Macrovision is involved in an interference with InterTrust on a patent Macrovision acquired from MediaDNA, one of the many small DRM companies on the dot-com era. Reuters article on the dispute indicated that the mediaDNA patent was filed a mere 12 days before the InterTrust patent in dispute. In the US, this is not dispositive - the issue who was first to invent. Outside the US, in most jurisdictions, the first to file has a priority.
Who could be behind the curtain? InterTrust has sued Microsoft for infringement on many of the same patents, so a resolution of their validity could have a major impact on Microsoft. Reuters reports that Macrovision and Microsoft are working together on other issues, implying a connection. Normally, however, a company with an IP portfolio like Macrovision would be loathe to fall on its sword for a third party. Indeed, if Macrovision were to win, according to DRM Watch, it could turn around and sue Microsoft. More likely, this reflects the complex world of DRM patents, where the major players have been acquiring little companies for their patents, not their technology, and have begun to litigate the validity of their IP as another weapon in the ongoing battle for supremacy in the coming world of video on demand.