GOVT. TESTS PLANNED ON LIFE EXPECTANCY OF RECORDABLE DVDs

Preliminary research already has found that life expectancy of write-once DVD+Rs and DVD-Rs is shorter than many manufacturers claim and can “vary considerably” among brands of media even within same class and format, Oliver Slattery, technical staff member in NIST’s Data Preservation Research Lab told conference. He said another important preliminary finding is that phenomenon of “jitter” can have major implications for long-term life of a disc, particularly if jitter isn’t controlled. Slattery said NIST has found jitter on some cheaply made DVD-Rs, and DVD+Rs often fall out of spec the first time such discs are formatted.

Pioneer USA Senior Vp Andy Parsons, not an attendee at Gaithersburg conference, told us a well made blank DVD-R or DVD+R disc “should last a very long time.” He said Pioneer’s accelerated life tests showed that “well-made stuff should be able to last many decades, even approaching 100 years.” As for jitter, Parsons said that refers to deviation in timing of recorded mark lengths in blank disc’s recording layer. In other words, if beginning or end of given mark is not formed precisely enough, the transitions can physically lie in wrong place relative to where player expects them to be, he said: “This means the timing of the mark is off, and enough of these that are out of spec can cause the signal to become garbled upon playback because the player can’t decipher them,” Parsons said. “Jitter is an issue on recordable media because the associated thermal processes are a bit more difficult to control precisely than the photo resist mastering process used to make replicated discs. The dye formulation plays a big part in solving this challenge.

According to Parsons, if a disc is recorded with marginal jitter, “then any degradation that may occur later will likely cause that disc to fail sooner than one that is dead nuts on spec with jitter. NIST may also have been saying that bad jitter implies bad quality media due to the difficulty the writer had in controlling formation of marks on the recording layer. If it had trouble writing to it in the first place, it stands to reason that the disc may not last very long. So jitter by itself is not really a cause of short life expectancy, but it could be an indicator that trouble is imminent.”

NIST will do accelerated age tests on 6 “popular brands” of recordable DVD media, encompassing total of 600 discs, for their ability to stand up to severe heat and humidity conditions, Slattery said. Discs will be exposed to 500 hours of incubation time at 80?C and 80% relative humidity, Slattery said. He said NIST foresees total incubation time of 13,000 hours and hopes it can complete tests within one year.

Separate tests being run by NIST with help of Optical Storage Technology Assn. are designed to gauge compatibility of write-once and rewritable DVDs with current crop of DVD-ROM drives. Tests are in midst of first phase and are scheduled for completion by Sept., said Subatai Ahmad, vp, Yes Video. Bob Zollo, pres., Software Architects, said tests are being run on 14 models of DVD-ROM drives from 7 manufacturers and represent roughly 60% of ROM units shipped through 2002. Tests also involve 40 discs from 19 manufacturers. Zollo said preliminary results have found: (1) Newer DVD-ROM drives perform “considerably better” than older ones on compatibility scale. (2) There were few compatibility differences between DVD+RW and DVD-RW formats or between write-once and recordable versions of same format. In fact, biggest differences were between brands within same class of media.

Similar tests on compatibility between recordable DVD and set-top DVD-Video players were supervised by Ralph LaBarge, pres., Alpha DVD authoring house. As with DVD-ROM tests, LaBarge told conference that compatibility scores were higher on newer DVD players and that most significant differences were between brands rather than formats. He said findings suggested that “you get what you pay for” in blank media. While virtually all testing was done on rewritable DVD+RW and DVD-RW and write-once DVD+R and DVD-R formats, LaBarge said one surprising finding was that UDF-formatting 4.7-GB DVD-RAM discs consumed so significant an amount of data that material that fit on DVD+RW or DVD-RW couldn’t fit on DVD-RAM container. Responding to our question, LaBarge said he couldn’t specify “an exact number as to how many bytes are lost in formatting a DVD-RAM, but I think it’s at least 2.5% of the total disc capacity.

On phenomenon of “DVD Rot” that has permeated Internet chat rooms, Melodie Gee, vp-gen. mgr. of replicator Metatec, said most DVDs produced by reputable media manufacturers probably could be “guaranteed for life.” But more susceptible were DVDs produced by unscrupulous companies, she said. To cut corners, she said, some unprincipled replicators have resorted to using poor bonding adhesives or metal substrates that are “not as pure” as specs would dictate. As result, she said, substrates become oxidized when exposed to the elements, making for deterioration reminiscent of “laser rot” phenomenon that plagued early laserdiscs or CDs. Gee said other replicators have been known to use inferior or recycled polycarbonate for discs’ protective coating or to substitute acrylics, which are much too “brittle” for DVD applications. There’s also wide disparity in use of labeling inks, she said, noting that “shrinkage” requirements differ between CD and DVD.

Meanwhile, “H.264” compression that’s at root of high- definition DVD proposals such as Warner’s HD/DVD9 was described as “the new kid in town” by Pankaj Topiwala, CEO, FastVDO, who has worked for last 3 years within ITU and ISO to standardize next-generation video codec. Topiwala said MPEG-2 has been “the star crowning achievement of international video compression standards and has had tremendous impact” because DVD, which is MPEG-2, “has been a big, big hit.” But Topiwala said MPEG-2 “is now a decade old, and it’s time to move on.” Topiwala said that based on his ITU and ISO experience, MPEG-4 alone doesn’t pack enough “compression gain to deliver a big hit.” Given 20% improvement vs. MPEG-2, he said, “that’s not enough of a home run to change all the technology” infrastructure. “HD is here and it’s going to arrive in a big way,” Topiwala said: “In fact, I'm predicting it’s going to arrive in a big way much sooner than other people are predicting. Although the DVD is selling very well right now, 3 years from now, I think HD-DVD will begin to sell very well and from that point, it will begin to take over.”

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In separate development coincidental to DVD 2003 conference, DVD+R/RW licensor Philips Wed. announced disc verification and playability test program for blanks of that format. Program requires media manufacturers to submit blanks for standards- compliance testing every 3 months in order to continue using trademarked +R and +RW logo. Manufacturers in compliance will be listed on licensor’s Web site -- although they can be removed if discs are found to perform poorly in market after testing. Submission to testing is mandatory before products are released on market, Philips said.