HD DVD and Blu-ray: Where are we going?
There have been many press reports about the new blue laser formats and whether one will win what has become a format war.
HD DVD, developed by the DVD Forum and based on a proposal from NEC and Toshiba, looks likely to be launched first. Blu-ray, developed by the Blu-ray Group, led by Sony, will be later, but promises more.
Earlier this year, both Sony and Toshiba were reported to be making progress in unifying the two formats. This was what happened with DVD some ten years ago, when the two competing formats, SD and MMCD, were ‘merged’ to create DVD.
There was no format war then, at least not in the market place. It happened because the IT industry convinced the two sides that two formats were not in anyone’s interest.
But Toshiba very quickly announced that no agreement had been reached on a single format. They, then, announced a triple layer version of HD DVD, with a capacity of 45 GB, very close to the capacity of a dual layer Blu-ray disc (50 GB). Sony subsequently announced that Blu-ray capacity could be increased to 100 GB with a four layer version.
Very recently, we have seen an announcement that both Toshiba and Sony have given up hope of an agreement before the two formats are launched, but did not rule out such an agreement in the future.
Both formats have almost equal support from the major Hollywood studios, but Blu-ray has more support from consumer electronics and IT companies.
But why are there two formats not one, particularly after the experience with VHS, Betamax and V2000?
The two formats differ substantially in their physical construction, making any merged format difficult.
– HD DVD represents an evolutionary step from DVD. The discs have the same physical construction as DVDs but the pit sizes and track pitch are smaller to accommodate more data. Also, both HD DVD and DVD can contain HD (High Definition) video. In fact a DVD-9 can accommodate a full movie in HD video if one of the new video codecs, such as MPEG-4 or VC-1, is used. The result is that the discs are relatively easy to manufacture and there are no major problems in designing players and laser heads to read DVDs and CDs as well as HD DVDs.
– Blu-ray is a revolution in optical disc technology that is not compatible with DVD. Blu-ray discs have a cover layer which is only 0.1 mm thick instead of 0.6 mm for DVD and HD DVD. They are a departure from DVD intended to allow the maximum capacity, which is needed for MPEG-2 encoded video, such as used for broadcast HDTV in Japan and the USA. The result is a disc that requires entirely new equipment for manufacturing the discs, and presents significant problems for hardware manufacturers in designing players to read all formats.
But these differences are not enough to rule out Blu-ray because it is too difficult or HD DVD because it does not have as much capacity as Blu-ray.
This is why both formats have survived until now and both will be launched on an unsuspecting public, who may be the ultimate arbiters.
Few may decide to buy a format that may not last more than a few months. Content owners may be unwilling to release many titles on either format, particularly as the video specifications for each are also very different.
One possible solution is for multi-format players and recorders, as happened with DVD recorders and writers when faced with several recordable and re-writable formats. But this has not helped SACD or DVD-Audio which are both still trying to address a small market.
Graham Sharpless, previously with Deluxe and Disctronics, is now a director of Optical Disc Technology Ltd, which offers consultancy services on a wide range of topics to the optical disc industry. Visit www.opticaldisctech.com or email gsharpless@opticaldisctech.com for more information.
