The company's lawsuit, filed Friday in U.S. District Court in Chicago, alleges that RealNetworks' RealOne Player Plus and Listen.com's Rhapsody service infringe on Friskit's technology. The suit could eventually ask RealNetworks and Listen.com for financial damages from sales of their players and subscriptions products, according to Friskit.
Friskit, based in San Francisco, said that if it succeeds in obtaining a permanent injunction, the companies would no longer be able to offer certain features in RealOne and Rhapsody. Those features include the ability for consumers to incorporate streaming media in personalized playlists in media players or to listen to a set of songs sequentially and continuously.
Neither RealNetworks nor Listen.com would yet comment on the matter.
"They haven't served the suit to us yet," said Lisa Amore, a spokeswoman for RealNetworks. A Listen.com spokesman said his company had been served the suit only on Monday.
Seattle-based RealNetworks in April announced the acquisition of Listen.com for about $36 million.