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High Definition and the future of viewing

Disk and broadcast systems battle it out

Further background: The HD contenders

Consumer electronic manufacturers are currently touting two main HD optical disc formats. The first is Blu-ray Disc, now more commonly known as BD. The other is HD DVD (short for High Density DVD), an extension of the DVD format, also sometimes known as its previous name Advanced Optical Disk (AOD).

However, several other formats are seeking to stake a claim in the market, most notably the Chinesemade Enhanced Versatile Disc (EVD) format.

Blu-ray Disc (BD)

Announced in February 2002, BD undoubtedly has the biggest number of supporters in the consumer electronics and PC manufacturing fields. Its founding members were Sony, Matsushita (Panasonic), Philips, Pioneer, Samsung, Thomson, Sharp, Hitachi and LG. The format has since attracted the committed support of Dell, HP, TDK and JVC.

Notably, BD most recently obtained support of sorts from US studio Fox, which joined the BD Association. However, Fox has been at pains to make clear that its membership is motivated only by a desire to learn more about the format and influence it from the inside - rather than being an explicit commercial vote of confidence in the format. Indeed, Fox has also been positive about the attributes of the HD DVD format.

From the outset, the founding members felt that the BD format was a technical departure from the existing DVD standards, and therefore did not fall within the ambit of the DVD Forum. The technology is now being pushed by the recently founded BD Association (BDA), formerly known as the Blu-ray Disc Founders (BDF).

Though BD, like HD-DVD, uses a blue-violet laser rather than the conventional red laser found in today’s DVD players, the similarities effectively end there. The information layer itself gets as close to the disc surface as possible, with a 0.1mm cover layer to the disc, in an effort to generate the maximum amount of storage from a 12cm disc. This is in contrast to a cover layer thickness of 0.6mm for standard DVDs. (Nb: for CDs - the first generation optical disc - the information layer is at the back of the disc, so the cover layer is 1.2mm.)

The difference in technology has meant that BD is able to promise large storage capacity - 25 Gb on a single layer disc, 50 Gb on a dual layer. In the long term, the backers envisage the disc will be able to go up to four layers, offering over 100 Gb space per disc.

Translated into content, a 25 Gb disc with the appropriate MPEG2 encoding will be able to store 135 minutes of an HD feature, and two hours of standard definition extra features. A dual-layer 50 Gb disc can store a three-hour HD feature and two hours of bonus material in HD. For TV programmes, the large capacity can also mean that an entire series may be stored and sold on one disc - up to 22 hours of standard definition content on one 50 Gb disc.

A BD-ROM read-only physical disc specification (the format on which eventual pre-recorded content will be released) was finalised on 11 August 2004 and made available to disc manufacturers and other interested parties. In terms of compression and encoding, content can be encoded in MPEG-2, but the format backers have opted to additionally endorse both Microsoft’s VC-1, and the AVC flavour of MPEG-4 as mandatory advanced codecs to be supported in all hardware products, allowing content owners a wider choice to suit their requirements

The BD-ROM application layer has yet to be completely finalised. Although the specifications describing how linear video content should be stored on BD-ROM discs are bedded down, there are still some outstanding elements to the interactive features for the format that are being refined.

Some crucial issues regarding the implementation of an effective copy protection solution have yet to be finally resolved. This is a process that the BD format backers are currently working through with the major US studios. A copy protection system was developed by some companies within the Blu-ray group. More recently it appears that agreement has been reached - in common with the competing HD DVD format - to adopt the Advanced Access Content System (AACS) developed by a consortium of studios, consumer electronics firms (including BD backers Sony and Matsushita) and information technology vendors.

A recent breakthrough for BD was the major improvements made to strengthen the discs. In the early stages, the BD disc integrity was prone to damage and therefore had to be housed in a cartridge. However, TDK’s addition to the BDA brought new hard-coating technology that has meant the discs are tougher even than existing DVDs (uncoated - the coating technology is also applicable to them), and all BD formats are defined without cartridge.

The first BD recorder, Sony’s MPEG-2-based BDZ-S77, was launched into the Japanese market in 2003, costing $3,830. Mid 2004, Panasonic started shipping its BD recorder in Japan and LG started shipping a BD recorder on the Korean market. Most recently, in November 2004, Sharp announced the introduction in Japan of its BD recorder with integrated hard-disk drive and DVD player. Launched on 9 December, the BD-HD 100 model had a price tag of $3,000, with the ability to not only record onto the BD format, but to also store 19 hours of HD broadcasts on its 160 Gb hard drive. The model mimics the red laser hard disk/recordable DVD combination devices that have proved to be rather successful in the Japanese market.

Notably, the addition of a DVD player has meant that content from as many as six DVDs could be archived onto a single BD. However, shipping of BD-ROM consumer products is not expected to begin until late 2005 or early 2006, by when most of the BD backers will be bringing consumer machines and PC hardware to the market.

Importantly, Sony has already committed its next-generation PlayStation 3 games console to incorporating the Blu-ray format, as well as, it is expected, its Vaio PC notebooks. Moreover, the Japanese giant’s studio Columbia-TriStar has already pledged its support to the Blu-ray format, as is expected will the recently acquired MGM.


HD DVD, as its name suggests, has grown out of the existing DVD format supported by the DVD Forum. In August 2002, DVD founder Toshiba and consumer electronics firm NEC formalised a joint proposal to the Forum of a blue laser format based on DVD’s current construction of bonding two 0.6mm thick discs together.

Later joined by Sanyo, the premise of the format has been very much cost-focused. Literally billed as ‘next-generation DVD’, the backers contend that the physical similarity of the HD DVD format with today’s standard definition DVD means that the cost to disc manufacturers and replicators will be as low as permissible (an important point when considering that most manufacturers made their infrastructure investments only a few years ago). However, critics point out that it remains to be seen if older replication equipment can really be used to meet the stricter tolerances required by HD-DVD.

Given the reliance on a 0.6mm disc, the HD DVD format does not offer the same storage capacity as BD. A single layer HD DVD offers 15 Gb of storage, up to 30 Gb on a dual layer. On the 15 Gb disc, using MPEG-2 compression this translates into a 120-minute HD-quality movie with no space for extras. The 30 Gb disc can, however, store a 180- minute movie and just under an hour of standard definition extras. In effect, the dual layer HD DVD format provides a similar storage capacity to the BD single layer.

Like BD, HD DVD is in the process of finalising its various specifications. The DVD Forum approved an HD DVD-ROM spec in June 2004, with hardware support given to both MPEG-4 AVC and Microsoft’s VC-1 compression technologies as options for content providers to use. The advanced compression is arguably more important to HD DVD due to the lower storage capacity of the format. In terms of copy protection, it is likely that the backers of the HD DVD format will - as Blu-ray is expect to do - adopt the new AACS format, of which Toshiba is one of the developing founders.

Although Toshiba and Sanyo have demonstrated prototype devices, there is no HD DVD hardware on the market. Both companies have announced an intention to commercialise the hardware in late 2005, with Toshiba also integrating the HD DVD drives into its branded laptops.

At launch, Toshiba’s consumer HD DVD players are expected to retail for $999 in the US and around ¥10,000 ($925) in Japan. The company is hoping for 1,000 HD DVD-based movie titles in 2006, and as many as 10,000 titles in 2007 (though this is unlikely to be any more than speculation at this point). Though no studios had officially committed by November 2004, it has been rumoured that Warner Bros, Universal and Paramount are poised to pledge content to the format, whilst Fox has also given its support to HD DVD (but stopped short of committing any actual content).

NEC is expected to commercialise HD DVD drives in the PC and PC peripherals market in the same timeframe.

Next page: Other formats

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