But, said Lucent in its filing at the end of March, Microsoft has infringed this patent by releasing the Xbox 360 console, which has MPEG2 tech - it's alleged that's a breach of the Lucent patent.
When the judge made his ruling on the patent case with the typos last year, he said that the decision was without prejudice to Lucent starting a separate action.
And so it has. It filed the action on the 28th of March in the southern district of California, San Diego.
Lucent alleges Microsoft has infringed its patent and told the firm so soon after the intro of the Xbox 360.