Sonic's patent, filed in 1998, relates to certain techniques for "digital multimedia composition." Among other applications, the patent covers improved ways to create digital videos using a graphical "storyline" to sequence individual video segments.
Filings with the U.S. District Court for the Eastern District of Texas are available at www.txed.uscourts.gov. The full text and images of U.S. Patent No. 6,204,840 are available at www.uspto.gov.