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Just How Compatible Is Dual Layer DVDR?

Discussion in 'Blu-ray & DVD Players & Recorders' started by Rasczak, Jun 13, 2004.

  1. Rasczak

    Rasczak
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    This article from a visitor to the Computex in Taiwan may be of interest to some. Briefly looks at some upcoming 16x PC DVD burners and HD-DVD versus BluRay (from the Toshiba view):
    http://www.anandtech.com/showdoc.html?i=2078

    The most interesting thing in this article though (IMHO) is the lack of attention paid to dual layer DVDRs (of both flavours). I can't help but wonder if this is linked with the fact that these disks seem to lack the compatibility they were first claimed to have?

    Considering these disks are supposed to be as compatible as conventional DVD9s then why do numerous DVD drives being released now be incompatible with them? There have only been a small number of tests since the Nero Infotool was updated to detect DVD+R DL read/write support. But looking at the major reviews of non-DL burners and most seem unable of READING the disks let alone writing to them:

    For example, the Pioneer S706:
    http://www.cdrinfo.com/Sections/Articles/Specific.asp?ArticleHeadline=Pioneer+DVR-S706-J&Series=0

    ...or the Samsung SH-W08A:
    http://www.cdrinfo.com/Sections/Articles/Specific.asp?ArticleHeadline=Samsung+SH-W08A&Series=0

    ...or the NU DBW-521 Combo:
    http://www.cdrinfo.com/Sections/Articles/Specific.asp?ArticleHeadline=NU+Combo+DBW-521&Series=0

    Still early days of course so we'll have to wait and see but all these drives should be quite capable of reading normal dual layer disks. The potential lack of compatibility of DVD+R DL disks is further implied by the fact that LG had to release a firmware to enable their 408x series drives to read DVD+R DL disks - which hardly suggests they are as compatible as implied.

    From a PC perspective compatibility of these disks isn't a major issue: DVD-ROMS/-RW drives will be updated pretty quickly and a cheap upgrade will solve any problems of incompatibility. But for set-top users who use DVD players whose drives are based on existing technology then it has to be a bad thing. Let's hope compatibility is better than it currently seems to be.
     
  2. PhilipL

    PhilipL
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    Hi

    Easy to answer, the marketing department of the RW Alliance has been working faster than the R&D department. They said all the same things about +RW several years ago and it never reached the compatibility level it was originally doubted as being! They also lied about being able to upgrade 1st generation hardware to support +R.

    +R DL has been released way too early in an attempt to increase hardware sales, market share and usurp the official DVD recordable formats. However maybe the DVD Forum has the right idea with their DL recording, and that is to throughly test and perfect the format before rushing it to the market.

    Another indicator that +R DL isn't as good as is made out is that the hardware is no more expensive with DL recording, why? If something is a real break-through and involved R&D to perfect and will work as advertised then you pay a premium for that hardware and not just the media. The media is still to arrive in any great quantities. Maybe it never will as they have not started mass production yet of +R DL which will be an untried method of manufacturing these discs using a different method than the "engineering" samples we have at the minute. No one knows if the yields will be good enough to enable price reductions and reliable compatibility.

    The other major stumbling block to compatibility is these discs have different optical characteristics to normal Dual Layer discs. The laser on playback devices has to focus and track through the spiral grooves used for tracking when recording. Being two layers there are two spiral tracks it has to focus through, these interfere with each older scattering the laser, as well as a dye that also has non-reflective areas where it has been ‘burnt’ with data, and then the reflective layer for the 1st layer that is bonded on top of the dye with additional chemicals, again weakening the signal. A pressed normal dual-layer disc just sees the laser having to focus through a nice translucent reflective layer only and lands and bits that appear clear when focused through, as these are not burnt but are “ups and downs” in the clear polycarbonate). The make up of dual-layer recordable discs therefore are much harder to read even if burnt perfectly, of course they don’t tell you this do they.

    Regards

    Philip
     
  3. Rasczak

    Rasczak
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    As always. When I purchased the Philips DVDR1000 it was amid claims from Philips that DVD+RW was "90% compatible". And in 2000 Philips announced there would not be a DVD+R as DVD+RW was SO compatible. Of course it all turned out to be rubbish.

    Personally I'm not sure that it will have much of an impact on the market. In the PC (data) world most consumers find 4.7GB enough - it's only video where the capacity is limited. And as the production of DVD+R DL disks is likely to remain the preserve of a few of the major disk producers prices won't fall that quickly:
    http://www.cdrinfo.com/Sections/News/Details.asp?RelatedID=5664
    ...as can be seen from that article $7-10 per disk - compared to the going rate of $0.80 for a single layer DVD-R.

    I am very interested to see how compatible these disk do turn out to be - if some of the latest PC DVD drives are going to have trouble it doesn't bode well IMHO. Still time will tell.
     
  4. Minx

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    There were several companies showing DL media prototypes at Computex and for example Ritek is about to start volume production within a week or two (probably with the help of technology provided by Ricoh Japan).

    For being displayed as supported in Nero Infotool the firmware must specifically have been written to support the format. A drive can read formats even if they don't show up as supported in Nero Infotool. For example I have a Pioneer DVD-ROM that doesn't show support for DVD+R/RW but reads them perfect.
    I know though that the Pioneer DVR-A07 does not read DVD+R DL with the current firmware but the older Pioneer DVR-A05 and DVR-A06 read them perfect (even though support of course is not displayed in Nero Infotool). For the Pioneer DVR-A07 there will probably soon be a firmware update fixing support, at least when Pioneer releases a DVD+R DL drive.

    LG's DVD writers actually read DVD+R DL with DVD-ROM book type even with older firmwares and burning with DVD-ROM book type is more or less necessary to get a decent compatibility of DL discs.

    A German magazine performed a test showing that 21 out of 23 tested set top DVD players read the DVD+R DL disc with DVD-ROM book type without problems. Also 11 out of 13 set top DVD recorders read them. For PC drives the support was a bit worse but still it looks pretty good imho.

    Time will tell but I doubt it. DVD+R DL has not exactly been rushed to the market. I think it was in development for more than two years before the first official announcement. Anyway it will be very interesting to see how Pioneer will handle the disc category/book type issue though as allowing the use of DVD-ROM book type is most likely necessary if the compatibility should be decent.

    Hardware is not more expensive because there is a keen competition in the DVD writer market and no new hardware components are needed for DL writers. For example NEC (largest maker of DVD writers in world now I think) has released the ND-2510A DL writer which is electrically identical to the old ND-2500A. Still for example Sony tries to sell its DL writers at a premium price...

    Of course a burnt disc will never have exactly the same characteristics as a pressed disc but if they are close enough most drives will read them and that applies to both single layer and dual layer discs.
     
  5. Rasczak

    Rasczak
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    The key point was there was no high profile status of dual layer DVD+R. This is surprising because this is where the + camp currently have, on paper, a major advantage over the - camp. So why was it not exploited? Perhaps because of some underlying issue - possibly compatibility. Instead the show focused on 16x DVDR - which is all well and good but with 8x or 16x drives your only talking about a couple of minutes difference in burning - not really that significant.

    Volume production of DVD+R DL has already started. Interestingly it is in a similar position to DVD-RAM in that it is more compex to produce and thus will only be made (for the time being) by the major optical producers. Whilst this is bad from a price perspective (we can expect DVD+R DL disks to be upto 10 times the cost of single layer disks) it will perhaps be a good thing for quality of media (as thus longevity).

    LG's DVD writers DO have a problem with reading dual layer disks hence the updated firmware. There have been extensive discussions on this elsewhere.

    I should have been clearer when discussing the InfoTool. What I was saying is that despite being well aware of the existance of DVD+R DL (and having samples to test) all these drives are being shipped without any native support for dual layer DVD+R. This is a very bad thing IMHO.

    Can I ask which German magazine? I would be interested in seeing the results and what recorders they tested. I am passing through Austria next week so will be able to pick up a copy. Ultimately numerous 'tests' were done in the early days of DVD+RW which claimed it had the best compatibility. Extensive user tests have now shown this to be incorrect. Don't get me wrong - I hope DVD+R DL turns out to be at least as compatible as DVD+R (I would hope for more so to be honest) - but given the DVD Alliance's track record I will not hold my breath.

    Bottom line with dual layer DVDR (of both flavours) is a question of wait and see. Nobody will know for sure until extensive user tests have appeared online (for example until the DVDR Help database is updated with sufficient entries).

    BTW welcome to the forums Minx!
     
  6. Minx

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    C'T, issue no. 11. No. 13 is already out though so it might be hard to find.
    Thanks! :)
     
  7. Rasczak

    Rasczak
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    Cheers - will get a back issue and post the findings. There's no doubt that double capacity DVDRs are going to be useful (I already have a few recordings on my HDD that are just awaiting the arrival of DVDR DL before I burn them to DVD-R at an appropriate bitrate and author them on DL disc on a PC).
     

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