Building and Burning Dual-Layer DVD
Posted Apr 12, 2004

The growing pains of DVD recording in the late 1990s occurred in relative obscurity. For the most part, they were barely noticed outside the small vertical market where the technology was initially used: DVD authoring studios, who used DVD-R media as "check discs" to test their productions on in-house DVD players before premastering the contents to digital linear tape (DLT) and sending the tape off to the replicator.

For those authoring houses, the initial $17,000 price tags of DVD recorders and similarly high media costs were necessary evils, consistent with the rest of their setup and operational costs. There simply was no cheap way to get into DVD in those days.

But DVD-R presented another problem for the early adopters: capacity. Originally, and for some time after its debut, DVD-R media maxed out at 3.95GB, which was 17 percent less than the capacity of a single-sided, single-layer replicated DVD. DVD-RAM was unsuitable for disc-checking because it was incompatible with DVD players, and the Plus formats didn't exist yet. Capacity grew a little as DVD recording grew a lot. Before DVD recording achieved the visibility and popularity it enjoys today, all the DVD formats—DVD-RAM, DVD-R, DVD-RW, DVD+RW, and DVD+R (in roughly their order of appearance)—achieved the 4.7GB capacity of a single-layer, single-sided pressed DVD.

And that's where they've stayed, capacity-wise, as DVD recording has bashed its way into the mainstream. We all know how it got there: by getting cheaper, faster, and more reliable; by multiformat drives quieting the format war; by the grace of simpler authoring tools, faster computers, and the ascendance of DVD "backup" tools like 321 Studios' embattled DVD X Copy; and by playing a key role in the home/hobbyist urge to capture life on digital video.

But writable DVD hasn't gotten any "bigger," which means it hasn't really gotten any better at its original mission: to provide viable facsimiles of titles in progress. Even more today than when the format debuted, commercial DVD titles take advantage of the full capacity of replicated DVD, which allows for two layers and 8.5GB per side, well beyond the capacity of DVD±R. (Replicated DVD also can be double-sided, but you can simulate the playback of a double-sided, single-layer DVD title much easier than a single-sided, dual-layer title with 4.7GB DVD±R.) More than half the Hollywood DVDs in circulation are dual-layer DVD-9s, and most professionals building titles for replication do a significant chunk of their work for DVD-9. And in the recordable DVD world, there's simply no equivalent.

That's all changing. Attendees of NAB 2004 in Las Vegas will find media manufacturers like Verbatim and drive makers like Sony doubling down and gambling that professional DVD authors and, soon, their consumer counterparts will pay a modest premium to (nearly) double the capacity of their recording media. In the biggest writable DVD announcement since Pioneer unveiled the DVR-A03, the first sub-$1000, internal ATAPI DVD/CD recorder, NAB attendees will witness the debut of "double-layer" DVD+R, a new write-once disc format that will offer 8.5GB capacity on a disc that will play in "most" existing DVD players when written in the DVD-Video format.

Developed by Philips and Verbatim parent Mitsubishi, backed by the +RW Alliance, and dubbed DVD+R DL, the new format will require new recorders, as well as supporting authoring and recording software. Verbatim says they'll have media in "late Q2," with volume shipments to follow shortly thereafter. Sony will launch its 700 Series drive, supporting DVD+R DL (as well as single-layer DVD±R/RW and CD-R/RW), in the same time frame, with both media and drive priced somewhat higher than their single-layer counterparts [see sidebar, "Delivering DL: Drives and Media"].

But how quickly, and how much, will DVD+R DL actually impact the market? Who will adopt it, and how fast? What authoring tools will support it, and how will they change, from a user's perspective, when they do incorporate DL support? Will the DVD Forum follow with a dual-layer version of DVD-R? (Pioneer has presented a dual-layer DVD-R spec but it hasn't been finalized yet—see "Pioneering" sidebar.) And, given that DVD recording is a multi-tiered market, serving a range of demographics and applications, how many of those tiers, demographics, and applications will actually know or care when DVD+R DL hits? Finally, what will authors need to know about the ins and outs of dual-layer DVD authoring with the leading tools in the market to get into the dual-layer game?

Authoring DVD-9
Long before there was DVD+R DL, there was DVD-9, the popular single-sided, dual-layer replicated DVD format. (Much as DVD-5 is a rounded-up name for 4.7GB single-sided, single-layer DVD, DVD-9 stands for 8.5GB single-sided, dual-layer.) Not all Hollywood DVDs are DVD-9s, but for the most part, any DVD you see that includes a two-hour movie and even a modest assortment of extras is likely to be a DVD-9.

Every DVD has a finite number of bits. With two or more hours of high bit-rate video and 5.1 audio, those bits go pretty fast, and the 4.7GB of a single-layer, single-sided DVD-5 becomes insufficient.

Enter DVD-9, which offers 8.5GB of capacity on two layers. DVD-9 has other advantages, like its greater resistance to piracy (copying a 6-8GB DVD-9 to 4.7GB DVD±R obviously requires some compression and loss of quality, which may make the pirates' customers think twice about paying for it), at least with recordable media. It's somewhat more expensive to replicate, but by and large, DVD-9 has come very close to being the standard for commercial DVD publishing.

The two layers on a dual-layer DVD are a reflective layer called Layer 0 and a semi-reflective layer called Layer 1. Layer 0 is always written first, and generally, the data that doesn't fit on Layer 0 goes on Layer 1. All DVD players are equipped to read dual-layer (DVD-9) discs. The read laser refocuses when switching layers.

There are two ways to author a dual-layer disc: parallel track and opposite track. According to Ralph LaBarge in his definitive book, DVD Authoring & Production (CMP Books), each layer written with the parallel method is independent, which means the read laser must not only refocus, but possibly be repositioned when switching from Layer 0 to Layer 1 or vice versa. The transition can take anywhere from half a second to one second or more. "Parallel track DVD titles are generally used on DVD-ROM projects or on DVD-Video projects in which there are [multiple] distinct programs stored on the disc that do not need to be played back in a seamless fashion," LaBarge writes.

The read laser reads from the inner hub to the outer edge on both layers of a parallel-track disc, which may require significant repositioning upon layer change. Authoring is simpler on parallel-track discs—you specify the layer break and make sure your project will fit on the disc. Capacity for each layer, according to LaBarge, is just under 4.27 billion bytes; there are no other restrictions on how much or little data can be stored on each layer.

Opposite-track discs, by contrast, are designed for seamless transitions. A typical use of opposite-track authoring is for a title in which the primary content is a movie that's too long to fit on a single-layer DVD, and the layer change will happen at some point during the playback of the movie. Upon reaching the end of Layer 0, the laser will automatically refocus for a seamless layer change. The laser reads Layer 0 data from hub to edge, and Layer 1 data from edge to hub (hence "opposite"), which physically enables the "seamless" change—refocusing without repositioning. For this to work, it logically follows that there must be at least as much data on Layer 0 as on Layer 1, so the laser won't have to move closer to the outer edge of the disc to begin reading the content on Layer 1.

According to LaBarge, it's advisable, whenever possible, to place layer changes at inconspicuous points in the video, when the screen is dark or the audio silent, so viewers won't notice if the player pauses to refocus the laser. (Some older players with smaller read-ahead buffers will pause no matter what; my 1999-vintage Pioneer DV-414, which trumps cheap new players on media compatibility and playing high bit-rate video from recordable media, pauses noticeably on every layer change). LaBarge also recommends lowering the video bit rate just prior to the layer change to allow the data buffer to store more frames. This tip only applies to authors using variable bit rate encoding, a feature not available in popular consumer tools. But it certainly applied to anyone authoring DVD-9s for replication when DVD Authoring & Production was published—a high-end professional audience—and will apply to most early adopters of dual-layer writable DVD technology.

Dual-Layer DVD Authoring: Sonic and the High End
The availability of DVD+R DL media has the potential to change DVD authoring in two significant ways: First, it will allow pro DVD authors who were already doing DVD-9 titles to check-disc their projects on cheap, disposable recordable media in standard DVD players. With the matrix of players out there now and the widening reliability and compatibility gap between high- and low-end players, this is a huge advantage, and will be realized almost immediately.

The other potential change affects the broader authoring community. As mid-level, prosumer, and consumer authoring tools incorporate dual-layer capability and build in support for dual-layer drives and media, more and more authors can start thinking in terms of project sizes beyond 4.7GB, encoding large video filesets at higher bit-rates, and knowing that they can publish their dual-layer titles on the modest scale available via duplicators and duplication services. Several factors will determine the dual-layer take-up at these other levels of authoring: media and drive pricing, how the technology is marketed, how dual-layer authoring and recording are presented in DVD creation tools at those levels, and how easy they make it for the user to get their filesets onto disc in accordance with the DVD spec.

In Sonic Scenarist, the granddaddy of DVD authoring tools and the solution of choice in much of the high-end market, you create a layer break by specifying the first file in the DVD fileset that will be located on Layer 1 of the disc. In the program's Scenario Editor, you click the Sort Tracks button in the Tools Bar to display a sequential list of files to be included in the title's disc image file. You then select the file that contains the first scene for Layer 1 and click Set Layer Break. Scenarist then places a red arrow by the layer break scene. In the Sort Tracks window, Scenarist gives you a running tally (by MB and percentage of total capacity) of data in Layer 0 and Layer 1, as well as an accounting of the total size of the title at that point in the project and remaining capacity (out of 8.5GB for a dual-layer disc). You can also choose Parallel or Opposite track in this window. In Scenarist, you control very specifically the physical location of files on a disc, which means if you rearrange your files after setting a layer break, you may place them in spots where cells can't play seamlessly. Scenarist offers Seamless Layer Checks to address this issue.

All of which sounds pretty simple if you already know how to author in Scenarist, which is assuming a lot. Sonic suggests that very little will change in Scenarist, as far as creating dual-layer titles goes, when DL-capable drives become available as output devices. On the recording end, says Rolf Hartley, vice president and general manager of Sonic's professional products group, "the process will be identical to creating a single-layer disc. All you're doing is identifying the device you're writing to."

And the appeal will be pre-ordained and immediate for Sonic's Scenarist-level customers, Hartley says. "For the longest time, users of our pro products have asked us, ‘How do we reference dual-layer titles?' Until now, they've had to output to a single-layer disc, then stop, verify the menu structure, et cetera. Now they'll be able to do full dual-layer reference discs and one-offs."

At this writing, dual-layer output is not available in the various "abstraction-layer" products that Sonic offers to users who want to put a little (or more than a little) distance between themselves and the DVD spec—products like the "creative pro"-level DVD Producer and DVDit! and the ubiquitous entry-level MyDVD. According to Hartley, adding dual-layer support to the underlying code of one tool is as good as adding it to all of them. "Our AuthorScript core technology is being refined and updated all the time," says Hartley. "It's the same in Producer, DVDit!, and MyDVD."

Sonic will implement dual-layer much differently in those tools from how it's applied in Scenarist: "The software will find the most logical place in the largest movie clip for a layer break," Hartley says. "If that can't be determined, it goes back to the user and asks him to set it within a legal range." As for the authoring process in a tool like Producer, much will stay the same: select volume size when you start and get a bit budget indicator "for the size of project you're creating." Select the output device you want—DVD+R DL as you would single-layer DVD±R, or DLT.

Sonic indicated that dual-layer support would be available in more of their products by the time this article hit the stands, and DVD+R DL support in particular would be incorporated by downloadable patches when the drives become available. A dual layer-capable OEM version of MyDVD will be available as soon as there are recorders with which to bundle it, according to Sonic's Paul Lefebvre.

In late March Sonic announced that it had expanded its HyperMUX DVD formatting technology with algorithms designed to support DVD+R DL. With Sonic advanced technology group general manager Jim Taylor calling DVD+R DL "a major breakthrough in recordable media for DVD creation," Sonic said its new HyperMUX-DL engine would be integrated at all levels of its software line, including the ubiquitous consumer tool MyDVD. Key features of HyperMUX-DL include SmartBalance, which automatically adjusts the layer break points in a DL title to minimize lead-out time; and JumpSafe, which is designed to select the "ideal title set layout and layer break point with precisely filled error-correction blocks" to minimize pause, distortion, and stutter when MPEG stream playback is interrupted at the layer switch.

DL on the G5: DVD Studio Pro
Windows DVD authors will be able to take advantage of DVD+R DL regardless of what authoring tool they use, as soon as the first Sony drive ships with the DL-capable version of Nero [see sidebar, "Delivering DL: Drives and Media"]. But Mac users are more at the mercy of their OS provider, in that they may have to wait for Apple to integrate a DL-capable SuperDrive. And in keeping with their policy of keeping mum on future product releases and developments, Apple refused to speculate on when or how that might happen, saying only, "We will have to see how the final iterations of the new formats shake out."

That said, DVD Studio Pro product manager Brian Schmidt did provide some information about how dual-layer disc authoring is done in the abstraction-layer tool DVD Studio Pro 2. So far, as with Scenarist, this has obviously been achieved with DLT media as an intermediary step to replication, but it's not likely the process will change all that much with the new output media.

To begin a dual-layer project in DVD SP 2, according to Schmidt, "You specify the disc size as 8.54GB and the number of sides as ‘1.' " (This distinguishes between single- and double-sided discs, DVD-9 and DVD-10.) "Then you author the title. You can have DVD Studio Pro automatically set the layer break point, or you can set it yourself using a marker. This is helpful if you want to make sure the layer break occurs during a cut as opposed to the middle of, say, a car chase. You can also arrange the track order in the outline view of DVD Studio Pro to control the order in which they are written to disc."

Mid-Level Dual-Layer Authoring: How it's Done
Two leading products have entered the mid-level DVD authoring space in the last two years: Ulead DVD Workshop (now in version 2) and Adobe Encore. These tools are abstracted from the DVD spec, used not so much for Hollywood titles but for several types of commercial projects. They offer flexibility, versatility, and a level of design complexity not available in entry-level tools like MyDVD and MovieFactory.

Dual-layer makes a lot of sense at this level, where economical software encoders supersede the pricey hardware encoders used at the high-end. While these software encoding solutions—and the PCs that propel them—have improved markedly in recent years, they still tend to require higher bit rates than hardware encoders to achieve comparable video quality. Which means software-encoded projects may reach the 4.7GB threshold with 25-50 percent less content than hardware-encoded titles.

The newest product in the mid-level DVD authoring scene is Workshop 2, and it's probably a sign of the times, or at least an indication of things to come, that one of the key new features of the software in this second-generation version is dual-layer DVD authoring. At present, this feature is designed for use with DLT media and titles destined for replication, so the inclusion of dual-layer support may say more in the near-term about Ulead's ambitions for the product itself—to reach into the professional commercial realm—than their ambitions or expectations for DVD+R DL technology.

Dual-layer authoring in Workshop 2 is fairly straightforward, according to Ulead product marketing manager Travis White. Though the software supports both opposite and parallel track modes, setting a layer break can be single-click simple. "In the Ulead DLT Writer dialog box," White says, "there is a check box, ‘Align split point to cell boundary or chapter point,' which users can check to allow Workshop 2 to align the split point to the best position. Or they can uncheck this option and input the split point themselves. For the split point," he continues, "we follow three rules: One, the size of the first layer should be equal to, or greater than the size of the second layer. Two, to make sure we have seamless playback, the split point should be on the cell boundary, otherwise known as a chapter point. Three, the split point should also be aligned on an ECC block (one ECC block is equal to 16-disc block of 2048 bytes each).

Once the user checks 'Align split point,' Workshop 2 will find the best position according to those three rules. The worst case is that no suitable point can be found to fit rule two; however, it does not violate the DVD specification. But in some cheaper DVD players, you will see some delay in the layer switch." Users also can set that split point themselves, he says, but if their split point makes Layer 1 bigger than Layer 0, they'll receive an error message.

In Adobe's Encore DVD, dual-layer output is keyed to DLT, which means a separate DLT for each layer, with each side containing a continuous image. As for authoring, according to Encore product manager Giles Baker, "Menus and timelines are laid out on a disc in a specific order according to their content and other considerations. So the layout of a disc is fairly fixed. Encore's task is to find a spot in that layout that allows it to be split across two layers of the disc. Ideally, that break will be indiscernible."

Encore, which writes opposite track only, chooses a place for a layer break without user intervention unless no appropriate spot is found according to its preset strategies. "Encore looks at the total size of the project to determine the range within the overall single image that the split can occur. As the total project size approaches the capacity limit of 8.54GB, this range shrinks," he says. "Then it checks to see if there is a non-seamless transition within that range. If there is, the break is placed there. If there's no appropriate place to put the layer break, Encore asks the user to choose a chapter point that falls within the allowable range. In some rare cases it may not be possible to place the layer break because there are no chapters. Encore will tell the user where the layer break should be placed and instruct the user to place a chapter point there."

Baker offers two scenarios to illustrate the above conditions. First is a project with two timelines (a term imported from Encore suite-mate Premiere Pro), with 4GB of content in each. Encore can place a layer break between the timelines without requiring user intervention. Second is a single-timeline project with a near-capacity 8GB of content. In this case, Encore will ask the user to select a chapter within a small range as an appropriate place for a split.

Where it's Going?
Dual-layer DVD authoring support is currently restrictive in several senses: output media is DLT-only, and companies, like Sonic, Pinnacle Systems, and Ulead, with multiple DVD products offer dual-layer output in only one or two at the high-end. But that's clearly changing with the onset of dual-layer drives and media. For example, Pinnacle Systems offers several tools with DVD output, among them the popular non-linear editors Edition and Studio, but currently only the DVD-specific Impression DVD-Pro supports dual-layer.

According to Pinnacle director of product marketing, William Chien, however, "We expect that dual-layer burners will replace single-layer burners at all levels of the market beginning in the second half of 2004. Pinnacle plans to support dual-layer burning in future versions of Liquid Edition, Studio, and the Instant CD/DVD products."

As for the impact of that capability in the consumer tools, Chien says, "We do not expect dual-layer support to add significant complexity to the GUI. Especially for the consumer products, this process will be automated. The only user interaction will be to handle the case when a user tries to burn a dual-layer project onto single-layer media."

Ulead's White agrees that dual-layer will ultimately reach the consumer authoring ranks, including Ulead's own consumer authoring tool, DVD MovieFactory. "As new burners settle out to more reasonable prices, we don't want to hold back from our consumer customers a great media benefit that is no more complicated to use. So we will make sure to put all new burning functions in all levels of Ulead product without complicating the interface."

At the far consumer end of the spectrum, DVD backup tool vendor 321 Studios plans to support dual-layer in their embattled DVD X Copy software as well. "As for dual-layer DVDs," says 321's Julia Bishop-Cross, director of public relations, "our software will support it, and it will only be a minor change to the current coding. Our software will attempt to duplicate the exact layer break, but may have to adjust slightly in some cases. Once the burners come out and we can get started with testing, it shouldn't be more than a few weeks before new versions of our software are able to support the dual-layer DVDs."

But White believes the first impact we'll see is in the professional market. "We see dual-layer support as essential for a pro authoring tool," White says. "Dual-layer burners are coming down the pike, so small-volume duplication is imminent. For users who don't have the multi-thousand-dollar encoder solutions, higher bit rates are desired to maintain pristine quality. Even though Hollywood DVDs float around 3000Kbps, the more affordable encoders can't maintain high quality at that bit-rate level for most content. So more disc space is very desirable. Many corporate and business productions can go well over an hour of content, especially if they are training and education-related. And that is a big part of our customer-base."

Adobe's Baker sees dual-layer recording affecting the market for Encore and for DVD authoring in general in several ways. "The availability of dual-layer burners will expand the opportunities for Adobe Encore users to create more diverse DVD titles with higher-quality video and audio," he says, because the higher capacity means both more content and higher bit rates. "It's likely that the Encore user base will expand slightly as a result of their availability. Some potential customers may be holding off on DVD production because they require larger capacity but not the large production runs."

As for how Adobe's customers will apply the technology, he says, "Users of Encore are likely to use dual-layer burners for desktop production of DVDs because they can offer services to their clients that previously required replication. That is a big step forward." Baker expects recording to DVD+R DL and dual-layer DVD-R media to affect the authoring-to-replication process in another more direct—though not immediate—way. "On the replication side," he says, "dual-layer recordables will probably start being used as masters in place of DLT, just as single-layer DVD-R has. This will depend on replicators developing a process to get the data and the layer-break information from the recordable media. So it's likely that there will be some delay before replicators are happy to accept this form of master."

White sees drive and media pricing as the key to dual-layer implementation at all levels of the market. "Once the dual-layer recorders and media are cheap enough, I think it will be much easier to duplicate commercial discs, and to make more high-quality DVDs for fun, education, sharing, business demos, and TV program recording," he says. "I think those dual-layer burners will easily go the way of every other burner, dropping to $299 or $199 in short order. At that point, any level of user will have a need for the new dual-layer media."

Delivering DL: Drives and Media
When the first dual-layer drives and DL media debut at NAB, they'll do so amidst lots of "future format" talk that may steal much of their thunder. Blu-Ray and the competing HD-DVD will be everywhere; hi-def video itself will command quite a bit of attention, particularly in the HDV-MPEG-2 video format and the new Microsoft/Sonic WMV-DVD initiative. But as far as the DVD here-and-now is concerned, the new era upon us at NAB will be the dual-layer era. Just as CD-R enjoyed its heyday in the early years of DVD, so will dual-layer DVD recording amid the anticipation and even the wee-hours dawn of Blu-Ray or its hi def-capable, high-density equivalent.

At this writing, it appears that DVD+R DL will be represented by two products at NAB: the Verbatim DVD+R DL media first displayed at CES in January, and Sony's 700 series Dual RW burners, which will add 2.4X dual-layer recording to the Dual RW repertoire of 8X (single-layer) DVD±RW, 4X DVD±RW, 40X CD-R, and 24X CD-RW. The first unit will be the DRU-700A, an internal ATAPI model; the DRX-700UL, an external USB 2/i.LINK (FireWire) unit will follow shortly thereafter. The external drives will boast a sleek new vertical look.

It's worth noting that the drives and media are +R-only at this point. The DVD Forum is working on a dual-layer spec for DVD-R, but it has yet to be finalized (see sidebar, "Pioneering Dual Layer DVD-R"). To distinguish the +R format from the forthcoming -R format, and add more terminological detritrus to the altready-cluttered world of DVD recording, the +RW Alliance insists that the "DL" in "DVD+R DL" stands for "double-layer." This not only differs from what they expect the Forum to call their DVD-R spec, but also what dual-layer DVD-9 has been called from the get-go. In any event, DeMoulin says, "When the Forum offers up their spec, we'll have a -R version."

The Sony drives will ship with a full software bundle of Nero tools, including versions of Nero Burning ROM, Express, and Vision Express capable of writing ROM and DVD-Video images to DVD+R DL media. As for how Nero got the nod for the 700 Series bundle, DeMoulin says, "They were the first to make the dual-layer stuff work. It helps that their location is very close to Philips."

According to DeMoulin, "The science of dual-layer is pretty straightforward." In a recent white paper, "Understanding Dual Layer DVD Recording," he writes, "Single layer DVDs have a wobbled pre-groove molded into the polycarbonate base that controls the rotation speed of the disc and provides the addressing scheme for the disc. In a dual layer recordable disc, each recording layer has its own wobbled pre-groove that controls rotation speed and addressing for that layer. However, the entire `table of contents' and system area of a dual layer recordable disc is contained only on the first recorable layer (Layer 0)." DeMoulin adds that data recorded to the discs will be written hub-to-edge on Layer 0 and edge-to-hub on Layer 1, which suggests opposite track-only from an authoring standpoint.

DeMoulin goes on to say that dual-layer discs can be written as DVD-Video and DVD-ROM, and even recorded multisession or packet. However the disc is written, its "two layers represent one contiguous address stream."

Though the drives will be demo'd at NAB in April, Sony has hedged the ship date as "Q2," which will mean May or June. Verbatim expects media to begin shipping in "late Q2" as well. As for quantity shipments, according to Verbatim representative Andy Marken, "There will be an allocation issue for at least a quarter."

Sidebar: Pioneering Dual-Layer DVD-R
While the DVD+R camp will clearly reach the market first with its "double-layer" media and drives, there's lots of activity on the -R side that suggests dual-layer DVD-R won't be far behind. Pioneer, the prime mover of all things DVD-R, announced on October 3 of last year that it had an 8.5GB dual-layer recordable DVD specification in the works, and demo'd its dual-layer technology at CES. In a white paper on the subject, also released in October, Pioneer published a point-by-point comparison of the physical characteristics of dual-layer DVD-R and dual-layer pressed DVD, indicating perfect matches in capacity, track pitch, channel bit length, reflectivity, and reference scanning velocity. The white paper also discussed the physical structure of the disc and its "soft stamper"-based manufacturing process, and announced plans to propose the disc to the DVD Forum and expectations for its commercialization.

So as of mid-March 2004, with NAB fast approaching, where does dual-layer DVD-R stand? "As we've learned in the past, it's hard to pin down an exact date," says Pioneer senior VP for advanced product development Andy Parsons. "We have presented our dual-layer spec technology to the DVD Forum, and hope a spec will be ready sometime in the second half of this year. We are motivated to get the spec ratified as quickly as possible, as there is clearly strong interest in the technology."

The 8.5GB version of DVD-R will be known as "dual-layer" (rather than "double-layer"), says Parsons, because the former "complies with the established terminology used for replicated DVD media. DVD-9s are typically called ‘dual layer,' and DVD-10s are usually called ‘double-sided.' Calling any other format ‘double layer' may result in market confusion—something we definitely don't need more of in the writable DVD space."

Much as Sony has reported on the DVD+R side, Parsons says there won't be a significant premium on the pricing of dual-layer DVD-R drives—the first of which will be the A09—although in the absence of a finalized and accepted spec he isn't ready to commit to anything more specific. "The cost impact on the drive design is relatively minor," according to Parsons. "I don't expect a big price impact." As to the question of whether dual-layer drives will replace single-layer DVD-R drives in the market, he says, "Since dual-layer models will be a superset of existing drives, I think it's safe to assume that future models will support both media types [single-layer and dual-layer DVD-R] from that point forward." No word yet on whether the dual-layer DVD-R drives will support DVD+R DL.

Parsons expects the initial take-up of dual-layer DVD-R drives to happen in the pro authoring sector. "Dual-layer DVD-R has been requested by professional authoring users from the very beginning—even when we were shipping the very first DVD-R drive in 1998 (a bargain at only $16,995!). So it's reasonable to expect that most users in the pro space will use it for running one-offs of their own DVD-9 content. This will be a liberating experience."

As for that experience effectively imitating the DVD-9 experience—that is, a check-disc, mastering source, or any dual-layer DVD-R, for that matter, providing the logical, physical, and playback equivalent of a replicated DVD-9—it largely comes down to effective handling of the layer-break. According to Parsons, this should not be a problem "when we know in advanced when the layer break is going to occur. Doing a layer break on the fly, say while recording live video, could result in a minor disruption similar to what we see during playback of long movies on replicated discs."

Not So Fast…
There is a lesser known problem that will affect both dual-layer DVD-R and DVD+R DL in their efforts to mimic replicated DVD-9. "All replicated dual-layer media are supposed to have both layers equally ‘recorded,' as this is what players expect to see optically," Parsons says. "So to make dual-layer appear as similar to replicated media as possible in players, we're thinking that discs may also need to be equally recorded across both layers before playback is attempted. This isn't an issue if you use the majority of the available data space on both layers, but we know from experience this won't always happen.

"If you saw our recording demonstration at CES, you may have noticed that we were alternating back and forth between layers on a parallel track path (PTP) disc so we could avoid having to fill up the second layer with dummy data. With opposite track path (OTP) media, it's possible that longer finalization times could be needed. Again, things like this are what make dual-layer media so different from single-layer, so we need to understand how most people (and products) will want to use them. Another question is whether we should offer both PTP and OTP discs—imagine that scenario at a retail store."

Companies Mentioned in this Article
321 Studios, Inc. www.321studios.com
Adobe Systems, Inc. www.adobe.com
Apple Computer, Inc. www.apple.com
Pinnacle Systems, Inc. www.pinnaclesys.com
Pioneer Electronics (USA), Inc. www.pioneerelectronics.com
Sonic Solutions www.sonic.com
Sony Corporation www.sony.com
Ulead Systems, Inc. www.ulead.com
Verbatim Corporation www.verbatim.com