Apple last night partially failed in its bid to have's iPod-focused patent infringement lawsuit thrown out of court. claims that some of its patents for receiving, storing and transmitting audio and video files are at the heart of the iPod.

The company first approached Apple to try to arrange a license for its claimed patents in late 2004. These attempts failed and the company later launched litigation against Apple in April 2006.

Apple has argued that the patents do not rightfully belong to Burst, or that the patents are invalid. Last year Burst settled litigation with Microsoft, which took a licence and paid Burst a $60m lump sum.

Apple took that argument to the courts yesterday, seeking a ruling to invalidate parts of four of Burst's patents. US District Judge Marilyn Patel did invalidate some elements of's patents, but upheld others, meaning the case must now move on to an out-of-court settlement, appeal or trial.

In a statement on the website, the company says: "Judge Marilyn Hall Patel of The United States District Court, Northern California, today issued an order that invalidated as obvious or anticipated 14 claims in the patents in suit between Apple Computer and,. The order leaves 22 claims remaining, claims that the court did not find as invalid or anticipated. These remaining 22 claims include some significant audio and video claims that reach key Apple products including the Mac. Burst looks forward to trying its case in court against Apple early next year."

Apple does not comment on ongoing litigation.