Last year, RealNetworks released a technology called Harmony that for the first time let copy-protected songs from a music store other than Apple's iTunes play directly on the iPod. RealNetworks had independently mimicked the antipiracy tools used by Apple and hadn't gotten Apple's permission first.
Apple called the company's actions "hacker tactics" and a few months later changed its software to break the compatibility, at least on iPod Photo devices. On Tuesday, a RealNetworks executive said his company had re-established compatibility with all iPods.
"Harmony now supports all shipping iPods, including iPod Photo," said RealNetworks Chief Strategy Officer Richard Wolpert.
The technology tussle, which focuses on a relatively small portion of RealNetworks' music business, nevertheless aims at the heart of one of the most controversial issues in online music.
Incompatibility between the major download stores and music players has fragmented the digital market. For example, songs purchased from Apple's iTunes store can only be played directly on Apple's iPod, while songs purchased from Napster or Microsoft cannot be played on the iPod.
Record company executives have been bitterly critical of this balkanization, and have asked technology executives--primarily Apple CEO Steve Jobs--to reconsider their technology decisions. As yet, no broad move toward compatibility has emerged.
RealNetworks' Harmony software, which allows songs to be played directly on an iPod or on a Microsoft-based device, is limited to the company's pay-per-song store. Songs downloaded through the new Rhapsody portable subscription service are compatible only with a small number of Windows-based MP3 players.
An Apple representative could not immediately be reached for comment.