A federal judge on Thursday tossed out more than a dozen patent infringement claims filed against Microsoft by Google-owned Motorola Mobility.

US District Court Judge James Robart, in Microsoft's home state of Washington, sided with the software colossus, dismissing 13 claims of infringement on a trio of Motorola patents involving digital video encoding and decoding, according to court records.

The Motorola patents were evidently not specific enough regarding the computer code involved, according to the documents.

The decision significantly narrowed the case.

If the remaining claims survive a similar legal challenge, Microsoft would likely be entitled to pay a reasonable rate to license what is considered a "standards-essential" technology, according to intellectual property specialist Florian Mueller, of FossPatents.com.