Video software developer Gotuit Media has sued Microsoft, claiming that its Silverlight multimedia software infringes several of the company's patents.

Gotuit Media filed the suit last Wednesday in US federal court in San Francisco, claiming that Silverlight infringes on three Gotuit patents, which cover ways of making videos searchable on the Internet.

Released last year, Silverlight is Microsoft's alternative to the Flash and QuickTime multimedia formats. Heavily promoted by Microsoft, it lets Windows users watch video or animated graphics through their browsers.

Gotuit sells software that lets users add text data to video clips, making it possible to search and sort through videos for the parts they want. The software has been used on several high-profile Web sites including those of Sports Illustrated and the National Hockey League.

In court filings, Gotuit says Silverlight infringes on its patents because it too gives users a way to enhance video with "metadata tags in order to enable video search and navigation and provide a personalized viewing experience."

"Microsoft has infringed and is still infringing the patents," Gotuit says in its complaint.

The company cites Microsoft's upcoming on-demand video coverage of the Beijing 2008 Olympic Games on NBCOlympics.com as infringing behavior because this Web site uses Silverlight to tag video and make it searchable.

The suit seeks an injunction preventing Microsoft from using this technology and asks the court to award damages and legal fees.

Founded in 2000, Gotuit counts Motorola and venture capital firms Highland Capital Partners and Atlas Venture among its investors.

The Woburn, Massachusetts, company's outside counsel, Spencer Hosie, declined to comment on the lawsuit.

Reached last Thursday, a Microsoft representative was unable to comment on the suit.