080i, and 1080p images both high-def disc formats can produce. And a DVD-Video disc just doesn't have the capacity to hold a full-length movie in high-def.

Both Blu-ray and HD DVD use blue lasers, which have a much shorter wavelength than the red lasers used by DVD and CD players. (For more on the technology behind the two new formats, see "Inside Blu-ray & HD DVD.") The shorter wavelengths of these new lasers allow data to be packed more densely on the disc's surface, so the disc can remain the same size as a DVD while holding a lot more information. Even single-layer high-def discs can hold three to five times more MPEG-2 video content than a standard DVD. And you can get even more onto a Blu-ray disc or HD DVD by using either MPEG-4 AVC (aka H.264) or VC1 (based on Microsoft's Windows Video 9) encoding.

The new discs and players also feature things like high-rez multichannel sound, advanced interactive features, networking capability, and Internet connectivity.

2. What are the key differences between HD DVD & Blu-ray?

The most obvious difference is Blu-ray's greater capacity. A single-layer HD DVD can hold 15 gigabytes of data and a dual-layer HD DVD can hold 30 GB, but Blu-ray discs boast capacities of 25 GB and 50 GB, respectively. The HD DVD camp hopes to soon offer 45-GB discs, while Blu-ray is working on discs that can hold 100 GB or more.

But there are several differences beyond capacity. For example, HD DVD's interactive features are driven by software called iHD that was developed by Microsoft, Disney, and the DVD Forum, while Blu-ray uses a specialized version of Sun Microsystems' Java software called BD-Java. And although both formats employ the same copy-protection scheme, Blu-ray imposes two additional layers of protection called BD+ and ROM Mark.

3. Why are there two formats, instead of one, like with DVD?

That's a million-dollar question with a ten-cent answer: The primary backers of the formats couldn't agree on a compromise. Despite some early hope that common sense would prevail, as it did with DVD, unification talks between the two sides eventually broke down over an inability to agree on the disc's physical format. The Blu-ray camp was adamant that their disc's greater capacity was essential, while HD DVD's advocates argued that their format's similarity to DVD made it the easier, less expensive transition to high-def discs. When you add other issues into the equation, from potential licensing and royalty revenues to the egos of some of the executives involved, it's not really surprising that we're faced with a choice between two incompatible high-def formats.

4. So which companies are supporting which format?

The allegiances are shifting like sands in the desert, but here's where they stood at press time. HD DVD was backed by Toshiba, Sanyo, Microsoft, NEC, HBO, New Line, Paramount/DreamWorks, Universal, and Warner Bros. The laundry list of Blu-ray backers includes Sony, Panasonic, Philips, Samsung, Sharp, Pioneer, and LG, as well as Dell, HP, Apple, Electronic Arts, Sony Pictures/Columbia, 20th Century Fox, Universal, and Disney. But Warner Bros., Paramount, Universal, LG, and HP now plan to support both formats. (Even Blu-ray stalwart Disney is reportedly considering HD DVD releases.) Both LG and Samsung have said the uncertainty over how the formats will fare is leading them to develop players that can play both types of discs.

5. When can I buy a player and discs, and what will they cost?

Toshiba's $799 HD-XA1 and $499 HD-A1 are scheduled to debut April 18. An RCA player, which is essentially the $499 Toshiba player, is expected soon after that. Toshiba's Qosmio G30 laptop ($2,400, due by summer) will be the first notebook to include an HD DVD drive. While these early HD DVD players won't provide 1080p output, later models will.

The first Blu-ray player - Samsung's $1,000 BD-P1000 - is due May 23, to be followed in June by the Pioneer Elite BDP-HD1 ($1,800). You can preorder Sony's BDP-S1 player ($1,000, July) at and Best Buy, and Vaio PCs equipped with Blu-ray drives will be available mid-year. But it now looks like Sony's Blu-ray-equipped PlayStation 3, which was supposed to be out this spring, will launch in November instead. Panasonic and Philips both expect to have players available by late summer. Philips plans to offer its SPD700 recordable BD-R/RW computer drive in the second half of this year.

One issue could be the number of movies available when each format rolls out. Two weeks before the original March 28 launch date for the Toshiba HD DVD players, Warner Bros. said its titles might not be available for several weeks. (The HD DVD introduction was subsequently moved to April 18.) And while Paramount and Universal have announced HD DVDs, as we went to press neither studio had firm release dates or pricing. But HD DVDs are expected to be priced similarly to Blu-ray discs, which will be $35 to $40 for new releases and $25 to $30 for catalog titles. Sony, Paramount, and 20th Century Fox all plan to have titles ready for the Blu-ray's May 23 launch. (See the listing of releases.)