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This is an old revision of this page, as edited by Dsc~enwiki (talk | contribs) at 12:32, 14 October 2005 (→POV pushing: capita selecta of optical recording physics). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Thank you

Thank you for writing and contributing this article!

please send me full seminar report on this topic at tomsondevisyahoocom (please change to @, to ., etc. this is used as a measure to prevent spam email...)

Copy Protection

It would be nice to include a discussion on the copy protection, if any, that will be built into the standard.

See the Security section. --Wulf 09:29, 17 September 2005 (UTC)

Stand-alone recorders and games consoles

This section needs rewriting, is in the future tense when talking about 2004. Likely some progress updates needed, eg PS3. --Sgkay 11:59, 17 May 2005 (UTC)

What about a new size standard?

SMALLER discs please please somebody SMALLER discs. Remember, mini versions of formats are always very limited in available content. Nice try Sony but the "Universal" Media Disc is a joke.

• Um, not here in Japan, as they remain a profitable, if niche, product line. And besides, UMD discs are just small DVDs, just as the CD single size standard in Japan until a few years ago was just a small CD... Similarily Sony is sure to make identically sized small Blu-Ray discs, which would be more than adequate to hold a movie and could be used in more portable players, etc. Theoretically existing memory cards, very small, could contain massive amounts of data, even an entire movie, and be played in existing PSPs, digital media players, etc, and be sold as stand-alone media titles should the price to produce them drop.

I feel that as long as discs remain incredibly convenient and portable, as the standard CD is, the focus should be much more heavily placed on cost, reliability, capacity, and backwards compatibility. The last one is especially important, especially when looking at DVD play as a major factor in the game industry wars between the PS2, XBox, and Gamecube. The Gamecube's size never resulted in increased market share and only served to hinder its possibilities. I predict that as the next generation of consoles are released along with the release of Blu-Ray and HD-DVD players, the sides chosen by the gaming companies show the importance of incorporating certain formats. The fact that Nintendo will abandon its smaller disc format should show you that it is less attractive to the manufacturer as well as the consumer, and this can be seen as a microcosm for the digital media industry as a whole. Smoove K 01:12, 2 September 2005 (UTC)

Next generation?!

Wouldn't it be smarter to say something like "third generation" or something like it?

We don't even know if it will catch ;-)

Blu-Ray's format is obsolete

I would appreciate if the anonymous 130.233.16.105, who according to his user page specializes on 'crisp bread', would stop vandalizing my text regarding the obsoleteness of the Blu-Ray format. Sony and Philips finalized the DVR (now called Blu-ray) format in 1995-1996, which means it is 10 years old, and there is no other convclusion than that Blu-Ray's format, modulation code, error correction code, filing system etc, is obsolete. Dsc 06:22, 10 September 2005 (UTC)

I would appreciate it if you had any documents or papers from 1995-1996 proving the existence of the final format back then and showing its design considerations (what it's "optimized" for) and its relation to what is currently being pushed forward under the "Blu-ray" name. I also question your analysis about Sony and Philips' intentions and in what part they were motivated by DVD licensing income. FWIW, the earliest mentions I can find about "DVR-Blue" are from late 2000, which was still in design phase at that time.

I don't deny that design on the format wasn't started when DVD was finalized in 1996, but that alone doesn't make the format ten-year-old.

I also resent your comment about my field of expertise. I come across and fix a typo during random browsing and suddenly I'm specializing in crisp bread? Come on. 130.233.16.105 23:57, 11 September 2005 (UTC)

You are right: you also contributed to the Mickey Mouse article. By the way, there is a 1998 article by Philips/Sony employees on the DVR format (now BluRay), namely Optical disc system for digital video recording, T. Narahara, S. Kobayashi, M. Hattori, Y. Shimpuku, Sony Corp. (Japan); G. van den Enden, J. A. Kahlman, M. van Dijk, R. van Woudenberg, Philips Research Labs. (Netherlands) ODS Conference, July 1999 . Note the remark on the year 1995 that "the parity preserve principle was first introduced by us in: J. Kahlman and K.A.S. Immink: U.S. Patent 5,477,222 (1995), where the principle was applied in a (d=1, k=8) RLL code." Also patent applications by Philips/Sony employees can easily be found to be first filed in 1997, see for example J.A.H. Kahlman, K.A. Schouhamer Immink, G. van den Enden, T. Nakagawa, Y. Shimpuku, T. Narahara, and K. Nakamura, 'Device for encoding/decoding n-bit source words into m-bit channel word, and vice versa', US Patent 6,225,921, May 2001, first filed in Oct. 1997. And probably invented and tested in 1996. Dsc 06:23, 12 September 2005 (UTC)

Very well. I can accept the reasoning to the extent that the physical format was finalized by 1999 (definitely not 1995-1996 as it is currently in the article) except for the transition to blue laser (by which time it was called DVR-Blue, for example at ISOM 2000), and that it is based on modulation and error correcting codes invented in 1995 and 1996. I don't think that still lets you claim that the format is "obsolete" (and the "some consider" way of putting it is fairly unencyclopedic since that way you can "find" support for just about any opinion). Anyway, the actual Blu-ray physical format, as it first appeared in the market in early 2003, wasn't finalized in that form before 2001. And the innards are still not fully finalized, as we all know..

Additionally, you did not provide any information supporting your claim about it being designed specifically for use in DV camcorders as a replacement to magnetic media. The article you linked repeatedly mentions it being designed for digital video recording (where, unsurprisingly, the name DVR comes from too), that is, recording HDTV signals in homes on rewritable discs. The editing of DV is mentioned, but the way I remember it was that it would allow editing and re-recording of DV streams with a tabletop device, with the DV streams being initially recorded on a magnetic media as usual.

The history&background section still needs clarification as to exactly what parts of the format are old (modulation & ecc), removal of the claim that the entire format is that old, adjustment of the claim about its design considerations, and show its design path (dvr (9 GB rewritable disc with red laser) to dvr-blue (22 GB rewritable disc with blue laser) to blu-ray (25 or 50 GB ROM/R/RW disc)) clearer, and information about what parts specifically are a hindrance to mass replication (more than just the thinner cover layer?). 130.233.16.105 12:42, 12 September 2005 (UTC)

My dearest anonymous User:130.233.16.105, I just presented the requested literature and patents that clearly prove that Blu-Ray's physical layer was designed around 1995-96, just a few months after DVD's unification (Sept. 1995, after IBM's Lou Gerstner persuaded the electronics industry to accept EFMPlus). The 1995 DVR physical format, inclusive of 17PP channel code and 'picket' ECC code, address formats, wobble, headers, block structures, is exactly the same as that of Blu-Ray, and was never seriously modified. So I do not understand why you state that it was finalized in 1999 and updated in 2001. Please let me know what was finalized/changed in 2001? May be you can also explain why a physical layer technology designed around 1995 is not obsolete? Just think of Windows 95. No new insights since 1995? Higher efficiencies? May be User:130.233.16.105 also thinks that the 1979 CD format or 1985 CD-ROM format are not obsolete? Come on.

I have the impression that User:130.233.16.105 did not read the mentioned ODS2000 article. The authors of that article clearly state in the first sentence of Section 2 that their DVR format is intended for use in 'a' optical disc based digital video recorder . The authors fully explain the various design considerations, including address formats, wobble, headers, block structures etc, which were all designed in 1995-1996. They also explain which special measures had to be taken to construct a home recorder plus format requirements. I believe that someone with a normal skill in the art can understand that the designer of such a disk format has to trade various conflicting parameters, and when you opimize for home recording you cannot optimize for replication. Thus, I suggest that before User:130.233.16.105 vandalizes my texts again, that he/she studies the ODS article and tries to understand its implications, and tries to understand why it can be stated that Blu-Ray’s physical format is obsolete.

Therefore, I firmly conclude that, unless someone proves that Blu-Ray's physical format is not obsolete, i.e. no new insights/technologies were unveiled or added since 1995, the term 'obsoleteness' will be included again in the article. Dsc 15:30, 12 September 2005 (UTC)

I did read the article, thank you very much.

Labeling the system "obsolete" is POV (see the three points at - you're the first I've seen to make such conclusions about the format). While I don't dispute the facts (the origins of the physical format), Misplaced Pages is still not a vehicle for original research (that is, conclusions made by *you* unless there is wide support for such view in literature). Obsolete also implies that it already has a reasonable replacement in the market, which it doesn't. Of course better optical disc formats are introduced every year in research literature, but that doesn't make the current ones obsolete from the market's point of view. The articles about CD and DVD don't mention them being obsolete though they are based on even older technologies, so I guess you should go change them too.

I propose the following wording: "From a technological point of view, the physical format of Blu-ray can be considered outdated since it is based on modulation and error correction codes invented in 1995 and 1996". I don't completely agree with this though; I think it should just state the facts about the format's origin and leave the "outdated" or "obsolete" conclusion to the reader to make.

As for mass replication, I still question what in the physical format is an inherent hindrance to mass replication. Yes, there's the difference in the thickness of the cover layer, and the Durabis hard coating technology. I however can't see these as being inherently problematic for mass replication, merely as something that requires changes in production lines. If there's something else, please specify what.

With the word "finalization" I mean that there is a specification for the entire system (physical format *and* the data organization on the disc (that is: file systems, codecs, software)) available. Certainly there may have been working prototypes of the bare physical disc in 1999, but that alone does not a complete optical disc system make.

Lastly, I still do not see how you make the jump from the much-talked digital video recording (like a VHS, or a DVD recorder) to camcorders (video cameras). 130.233.16.105 18:50, 12 September 2005 (UTC)

Revert

I suggest we revert this article to the "Revision as of 01:58, September 10, 2005". Looking at the changes, the only things that have been changed, are the inclusion of some weasel terms, the deletion of a useful image, and the addition of off-topic POV info about the DVD war... If nobody objects, I will revert day after tomorrow. --Wulf 19:30, 14 September 2005 (UTC)

Okay, no objections, revert completed :) --Wulf 05:58, 16 September 2005 (UTC)

Wulf, you are very quick with your conclusions and reverts. The loss of the DVD battle by Sony et al., leading to a) a small part of the royalty income and b) small influence in the DVD Forum, is essential to understand the history of Blu-ray, and must be part of the article. BD design started immediately after the conclusion of DVD in 1995-96. Since the engineers started so early and the standard was fixed, there was no opportunity to add new ideas to the format, and BD is therefore old-fashioned just like Windows95. This is not a POV, but a basic fact that can be checked (see above). So I am sorry but I will revert your reverts again. Dsc 07:02, 16 September 2005 (UTC)

Okay, I can agree with the latest version :) --Wulf 18:42, 16 September 2005 (UTC)

Durabis makes what screwdriver resistant?

The article says that Durabis makes a BD resistant to a screwdriver attack, but the linked news article implies it the test was on a normal DVD. Of course, it's difficult to infer the meaning since they refer to BDs as next generation DVDs.

Alternatives

The second paragraph here seems heavily biased against Blu-ray to me. It seems to draw conclusions about what the outcome of HD DVD vs. Blu-ray Disc in the marketplace based upon marketing-speak from the HD DVD camp. Locke Cole 05:55, 11 October 2005 (UTC)

POV pushing

It's unfortunate that this article has attracted POV pushers, including some people who ought to know better (Dsc). Anything that smacks of opinion and isn't fully sourced should be deleted without hesitation. Mirror Vax 10:20, 11 October 2005 (UTC)

It is unfortunate that interesting, and with some effort tangible, sections of the article were removed by Mirror Vax. It is also unfortunate that some contributors to the article, such as Mirror Vax, apparently miss required physics background to understand the physics of optical recording as someone with that background could immediately understand that there are great difficulties in BD’s mass replication. I have just added a note regarding the reading of thin discs in the presence of dust, fingerprints, and other anomalies. If you wish, I can add the name of a good physics book. So please do not delete it this time by remarking it as a POV. Dsc 16:06, 13 October 2005 (UTC)

Obviously the hard coat is an acknowledgement that there are robustness concerns. Equally obvious is that these concerns have not prevented BD from attracting broad industry support. How BD compares with CD/DVD/HD-DVD in practice remains to be seen. Mirror Vax 18:39, 13 October 2005 (UTC)

As explained, the hard coating will not solve the problem related to servo tracking. Polishing of BDs will be hard work. This difficulty was not mentioned by the previous 'coating' contributor, who apparently copied a brochure of a coating salesman. I added a note regarding the replication of BDs plus a reference (in order to make it non-POV) to the first paper published by Sony/Philips scientists on DVR, later called BD. It seems that some contributors to this article are mainly concerned in the fact that a commercial product such as BD attracts broad industry support, and less concerned in physics. Hopefully my additional note will not be too difficult to understand, otherwise please let me know, and I will forward additional references. Do not expect glossy brochures. Dsc 19:50, 13 October 2005 (UTC)

It is well known that BD has more replication challenges than HD-DVD. Every article about the subject mentions it. The rest is opinion. The article you cited says that the design is highly approproate for a "third generation" optical format. For some reason you think that supports your opinion that BD's design is inappropriate as a replacement for DVD (hint: DVD would be the "second generation" optical format). Mirror Vax 20:25, 13 October 2005 (UTC)

Good. I just scanned the Blu-Ray article and the term 'replication', as you mentioned of great relevance in comparing various competitive formats, cannot be found except for my addition. Rather strange is it? An earlier contribution regarding replication was deleted for reasons of POV. To answer your question: I do not know whether BD is appropriate, but I am keen to see a fair and non-POV BD article, which is based on facts, but this seems to be difficult since some contributors do not have the required physics background. The moment they see a physics-based argument, it is deleted as 'POV' or 'NOR'. Dsc 21:29, 13 October 2005 (UTC)

I wouldn't even call it "replication challenges". Those stories are marketing/PR spin from the HD DVD camp to try and make Blu-ray Disc look like the costlier solution. Anyone with even a minor inkling of economics will be familiar with the term Economies of Scale. While the equipment needed to ramp up production of Blu-ray Disc may be more expensive, after production is started those costs will very nearly disappear as far as the end user (consumer) is concerned. With regard to the physics issue, you cite one article in particular over and over again. Sadly the link is worthless because you must be a member/subscriber to view the actual article (your link only shows a summary and the author names). In any event, that the error correction technology was developed back in 1995 says nothing of the overall technology used in Blu-Ray Disc. If you could back up your edits/claims with verifiable sources I wouldn't have a problem. Locke Cole 21:56, 13 October 2005 (UTC)

"I do not know whether BD is appropriate, but I am keen to see a fair and non-POV BD article, which is based on facts, but this seems to be difficult since some contributors do not have the required physics background." Actually, your contributions are mostly opinion, and are not very technical. For example:

Here Dsc deliberately lies about BD/HD-DVD capacity:

After reviewing the above, your statement that you are only interested in the facts is not credible. I would like to see an apology for past conduct before I give you the benefit of the doubt. Mirror Vax 22:36, 13 October 2005 (UTC)

The DVR article, which details the premises of Blu-Ray is available from the website, is in my view public domain, but one has to pay a small fee. So Locke Cole is stretching the concept of 'public domain publication'. Yes, I admit, a system, built on a physical layer, which was designed in 1996, can work properly. Also Windows 95 works properly, but the moment you see an newer alternative like Windows 2000 you prefer the newer version. In ten years time interesting ideas has come to fruition that could not be implemented in Blu-Ray as the format was frozen.

One can easily delete remarks regarding dust and fingerprints susceptibility of thin substrates in optical recording, but one cannot ignore the laws of physics. After a tedious search for a free or low-cost publication, preferably on the web, (otherwise some contributors like Locke Cole might complain it is not in the public domain) I found , where you can read about the severe difficulties associated with thin, 100 micron in BD, discs. For someone with a physics background this is obvious. Essentially it has to do with the size of the light spot on the substrate, where the light enters the substrate. The thinner the disc, the smaller the diameter of that spot. As a result, particles on a thin substrate will obscure a relatively larger portion of the spot than particles on a thicker disc. A particle with a diameter of around 100 micron will completely obscure the light of a BD disc, while in HD-DVD the same particle will only obscure 5% of the light spot area, causing a small, 5%, amplitude modulation of the read signal. So in the BD case we have a complete drop out, while in the HD-DVD case we can detect most of the read-out signal. Clearly, this will affect the read-out and servo tracking. One can improve the error correction to deal with longer burst errors, but the servo control will remain vulnerable as there is no way to solve that. Note that a special 'Durabis' coating can never mitigate these effects whatever the PR people may promise in their glossy brochures. That concludes my lecture for today. Dsc 12:32, 14 October 2005 (UTC)