By Kasper Jade and Katie Marsal

Published: 01:00 PM EST

A near three-year-long attempt by Apple Computer to patent the menu-based software interface of its popular iPod digital music player has ultimately proved unsuccessful, AppleInsider has discovered.

The company's patent application, which lists Apple vice president Jeff Robbin and Apple chief executive Steve Jobs as two of its primary inventors, received a final rejection last month from the United States Patent and Trademark Office.

Standing in Apple's way appears to be a prior filing by inventor John Platt, who submitted a patent application for a similar software design for a portable device in May of 2002 -- just five months before Robbin submitted his claims on behalf of Apple.

Platt's application describes his invention as a system or method that "generates playlists for a library collection of media items via selecting a plurality of seed items, at least one which is an undesirable seed item." The process by which the iPod's software displays its own menu-based interface is very similar to the process Platt's filing goes on to describe.

In an attempt to trump Platt's application, Robbin through his patent lawyer petitioned the patent office to review an amended set of claims last November, shortly after his initial filing had been rejected in light of Platt's.

Upon review, the patent office in July issued a 6-page document pointing to prior claims made by Platt and offering its final rejection of Robbin's application. In forming a basis for the rejection, an examiner for the patent office began by citing Platt's preexisting claims:

"Platt discloses an apparatus and a method of assisting user interaction with a multimedia asset player by way of a hierarchically ordered user interface, comprising: displaying a first order user interface having a first list of user selectable items; receiving a user selection of one of the user selectable items; and automatically transitioning to and displaying a second order user interface having a second list of user selectable items based upon the user selection."

It's unclear how Robbin and Apple will proceed in their attempts to secure rights to the iPod's software design interface. The United States Patent and Trademark Office allows a three-month window period for reply to the final rejection, in which Robbin and Apple can appeal the decision, request reconsideration, or file a continuation of their original application.

With the fuses burning short on a number of patent filings from the early evolution of digital music players, it has yet to be determined who will ultimately score ownership in the industry. As it stands right now, Robbin's iPod software design is open territory that Apple cannot necessarily protect others from duplicating.

Prior to working alongside Jobs on Apple's iPod team, Robbin was employed by Casady & Greene, a small software company which developed applications for the Mac OS platform.

Casady & Greene was widely known among Mac users for its SoundJam MP3 player software, which Apple eventually took control of and re-branded as iTunes after hiring Robbin. In his first role as an engineering manager at Apple, Robbin was credited with leading the iPod's software development in the early days of the project.