Over the last two years, at least four companies -- Macrovision, Midbar Tech, Sony and start-up SunnComm -- have tried to persuade record labels to add various flavours of anti-copying technology onto ordinary CDs. But after an initial flurry of excitement, consumer backlash and stories of technological incompatibilities with some CD players and computers have kept sightings of copy-protected discs few and far between.

Record labels haven't abandoned the idea, however. In recent interviews, executives from several music companies have said they're still experimenting with the technology, but remain concerned about the technological glitches and consumer worries.

Macrovision and Midbar say the merger will help address those worries. By melding the two companies' products, they hope to be able to improve compatibility with computers. The companies also promise that by next year CDs using their joint copy-protection technology will include two versions of songs -- one for ordinary CD players, and one that can be loaded onto computer hard drives in much the same way that MP3s can be "ripped" or copied onto computers today. Listeners will not be able to make unrestricted copies of these alternate digital files, but the songs will be able to be transferred to mobile devices such as MP3 players and even burned onto CDs in a limited way, company executives said.

"We've kind of learned over the past year that consumers are really fighting this," said Brian Dunn, Macrovision's senior vice president of business development. "They want more flexibility."