Invisible marks that can be used to trace illegal copies of television shows and movies will be embedded in programs available on demand across the country using technology from Widevine Technologies.

Widevine, based in Seattle, said Tuesday its invisible digital markers would be embedded in programs distributed to cable companies served by TVN Entertainment Corp., a Burbank-based company.

Among TVN's cable customers are four of the nation's largest operators: Comcast Corp., Cox Communications Inc., Charter Communications Inc. and Adelphia Communications Corp.

Digital watermarks are not visible to the naked eye, but contain information about the origin of the program. They allow Hollywood studios to track shows as they are distributed to cable boxes, TV sets, computers, cell phones or other devices.

The watermarks remain even after the program is copied several times, allowing law enforcement to tell where illegal copies were obtained.

TVN provides movies, concerts and other programs to cable operators and telecommunication companies, who then offer them to consumers for a pay-per-view fee.

Tuesday's announcement marks the first time digital watermarking has been used to track such programs.