All About DVD Part 3: Blue-Ray and HD-DVD
New storage formats: DVD-HD and Blue-Ray
On the first glance, DVDs have just finished becoming common and are the best option available. But developers do not agree, trying to invent new needs for poor users. This time HDTV (High Definition Television)is considered to be the new technology that no video lover can live without. Compared with common TV, HDVT has several times bigger screen resolution and is technically able to display much more fine details. Of course, all this is available on special HDTV-ready TV sets only. Another problem is concerned with storage of HDTV video, as even the DVD-18 standard with its largest capacity among DVD swill not be able to store several hours of HDTV quality video.
Fortunately, developers of DVD have mastered so-called "blue" laser, which wavelength is only 405nm. By using this laser it becomes possible to achieve much higher data density compared with DVD disks that use "red" laser with wavelength of 650nm. This new technology would allow to store up to 200 GB of data on a multi-layered disk.
Unfortunately, the new formats war has sparked even before the end of the development of actual devices, with the same old players on the field: Sony and Philips with Blue Ray standard and Toshiba, NEC and Sanyo with HD-DVD format.
HD-DVD
HD-DVD (High Definition DVD), as clearly visible from its name, is official heir to the DVD format, approved by DVD Forum. This format is 100% compatible with both CD and DVD, not only from home user perspective but also on manufacturing level. Manufacturing HD-DVD will not require huge investments in new equipment, and this was the reason why such big companies as Intel and Microsoft decided to support it. Microsoft, for example, promised full support of HD-DVD in its new Windows Vista that should be released next year.
One single layer of HD-DVD disk has the same thickness as DVD layer (0.6mm) and can contain up to15 GB of data. This means that HD-DVD won't have any troubles supporting dual-layered and double-sided disks, besides; Toshiba announced the development of triple-layer HD-DVD, where one side of the disk would contain 45GB. The theoretical capacity limit for HD-DVD is, therefore, 90GB.
Along with MPEG-2, compression technologies such as MPEG-4 and Video Codec 1 (VC1, format based on Windows Media 9) will be used. HD-DVD Video disk swill have more advanced capabilities for interactivity than DVD-Videodisks. For example, it would be possible to play several different video clips in picture-in-picture mode, and it also would be possible to connect more than one remote control to the HD-DVD player in order to play videogames together. Internet access will also be included in all HD-DVD devices, so it would be possible to follow web-links straight from disk menu or to download new soundtrack or subtitles from the net. And these are only few of new features.
Internet connectivity is also demanded by the new encryption for HD-DVD and Blue Ray disks - AACS (Advanced Access Content System). Each disk is validated with online database prior to playing. If the disk appears to be counterfeit, the playing device will be locked. It is not clear, however, what to do in countries where Internet is not available in every household. There is certain possibility, though, that Blue Ray and HD-DVD will become luxury, just as SACD and DVD-Audio before them. Alternatively, it could become common only in distant future, when Internet will be available even in African deserts.
Despite stricter copy protection, manufacturers most probably will not add regional codes to HD-DVD as it provides more troubles than benefits, and although movie production companies still insist on keeping regional protection, most of DVD-Forum officials are against it.
Recordable HD-DVD are named in the same way as DVD: HD-DVD-R (recordable) and HD-DVD-RW (rewritable).
Blue Ray Disc
Blue Ray Disc (BD) standard is promoted by Blue Ray Disc Association (BDA), an organization formed for this particular purpose. By throwing away the compatibility with CD and DVD it became possible to achieve much higher capacity than HD-DVD. One layer of BD can contain23.3GB, 25GB or 27GB of data. As the layer thickness is much lower than the one of DVD and is only 0.1 mm (compared to 0.6mm for HD-DVD), it is possible to manufacture multilayered disks with high number of layers. The theoretical capacity of Blue Ray disk is 200GB. Unfortunately, manufacturing of these disks will require purchase of brand new equipment.
Initially Blue Ray disks could only be used with cartridges (same as DVD-RAM) because of poor protection from physical damage, but now this issue seems to be solved and plastic cartridges are not needed anymore. Codecs used to store video in Blue Ray standard are the same as the ones used for HD-DVD (Mpeg-2, Mpeg-4 and VC1). This is not surprising as Blue Ray and HD-DVD were designed to store existing formats of video, while in case with DVD new codecs were developed specifically to cater for new type of disks.
Blue-Ray disks have more advanced menu compared to DVD-Video. The menu offers more functionality and is generally written in Java language. Blue Ray devices require Internet connection just as HD-DVD ones do, and Blue-Ray disk menu also supports integration with Internet. As it was said before, Internet will be also required for AACS protection. Apart from AACS, Blue Ray also implements two unique protection measures - ROM-Mark and BD+Rom-Mark. ROM-Mark is a special hidden label on the disk, similar to watermark in DVD-Audio. It can not be copied and disks couldn't be played without it. BD+ technology is designed to check whether or not Blue Ray player was hacked, and in case if it is true, it will download new firmware from Internet in order to fix in appropriate modifications.
Blue Ray disks naming is slightly different from usual. Read-only disks are called BD-ROM, recordable are called BD-R and rewritable are named BD-RE (Rewritable).
Future Perspectives
Only time will tell if one particular format will prevail or if there will be a complete mess with formats again. At the moment both alliances are trying to do something to attract customers and manufacturers. Blue Ray is leading at the moment. Due to the more advanced copy protection and higher capacity Blue Ray Association managed to attract most of film production companies. Another plus for Blue Ray lies in the fact that PlayStation 3 will use Blue Ray disks and therefore will be able to play Blue Ray Video disks too. Apple Computers is also going to include Blue Ray drives in its computer packages. Apart from all of this, Blue Ray devices appeared on the market much earlier than the competitors.
HD-DVD may attract users because of its back compatibility with previous formats. Besides, manufacturers will not have to spend much effort and money to make disks of this type. HD-DVD is also supported by some major studios, such as New Line Cinema, Paramount Pictures, Universal Studios ? Warner Bros (however some of them support both formats) and IT giants such as b>Intel and Microsoft.
Summary
Unfortunately, multi format drive that could support both Blue Ray and HD-DVD will be very expensive and difficult to manufacture due to large differences in technology behind new standards. However, several companies already have announced the development of such devices. If they succeed, we can hope that new formats will be widely accepted very soon. If not, there is a certain chance that HD-DVD and Blue Ray will share the destiny of DVD-Audio and SACD and only few chosen ones will use them. Besides, it is still not clear whether or not consumers actually need high definition image. And if you take into account that many people often transform DVD into smaller AVI files and use them for viewing at PC, it becomes possible to assume that HD-DVD and Blue Ray manufacturers will have a hard time promoting their formats. Video-on-Demand also does not add popularity to them.
So, which format will prevail still remains a mystery.
By : Artem Chlegov
Keyword : dvd,hd-dvd,HD-DVD-R,blue ray disc,blue ray,blu-ray,hdtv,high definition,high definition television
