The patent, No 4,698,672 (the ‘672 patent), is owned by Compression Labs Inc (CLI), which applied for it in 1986, but never pursued royalties. Scheduling software firm Forgent Networks subsequently acquired Compression Labs and startled the computer industry in 2002 when it announced that it would be seeking royalties relating to the JPEG patent.
JPEG is short for the "Joint Photographic Experts Group," which comprises experts nominated by national standards bodies and major companies to work to produce standards for continuous tone image coding.
The best-known standard from JPEG is IS 10918-1, which is the first of a multi-part set of standards for still image compression. A basic version of the many features of this standard is what most people think of as JPEG – and this is where Forgent is claiming a monopoly right.
The company has so far licensed the patent to over 40 different companies, and has pending litigation against almost 40 more, including Microsoft.
"Forgent Networks is a classic example of the new and rapidly growing trend of patent holders that do nothing more than sue people who make products or services available to the public," said Dan Ravicher, Executive Director of the Public Patent Foundation (PubPat), which lobbies against the current patent system.
"Unfortunately, the patent system allows for such perverse behaviour because it cares more about patent holders than it does the public," he added.
On Wednesday PubPat announced that it had filed a formal request with the US Patent and Trademark Office to revoke the ‘672 patent, on the grounds of prior art – that the feature being patented was already in the public domain.
"CLI is using the '672 patent to harass anyone that implements the Joint Photographic Experts Group ('JPEG') format," states the request. "CLI's aggressive assertion of the '672 patent is causing substantial public harm by threatening this international standard on which the public relies."