By this time next year, new coding on music CDs might prevent them from being copied on CD recorders?both those in PCs and in standalone audio CD recorders. And because of this same coding, audiophiles whose high-end components send a digital signal from their CD players to a receiver or amplifier for better digital-to-analog conversion might find their systems reduced to the level of regular players with only analog outputs.

These potential limitations are part of the AudioLok Red copy-protection technology being developed by U.K.-based C-Dilla, a subsidiary of Macrovision whose anti-copy system currently prevents videotapes, DVDs, and pay-per-view movies from being recorded on VCRs. AudioLok blocks a PC’s CD-ROM drive from playing music CDs, thereby foiling attempts to copy them or post them on the Internet.

AudioLok tricks CD-ROM drives into treating the disc as faulty by writing intentional errors on the CD. Audio CD players ignore these and play the disc as normal. But CD-ROM drives, with more stringent error detection for PC data, reject the CD as unreadable.

C-Dilla also claims that it can prevent AudioLok discs played in regular CD players from being copied on audio CD recorders—although the company doesn’t say how. But since audio CD recorders lack the ability to copy CD-ROMs, passing the signal directly through the CD player’s digital outputs with the decoy errors intact would foil recording. But this AudioLok application is likely to infuriate consumers, since the price of their audio CD recorders and blank audio CD discs includes a royalty payment for the privilege of making digital recordings of copyrighted works.

Meanwhile, other AudioLok errors transmitted in the digital signal from a CD player’s optical or coaxial output jacks could prevent the signal from being decoded by the high-end digital-to-analog converters that are integrated into top-shelf audio receivers and amplifiers. The fact that Audiolok can render these products inoperable will likely elicit a challenge from the electronics industry, which regularly opposes any technology that would defeat product functions consumers have paid for. Stephen A. Booth, October '99