The dual-layer DVD burners will appear on the market some time this year. Tony Gomez, Camcorder’s technical editor, asked us me why I didn’t get more excited about the hardware that will deliver 8.5GB single-side writing capabilities.

Maybe I was a little negligent

because the engineers at Philips, Pioneer and Matsushita have done a great job of proving the technology. But only a few firms (such as NEC, Toshiba and Matsushita) produce the laser diodes which are bought by the true burner manufacturers that are then bought by the PC manufacturers and branded product producers. After they are all done, you can buy the new burner, produce your great DVDs and send copies to friends & family…

Compared to the present DVD+/-R media you use the new dual-layer discs are a beautiful work of art and technology.

The media chemists and scientists deserve a tremendous amount of credit for developing the two dye layers and special UV adhesive that bond the two breath-thin resin layers. Moving those specifications onto the high-speed media production line demands a lot of quality production attention. During the early stages only the name brand media manufacturers will have the equipment and talent necessary so you don’t produce more coasters.

Dual Standards, Dual-Layer

Because neither side has yet to blink, there will still be two different versions of DVDR9 media (+/-). By the time you read this the DVD+R9 media spec will be a matter of record. The DVD-R9 specs will still be making their way through committee and DVD Forum approval.

One format won’t be better than the other (unless you ask someone deeply committed to one camp or the other). However, it is a lot easier for two companies to work on a common goal and have six others agree than have multiple camps reach agreement and then get the coliseum of interested parties to agree.

All Philips and MKM (Mitsubishi Kagaku Media)/Verbatim had to do is develop the hardware/media technologies, make certain it could be inexpensively and reliably produced and the +RW Alliance was off to the races. Most of the rest of the members don’t care which way the wind blows…as long as it blows.

On the other hand Pioneer, Toshiba and Matsushita/Panasonic (two of the three don’t play well together) had to hammer out their differences, go through a series of different working group studies and get the 200-plus members of the DVD Forum to agree.

Dictatorships just seem to reach consensus faster than democracies!

Despite the fact that there are differences (incompatibilities) between the two approaches there are some similarities.

Both have two thin substrates joined by specially designed UV bonding materials. When the laser is through writing to the first layer, it increases power slightly and begins writing to the second layer. When you are playing the dual-layer DVDR9 disc (+ or -) you’ll have to look hard to notice the switch over from one layer to the other.

The result is a full 8.5GB or four hours of DVD-quality (16 hours of VHS —quality) video. Some manufacturers may refer to the capacity of four hours of SP and 16 hours of EP so make certain you understand the playback quality you want before you begin writing your write-once discs.

The other big similarity is that the DVD specification requires that players and drives read dual-layer discs. If you encounter one that will read “standard” +/- discs but won’t read DVD+/-R9 media it means the manufacturer had a design flaw which they should correct at no charge.

DVD+R9

Cross-section of a dual-layer DVD+R disc

The big hurdle was to keep the new write-once discs compatible with existing player standards.

MKM was able to deliver compatibility by designing media that uses a thin layer silver-alloy as a reflector in the upper layer. This has produced reflectivity that complies with dual-layer DVD-ROM standards. In addition, the laser beam can pass through the first and reflective layers to write to the second layer. Viola! You can write and read to each layer.

Of course all of that is an over-simplification because they also had to develop unique dye materials and coating techniques, silver deposition and grooves that are stamped into the media to guide the write and read processes.

 

The DVD+R9 format book has already been completed and approved by the alliance. The organization also has more feature and performance plans they are working on that you’ll be seeing over the next few years (speed increases and rewritable DVD).

DVD-R9

Dual-layer, single-sided DVD-R9 disc

The —R or DVD Forum approach is similar for write-once DVD media. It also provides 8.5GB storage capacity.

The reflection film on the first layer is semi-transparent. The bonding agent is totally transparent (as in dual-layer DVD video discs). You simply fill up the first layer and the (write or read) laser automatically moves to the second layer without missing a beat.

The pits on both layers are 10 per cent longer than on your present DVD-R discs. Each layer is molded in one substrate and the substrates are joined with the optically transparent bonding layer.

Even thought you’ll be able to write your data a number of different ways depending upon the application you are using, the two layers are treated as a single volume.

That means you can expect to have to upgrade your software to take advantage of the new burners and media (this is true of both +/-). This is because for video applications the software will take what is called the opposite track path (OTP) approach (Figure 3). The first layer starts at the ID (inner) area of the disc and the second layer starts where the first layer ends. This produces the seamless video storage and playback you expect with your movies.

Your Next Move?

Are you quivering to buy one of the new DVDR9 burners? Camcorder’s technical editor can’t wait to get his hands on the new devices (burners will be available before the media) to test them for you. At the same time he’ll also be rushing to test the 8x and 12x “standard” DVD+/-R burners.

So you’re going to face a double dilemma. Are you going to ride the speed wagon or the capacity wagon because there will be differences for some time to come?

Ask yourself a few questions?

  • Will I be satisfied producing 20 minutes of great video? Or two hours of great video? Or four hours of great video?
  • Will I get people to sit still that long to watch it (any of the lengths)?
  • How much am I willing to pay to be the first in my neighborhood to own a dual-layer burner and how quickly will multiple sources of media be supplying economic media?
  • Do I want to use my burner for data backup? 4,700 or 8,000 full color pictures? 400,000-plus documents (eight four-drawer filing cabinets) or about 800,000 (nearly 16 four-drawer filing cabinets?

If you’re satisfied with 20 minutes of great video you probably use your burner to write VCDs. If you need a full two hours of video from the kids’ recital, from your vacation, your wedding or son’s/daughter’s birth you probably are very happy with DVD+/-R and will want to simply upgrade to higher speed burners.

If you want to sit (and have others sit) through four hours of video or put months of movies on a single disc, you’re a prime candidate for DVDR9 burners. Or perhaps you want to save all of your video footage and use the burner for backup and disaster recovery. Again take a close look at the new dual-layer solutions.

Just when you thought your decisions had been simplified with dual format burners/media, someone comes along and offers you dual-layer solutions. CD-R/RW; 1x, 2x, 4x, 8x DVD+/-R; 2x, 2.4x, 4x DVD+/-RW; dual-layer DVD+/-R…

Life will never be simple again!

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