For the uninitiated, Blu-ray and HD-DVD are the next generation of optical storage, though there do exist several competing formats as well. Blu-ray offers about 25 GB of storage on a single layer, but a Blu-ray Disc (BD) can and will host more than one layer-hence a typical dual-layer BD will be capable of holding up to 50 GB. HD-DVD offers about 15 GB on a single layer. Dual and triple-layer discs of this format have been manufactured.
Again, for those who came in late, there’s a format war of unprecedented proportions taking place. The Internet is abuzz with discussions, news, views, and speculation on which format-which camp, so to speak-will emerge the winner and become the standard, whether there will be a peaceable co-existence, and a host of other things. What follows is a W5H of sorts on Blu-ray and HD-DVD, followed by the much-asked question, “Which format will win?”
So What Are Blu-Ray And HD-DVD?
The Blu-ray standard was developed by a group of companies called the Blu-ray Disc Association (BDA). Blu-ray gets its name from the “blue-violet” laser used to write the data to disc. (Different laser wavelengths have different colours.) The blue-violet laser has a wavelength much shorter than that used to write conventional DVDs, which happens to be red. The shorter wavelength makes it possible to read and write smaller “pits,” meaning that data can be packed more densely.
Ones and zeroes are stored on optical media-CDs and DVDs included-in the form of bumps and pits. A bump is an area of the substrate (the material on which the data is written) where there is no pit, so the pit is what is taken into consideration when one talks about burning data onto optical media. It is definitely not as simple as “a pit is a one and a bump is a zero,” but one can think of it that way to simplify things.
HD-DVD, too, uses the shorter-wavelength blue-violet laser. The name “HD-DVD” itself stands for, of course, High-Density Digital Versatile Disc.
Both the Blu-ray and HD-DVD camps say they will initially be providing “hybrid discs,” with a high-definition disc on one side and a regular DVD on the other-so that consumers will be able to play movies on their DVD players for now, in a measure of future-proofing.
How Are BD And HD-DVD Different?
We need to explain three terms here-numerical aperture (NA), track pitch, and pit length.
The light-gathering capacity of a lens is indicated by its NA. It is dependent on the diameter of the lens as well as on the quality of the optics. The higher the NA-meaning the lens can gather more light-the better.
The track pitch (see figure Track Pitch And Pit Length) is the distance between the centres of two successive rounds of the spiral track on which the pits are burnt. The smaller the track pitch, the more the number of tracks on the disc, and hence the more the data that can be stored on the disc as a whole.
The pit length (again, see figure Track Pitch And Pit Length) is simply the size of the burnt pit.
Now, the NA and the wavelength define the size of the laser beam. A higher NA and a shorter wavelength means a laser beam with a smaller area of illumination, which allows for the focusing of the beam with higher precision-and therefore, the possibility of a reduction in the track pitch and pit length.
Where the technical specs are concerned, the main difference between Blu-ray and HD-DVD is in the disc structure itself. HD-DVD uses specifications similar to DVD: the base disc is 0.6 mm thick, and the protective layer is 0.6 mm thick. Blu-ray uses a 1.1 mm base disc, with a protective layer only 0.1 mm thick. This “small” difference means a lot: in Blu-ray, the recording layer is closer to the disc surface. This means the laser has to pass through less material to read from and write to. This in turn makes for a higher NA for the laser lens (see figure The Effect Of NA On Lens Focusing). A higher NA, as we said, means a lower track pitch and a smaller pit length. And the lower track pitch and smaller pit length mean more data can be packed onto a BD than an HD-DVD.
The Effect Of NA On Lens Focusing
At left is a laser lens focusing the laser onto a CD substrate. Note that the distance between the lens and the top of the CD is quite large. Next is the DVD case; the NA value is larger, and the beam is more sharply focused. Finally, in Blu-ray, the NA is even larger, the lens gets even closer to the disc surface, the amount of material the laser has to go through is the smallest, and the beam is the most tightly focused.
So why does HD-DVD use a thicker protective material, and how come a BD won’t get scratched easily?
HD-DVD went with the thicker protective layer so that, by virtue of its similarity to DVD, no hard coating was required; this also meant it was easier to make future drives backwards-compatible Indeed, backwards-compatibility with DVD is one of the things HD-DVD proponents frequently state. However, it might well turn out that Blu-ray drives will be forced to be backwards-compatible with DVD as well.
Early BDs were indeed susceptible to scratches, so much so that they had to be enclosed in plastic caddies. But in January of 2004, TDK introduced a proprietary clear polymer coating under the name ‘Durabis’. This made BDs even more scratch resistant than DVDs! Now, BDs with the coating can also withstand attack by a screwdriver. according to a release on CNET News.com: “Researchers at TDK have developed a tough coating that will make scratched DVDs a thing of the past. In a test conducted by CNET News.com, a DVD treated with TDK’s coating survived a determined attack with a screwdriver with no effect on playability.”
Layers And Speeds
A single Blu-ray layer holds 25 GB; a single HD-DVD layer holds 15 GB. But it’s not as simple as “Blu-ray is higher capacity than HD-DVD,” as you’ll find out.
In March of this year, at the Media Tech Expo 2005 in Las Vegas, the two camps demonstrated their current disc production capabilities. A standard two-layer HD-DVD-ROM is 30 GB. Toshiba showed off a three-layer HD-DVD-ROM, which is 45 GB; this was essentially their response to the criticism of HD-DVD’s lower capacity. Now a dual-layer Blu-ray disc is 50 GB, but with 45 GB possible with three layers, HD-DVD had narrowed the difference to a mere 5 GB.
The capacity game itself is indicative of what’s going on in the format war. For instance, in response to Toshiba, TDK, a member of the BDA, said it was working on a four-layer Blu-ray disc, which would have a capacity of 100 GB. And in June, it was reported that TDK had delivered on their promise-a prototype recordable Blu-ray disc with a capacity of 100 GB had been developed. It is, of course, the most advanced optical media developed to date.
What about speeds? Data transfer speeds, though not as important as capacity, are still an important factor in the adoption of any storage medium. Here, Blu-ray is ahead again by virtue of the specifications themselves-specifically, the NA and the wavelength. Blu-ray needs a lower disc rotation speed than HD-DVD to reach the same data transfer rates. 36 Mbps (1x) is the base speed for BDs, but BD-ROM movies will require a 54 Mbps data transfer rate-so the minimum speed the BDA is expecting to see in drives is 2x (72 Mbps).
Blu-ray also has the potential for much higher speeds. While the media itself limited recording speeds in the past, the only limiting factor for Blu-ray is the capacity of the hardware. The upper limit of today’s drives in terms of constant rotation speed is about 10,000 rpm. This speed would result in a 12x (400 Mbps) transfer rate for a BD, and “only” 9x for an HD-DVD.
It’s true that such high speeds are not required today, and HD-DVD proponents are likely to point out that 9x or 12x should make no difference to the end user-you. In reply, Blu-ray proponents would say that the 9x/12x difference showcase the superiority of their technology.
Where And When Can I Get Them?
We can provide a few indicators here: for the general consumer, 2006 seems to be the year. Players for Blu-ray and HD-DVD discs should arrive in stores in the US, Japan and many other countries sometime in 2006. BD-ROM pre-recorded media will probably be available by early 2006. Recorders should become available later in 2006 or in early 2007. It’s not clear how much of a delay there will be in terms of availability in India.
Pioneer might soon introduce a Blu-ray writer for PCs. Toshiba might soon introduce drives for reading HD-DVDs in laptops. Imation, a member of the BDA and a name familiar in India, is finalising the development of both HD-DVD and Blu-ray media, utilising a protective disc coating for both formats. During 2006, Imation plans to launch BD-RE (rewritable) and BDR (recordable) 25 GB (single-layer) and 50 GB (dual-layer) media. At around the same time, the company also plans to launch the HD DVD-R (recordable) and HD DVD-ReR (Re-recordable) 15 GB single-layer and 30 GB dual-layer HD-DVD formats.
Who’s On Whose Side?
There’s news every week or so about someone having joined one camp or the other. Here are some of the more important or interesting facts.
The first consumer Blu-ray device in the US is expected to be PlayStation 3. In October, Paramount became the first studio to lend its support to both sides-earlier, it was part of the HD-DVD camp. Closer home, Moser Baer, interestingly, is on the HD-DVD side.
Prominent companies on the BDA (Blu-ray Disc Association) include Sony, TDK, Dell, Hitachi, Apple, HP, Philips and Samsung. The list of consumer electronics companies on Blu-ray’s side is long-from Panasonic, Samsung, Sharp and Pioneer to LG Electronics and more. Video game maker Electronic Arts is with Blu-ray, as are the entertainment companies Twentieth Century Fox, Vivendi Universal, Walt Disney, and, of course, Sony Pictures.
HD-DVD is being promoted by, amongst others, NEC, Sanyo, and the Wintel duo-Microsoft and Intel. Toshiba leads the HD-DVD consortium. Entertainment companies backing HD-DVD are HBO, New Line Cinema, Universal Studios Home Entertainment and Warner Home Video.
Blu-ray boasts of higher capacities, and that’s enough to make one wonder, “Why HD-DVD?” It appears that Blu-ray has everything going for it, including a lot of support from hardware makers.
But HD-DVD has one key advantage for now: cost. In the case of Blu-ray, new facilities will be required in all areas-disc and player manufacture, and also movie-disc replication. Since the physical specifications of HD-DVD have a lot in common with DVD, most manufacturing plants currently making DVD players, discs and movies can also be used for HD-DVD.
Proponents of the two camps say different things, and sometimes quote obscure sources. We can’t be sure who’s accurate, but we know that Microsoft and Intel have joined the HD-DVD bandwagon, thus lending some weight to the HD-DVD camp. Here are some things that HD-DVDers (if we can call them that) are likely to say:
- “HD DVD has a proven 30 GB capacity, while currently, Blu-ray has only delivered 25 GB outside of the lab-this is half of what its proponents promised.”
- “Both formats said they would develop a standard that supports playing of both, DVDs as well as their next-generation standards, but so far, only HD-DVD has delivered.”
- “The capacity for volume production of HD DVD discs is already in place.”
And as to Microsoft and Intel backing HD-DVD, they cited the following requirements of “any successful next-generation optical format for high definition,” which HD-DVD can deliver right now.
- Managed Copy is a guaranteed feature in HD-DVD that enables consumers to make legitimate copies of their discs to a hard disc.
- Proven low-cost, high-volume manufacturing.
- HD DVD-ROM discs will offer dual-layer 30 GB discs at launch, compared with BD-ROM discs, which will be limited to (single-layer) 25 GB.
- The compatibility of HD-DVD with DVD facilitates development of slim drives for integration in notebooks.
- HD-DVD supports the iHD interactivity standard, that uses XML-and Vista uses XML. Blu-ray does not!
So Which Format Will “Win”?
We’re as unsure as anyone else out there! Here’s a disjointed set of facts that could possibly have a bearing on the issue.
First, a word about hybrid discs. We mentioned that both camps will initially offer hybrid discs that can be played on existing DVD players. That was a simplification: the truth is that Microsoft and others claim hybrid discs will be a reality with HD-DVD, but probably not so for Blu-ray.
In late September, Richard E Doherty, program manager in Microsoft’s media entertainment technology convergence group, stressed the matter of timing in delivering a solution. Saying that “HD-DVD has shown that hybrid discs will be a reality for consumers at launch,” he indicated there was “no roadmap for the development and availability of a BD hybrid disc”!
Some say Microsoft will eventually support Blu-ray due to its inherent capacity advantage-there might not be native support for Blu-ray in Vista, initially, but it will be there! Vista is, of course, something one must think about when talking about technological storage and entertainment issues these days.
Who will get to the market first with higher capacities? It’s not obvious that it will be Blu-ray. Remember, we spoke about Blu-ray being limited to 25 GB (single-layer) at launch, compared to HD-DVD that would be 30 GB (dual-layer) at launch.
Here’s an example of the kind of bickering that seems to be going on these days: two months ago, the above claim was refuted by Blu-ray, which said that BD-ROMs will be 50 GB at launch, although no launch date was mentioned. Doherty had this to say about the 50 GB launch: “The 50 GB claim for BD-ROM discs is unproven and will not be available for many years to come, based on discussions with major Japanese and US replicators. Replicators not only do not have test lines running, they cannot even pre-order the equipment to begin evaluating this disc. They cannot judge the cost of these discs, or even whether they can be manufactured at all. Major replicators can mass- manufacture 30 GB HD-DVD discs today…”
There are more computer manufacturers backing Blu-ray, again because of the storage capacity aspect. Blu-ray is ready to go with 50 GB, and the theoretical limit for a four-layer HD-DVD disc is only 60 GB. The present might be in favour of HD-DVD, but remember that a 100 GB BD has already been developed!
In terms of the security and anti-piracy features that will be offered by the two formats, Blu-ray has BD and ROM-Mark, which HD-DVD doesn’t offer (see box Enhanced Security In Blu-ray). That means in theory, Blu-ray discs will be tougher on pirates than HD-DVDs, which is good news for the studios.
News of hardware support for Blu-ray keeps coming in. Just last month, it was reported that Panasonic would soon begin sampling what it claims is “the first optical drive control chipset capable of writing to any recordable or re-writeable disc format”-except HD DVD. Not much of a surprise, since Panasonic’s parent company Matsushita is backing Blu-ray. The chipset specifications list format support, and amongst these are CD-ROM, CD-R/RW, DVD-ROM, DVD-RAM, DVD±R/RW, BD-ROM, and BD-R/RE. No HD-DVD here, definitely! Panasonic said mass production of the chipset would begin in January next year.
One could look to history and see that this is just another format war. Case in point: when VCRs were introduced, there were two competing formats. Sony was pushing Betamax, considered technologically superior; JVC and Matsushita were pushing VHS. Sony refused to license Betamax to OEMs, while JVC and Matsushita licensed VHS to whoever wanted it. VHS became the standard. Sony is now pushing the technologically superior Blu-ray…
Talking about Betamax, one of the reasons your old video cassettes are VHS and not Betamax is because pornographers took to VHS and not Betamax. Like it or not, much of entertainment technology has been driven by “The Other Hollywood.” The porn industry releases over 11,000 new titles on DVD every year, compared to about 400 by Hollywood. In which case, we don’t know anything right now about whether HD-DVD or Blu-ray will win-the fate of the format wars might lie in the hands of the pornographers.
It may not even be Blu-ray or HD-DVD at all: it may be EVD, China’s next-generation DVD format! EVD is a red-laser format, and promises capacities of 16 GB. So what’s so great about EVD? Not much, except that China wants it. That country produces 70 to 80 per cent of the world’s DVD players, and manufacturers pay a large amount in terms of licensing fees to the international owners of the intellectual property patents for DVD players. China is not happy.
According to the state-owned news agency Xinhua, China will put EVD on the market “before 2008.” Hollywood is behind much of the development that’s happening in the high-definition storage arena, but what about China’s thriving movie industry, and Bollywood as well-considering that China’s biggest potential export market is India? Things could change as 2008 comes by.
There is some weight behind the idea that it will be the consumers who will ultimately decide what format will rule. So if HD-DVD is initially cheaper, which it might well be, it could gain the advantage-and take over from there.
This opinion is, in fact, shared by a large number of people: that they would upgrade their DVD players when the alternative became cheap enough-so it makes sense to think that whichever format becomes “cheap enough” first will obviously be “the winner.”
It could even be something as silly as a name! Historically, consumers have been more likely to adopt a new product when it comes as a natural progression from what it is replacing. HD-DVD seems the natural progression of DVD, in terms of the name. “HD-DVD” sounds like something to do with DVD, and, admit it, “Blu-ray” sounds like the name of a dangerous fish!
In Conclusion
The blue-laser DVD format war has been on for some time now, and will be on for the foreseeable future. There are far too many aspects to it to have explored here, and we can only hope you’ve gained a foothold on what’s going on in this space. 2006 will be an exciting year in the unfolding of this drama, what with mass shipments of drives and studios and other companies switching loyalties.
On the other hand, some people are tired of the deluge of news coming in about HD-DVD/Blu-ray. It might be just as well that you sit back and wait for a 50 GB (should that be 45 GB?) drive to ship to a store near you-and then go upgrade!
| Enhanced Security In Blu-ray |
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Copy-protection schemes on blue-laser discs are more advanced. BD and ROM-Mark are specific to Blu-ray; the scheme called AACS will be used by both HD-DVD and Blu-ray.
BD is an encryption scheme that allows for dynamically changing encryption schemes. If the encryption scheme is hacked, as happened in the DeCSS, it can be updated and used on all new discs. Why is this required? Content-Scrambling System (CSS) is an unsuccessful encryption system used on some DVDs. When the contents of a DVD are encrypted, “keys” are required to unlock the content-more technically, “key sets” (because there is more than one key involved). These key sets are licensed to manufacturers, who incorporate them into DVD drives and movies. As a matter of fact, the CSS algorithm was reverse-engineered in 1999, and a program called DeCSS was released onto the Internet. And from then on, all DVDs became crackable! BD will avoid such a scenario.
ROM-Mark is a watermark that players need to see before the disc can be played. Only licensed parties will be able to produce the watermark, and when you copy a disc, the watermark, which is undetectable, will not be copied-so piracy is, in theory, defeated. In addition, if the watermark is detected by any means, the ROM-producing devices, into which the technology will be built, will not reproduce the content. |