Following Steve Jobs' open letter criticising digital-rights management (DRM) technology, one of the four major record labels acknowledged that the lack of interoperability between competing music players and online services had become a growing problem for consumers.

Meanwhile, the recording industry's trade group urged Apple to license its FairPlay DRM to other companies, and one of the iTunes Store's biggest rivals called the advent of DRM-free online music inevitable.

All this came a day after the Apple CEO published an open letter on Apple's site saying that his company would sell DRM-free music through the iTunes Store if the "big four" music companies — Universal Music Group, Sony BMG, Warner Music and EMI — were to allow it.

Jobs also urged critics of DRM systems to "redirect their energies towards persuading the music companies to sell their music DRM-free."

At least one of the companies spoken with has experimented with offering DRM-free music online. EMI has released DRM-free MP3s through Yahoo's online service, offering several tracks by Nora Jones and Relient K in December.

"The results and the feedback have been very positive," said EMI spokesman Adam Grossberg.

EMI's experiment came at a time more consumers and governments are complaining that music purchased online is tied to specific music players. iTunes downloads, for example, will only play on iPods.

"We believe the lack of interoperability between platforms is becoming a increasing concern for consumers," Grossberg said. "EMI has been engaging with its partners to find a solution to this problem"

Sony BMG declined an opportunity to comment on Jobs' letter. The two other major record labels, Universal and Warner, could not be reached for comment as this story went to press.

While positive feedback doesn't necessarily mean the music industry will embrace DRM-free online sales, one iTunes competitor, Rhapsody operator RealNetworks, believes DRM-free music will happen.

"We think it's just a mater of time," said Dan Sheeran, Real Networks senior vice president of music. "It's largely a matter of everyone being comfortable with it."

RealNetworks is no stranger to the concept of DRM-free music. The company says it's been working with music companies for several years, encouraging them to drop the restrictions from digital downloads. Rob Glaser, chairman and CEO of RealNetworks, has also been outspoken on the issue.

"Two weeks ago at the MIDEM International music conference, we called on the major labels to drop DRM for digital music purchases," said RealNetworks chairman and CEO Rob Glaser. "Doing so would be the right thing for consumers and would also be good for everyone in the industry. It's great to see other industry leaders support this message."

RealNetworks executives also agreed with a sentiment expressed by Jobs — that DRM systems do little to stop the theft of music. "The committed pirate is still going to get what they want," Sheeran said.

"There is always going to be piracy," he added. "The main question is will it be the majority or minority of the activity."

DRM supporters contend dropping the technology would lead to more piracy and illegal file-sharing. However, RealNetworks believes the opposite could be true if the industry takes the time to educate the consumer and make the digital experience better.

"We believe that piracy has continued because DRM has made the experience worse than if you buy a CD," Sheeran said. "With DRM that's not true because you can't play it on other devices. Most consumers don't want to be pirates, but until we make it a better experience, a lot of consumers will continue on the other path. Ironically, this could lead to less piracy."

The Recording Industry Association of America (RIAA), however, believes that the answer lies not in eliminating DRM but in making existing technologies work together better.

"We all want to see this marketplace work and for fans to enjoy the music they have lawfully bought on various devices or services," the music-industry trade group said. "The issue is how. One way to achieve it was outlined by Steve Jobs in his post — for Apple to license its DRM to other technology companies. We think that's a great solution."

Jobs did mention the possibility of Apple licensing FairPlay to competitors in his letter, only to dismiss the option out of hand due to Apple's concern that such a move would inevitable lead to leaks of proprietary technology.

"Such leaks can rapidly result in software programs available as free downloads on the internet which will disable the DRM protection so that formerly protected songs can be played on unauthorised players," Jobs wrote.

The RIAA dismissed such concerns in its statement: "We have no doubt that a technology company as sophisticated and smart as Apple could work with the music community to make interoperability happen."