Four years after its debut, DVD (digital versatile disk) looks like it can finally call itself a major format.

At the end of a year that saw DVD-ROM become the predominant optical disc format on new mid-market personal computers and the launch of rewritable DVD-RAM, vendors at last week's Comdex trade show at Las Vegas have been giving attendees a glimpse of what's next for the format as software retailers report increasing use of the system.

The DVD-Video version of the format was beginning to move into the US marketplace at the time of last year's Comdex and the adoption, earlier this year, of DVD-ROM drives in favour of CD-ROM drives by many mid-market PC makers has helped expand the video market.

The PC software market has been slower to pick up the format, largely because the 650MB of space offered by a CD-ROM is sufficient for many current applications. There are a few exceptions - several encyclopaedias make use of the 2.4GB of space on single-sided DVD-ROM disks and, mirroring the early days of the VHS videotape format, the system is proving popular among adult software and image vendors.

"DVD is definitely starting to take off," said Michael Esposito, owner of Gentlemen's Video of Chatsworth, California. Esposito was showing his wares at AdultDex, an adult entertainment show that runs parallel to Comdex here each year.

About 25 per cent of the movies Gentlemen's Video sells are on DVD, up from 10 per cent just several months ago, Esposito said. "I expect it to go 50-50 pretty soon," he added.

David Hanson, a sales manager at a Tower Records store in Las Vegas, also said DVD sales have grown quickly in the past year.

"It's like it used to be when Laser Disk came out. Once people get a player, they want everything, they go crazy," Hanson said.

"DVD players have done extremely well since they were launched," said Kevin Hause, manager of consumer research at International Data Corp. (IDC).

The market researcher forecasts 2000 could be a big year for DVD. Currently, just over 4 per cent of US households already have a DVD player, according to an IDC survey. "And almost one out of five households say they are going to buy a DVD player in the next 12 months," added Hause.

The March launch in Japan and late 2000 launch in the US of Sony Computer Entertainment's (SCEI's) PlayStation 2 console is also likely to help expand the market for DVD-Video. The device uses DVD-ROM as its main media and features the ability to play DVD-Video disks. Sony anticipates sales in Japan of more than 1 million units in PlayStation 2's first month of sales.

In the rewritable media market, DVD-RAM is beginning to find its place and Comdex is being used by several vendors to launch the next-generation version of the system.

Current DVD-RAM disks offer a storage capacity of either 2.6GB or 5.2GB on single- or double-sided media respectively, although the new generation of the system increases this level of capacity. By using two recording layers on each disk, a single-sided, dual-layer disk can accommodate 4.7GB, while a double-sided, dual-layer disk will hold 9.4GB.

Vendors hope to begin shipping drives and disks to support the format in the first half of 2000.

The Comdex show also saw several manufacturers show off systems based on the already launched one-time recording format DVD-R and samples of DVD-RW, a rewritable version of DVD more tailored to storing video than data. The summer of 2000 should see the latter format hit the market.

Hitachi went a step further than that at Comdex, showing off a prototype of a new DVD-RAM-based digital camcorder that records images onto a new 8-centimetre version of the format.

(James Niccolai and Terho Uimonen contributed to this report.)