LOS ANGELES -- The firm behind the defunct Qtrax online file-swapping network has inked a licensing deal with Britain-based EMI Music Group PLC and aims to relaunch later this year as an ad-supported recording industry-friendly online music service.

Qtrax was among several peer-to-peer file-sharing applications that emerged following the shutdown of Napster, the pioneer service that enabled millions to illegally copy songs stored in other music fans' computers.

Creator LTDnetwork Inc. stopped distributing Qtrax after a few months following its 2002 launch to avoid potential legal trouble.

The new version of Qtrax will still let users to tap into the Gnutella network to search for music, but will use technology to block any copying or distribution of music restricted by record labels.

Instead, users will be able to play such songs a handful of times for free, but additional listens will require them to purchase the song for about a dollar. They may also download unlimited, though not permanent, licensed music by paying a monthly fee.

While labels are eager to find new avenues for music fans to purchase music, enticing fans accustomed to free and unrestricted file-sharing networks to switch to restricted services such as Qtrax remains a challenge.

"Maybe there's a small percentage who say 'we must have completely unfettered access to free music', but the reality is being able to listen to a song five times is not too bad, right?" said Allan Klepfisz, president and chief executive of New York-based Brilliant Technologies Corp., which acquired LTDnetwork about a year and a half ago. "You get a pretty good sense of whether you want to purchase it."

Pricing for the subscription tier of the service has not been finalized yet, but likely will be comparable to that of other online music services, which typically charge between $10 and $15 a month.

Record labels who license content for Qtrax will receive half the revenue from ads displayed during free song previews, said Mr. Klepfisz.

So far, EMI is the only major label to reach a Qtrax licensing deal, but Mr. Klepfisz said he is pursuing licensing talks with other major labels and expects to launch Qtrax in the United States as early as the third quarter of this year.

IMesh, an established file-sharing operator that shut down in 2004 and relaunched last fall as a licensed music service, has declined to say how many users it has.