SigmaTel, the digital chip maker (it supplies to iPod shuffle, among others) has bought out the software, patents and engineering resources associated with D&M Holdings’ Rio portable audio product line. Terms of the deal were not disclosed.

The Rio acquisition does not include any rights to ownership of the portable audio player products, inventory or trademarks associated with the Rio brand, SigmaTel said. It does, however, include as many as 15 patents and patent applications, some of which are among the earliest MP3 player patents ever granted and many of which have been granted or are pending in Europe and Asia.

D&M Holdings owns the Denon, Marantz, McIntosh Laboratory and the D&M Professional, ReplayTV, Rio and Escient brands.

Some more details in the release.