Lucent Technologies has filed a patent infringement suit against Microsoft over the same MPEG-2 decoding technology at the center of a 2003 legal dispute. According to the formal complaint, filed March 28 in U.S. District Court in San Diego, the telecommunications equipment maker is suing Microsoft for patent infringement against Patent No. 5,227,878, titled "Adaptive Coding and Decoding of Frames and Fields of Video," which was issued to Lucent in 1993. The patent concerns MPEG-2 video encoding.

In 2003, Lucent filed infringement cases against Dell and Gateway over several patents, including No. 5,227,878. Because of its indemnity agreements with the companies Lucent was going after, Microsoft filed a countersuit against Lucent that same year. Although Microsoft won several patent infringement claims on summary judgment, the claim concerning Patent No. 5,227,878 was dismissed without prejudice (meaning the lawsuit can be filed again if the problems are fixed) because of a typographical error in Lucent's patent.

Full story: ZDNet News