The patents cover locating song information in a database by creating a key from the music and delivering synchronized multimedia to a PC playing a particular song.
Such multimedia might include album art, lyrics and even advertising linked to a particular CD or song. Amazon.com and MTVi, among others, have signed up to use Gracenote's technology.
"The development and protection of unique and marketable intellectual property remain at the core of our business strategy," David Hyman, president of the Berkeley, Calif.-based company, said in a statement.
Gracenote is in a legal battle with a customer, music-software maker Roxio. It claims that Roxio contributed to the infringement of both its copyrighted database and its patents when Roxio decided to move to the publicly owned database Freedb.org.
With two more patents to its name, Gracenote has more legal muscle in its corner, said Gregory Aharonian, editor of Internet Patent News.
"An issued patent has tremendous uncertainty associated with it," he said. "Once someone gets a patent, other people have to alter their plans a bit."
Granted earlier this month, the two patents--numbered 6,230,192 and 6,230,207--bring the company's total to six.