A global shortage of high-speed DVD media is emerging, as consumers find it hard to get hold of media that matches the speed of their DVD authoring drive.

Memorex first shipped 4x DVD-R media in August, eight months after 4x DVD-R drives shipped. In the US there's scarce supply of 4x DVD-R and DVD+R media in stores. Likewise, 4x DVD+RW media is available only in limited quantities four months after the drives' release.

Short supplies of high-speed media are driven by two factors. Drives support faster write speeds even before the corresponding media specification is ratified and once the media specification is finalized manufacturers must submit their media for approval by the relevant group - the DVD Forum (DVD-R/RW) or DVD+RW Alliance. This process can take up to two months. Compatibility matters and media must support both the latest and previous generations of burning technology.

Once that hurdle is overcome, it takes time to ramp up media production. Rich D'Ambrise, Maxell's director of technology, said it can take another two months before a vendor can pump out media in volume.

Verbatim marketing manager, Tim Clatterbuck, said: "When you introduce a new media, it takes time to transition the technology. It's not a matter of just changing the line, switching the dye, and making everything as it was before. It's a complicated manufacturing process".

To support faster write speeds it is necessary to "make the media dye composition more sensitive or increase the laser power (on the drive)," Schlichting says.

Usually, media vendors make the dye more sensitive. Plextor's PX-708A dual-format drive is the first to offer 8x DVD+R and addresses the media lag with hardware changes in the drive to allow burns at 8x even with 4x DVD+R media, says Howard Wing, head of Plextor's marketing.

Although many vendors agree lack of media is a problem, no one considers it an impediment to the market's growth. IDC expects 17 million drives will be sold this year, compared to 5 million last year.