The roll-out of DualDisc hybrid DVD/CD media later this year could yet be hampered by a German company that claims ownership of the technology if talks between the intellectual property firm and major music industry players break down.

Each DualDisc is double-sided disc with a CD on one side and a single-layer DVD or DVD Audio on the other. The DVD specification limits disc thickness to 1.5mm, which is possible to meet using a slightly thinner CD layer than is found on regular CDs and a single-layer DVD.

Enter Germany's DVD Plus International which says it owns a European patent that describes a product just like DualDisc, called DVD Plus. The company has already filed a patent application for the technology in the US, though as yet it has not been granted.

DVD Plus chief Dieter Dierks filed his patent in March 1999, though was only granted the patent in June this year. Interestingly, the inventor is listed as one Robert Siebel. Seidel has a number of US patents for optical media techniques to his name, all of which were assigned to WEA, Warner Music's distribution and manufacturing arm.

DVD Plus says it reached a deal in 2000 with WEA which allowed the Warner subsidiary to market the hybrid DVD/CDs provided it marked the resulting products with the DVD Plus logo. DualDisc.com is registered to Warner Music's Strategic Marketing division in the US.

WEA's manufacturing business was later sold to Canada-based disc maker Cinram International. Cinram is manufacturing DualDisc products and, according to a Reuters report, believes there's nothing to stop it doing so.

That may change if DVD Plus' US patent application comes through. Indeed, the company says its legal representatives have been engaged in a dialogue with the major music labels since February 2004 when it first heard about the trial marketing of DualDisc in the Seattle and Boston areas.

DualDisc was approved by the DVD Forum, the body which manages the DVD specification, in June. That will allow DualDisc providers to use the DVD logo. However, Philips, which maintains the CD specification, has apparently refused to allow the CD logo to be used on hybrid product, just as it has thus far forbidden many copy protected discs to use it.

That may matter less than the DVD qualification since the music industry hopes to use DualDisc to promote its DVD Audio offerings. DVD Audio discs and their equivalent CD versions will be merged into a single disc in a single case. While production costs would rise, the labels could make significant savings on inventory and distribution costs. It would also allow music labels to promote DVD Audio without forcing customers to lose some the playback flexibility they've come to expect from CD.

The idea is that punters will be able to, say, play higher quality DVD Audio content at home and use the same disc to play the same music in their car's CD player.

From The Register