TV Networks Differ on Digital

ABC and CBS on Thursday selected different standards for digital television, indicating that broadcasters likely won’t reach a consensus on how they’ll use the new technology that promises sharper pictures and better sound.

CBS said it will begin airing five hours of prime-time shows later this year with the method that allows the highest picture quality. ABC, meantime, plans to broadcast lower-resolution images, which may allow it to squeeze another channel onto the air.

The networks are the first to formally say how they’ll transmit digital TV, and their decisions may influence how the nation’s 1,600 stations will upgrade their systems. About 26 stations in the 10 biggest markets have to start airing digital signals by November, changes that could cost them $1 million to $12 million for new equipment such as digital cameras and transmitters.

“They have to see what the advertisers are thinking and what consumers will think. All of this will take time,” said Bishop Cheen, analyst at First Union Capital Markets.

The networks can choose how they use the digital licenses they received from the Federal Communications Commission last year. They can offer sharper, movie-quality images in one channel, or divide the space into multiple channels of lesser-quality resolution, which could allow them to offer pay-per-view services.

They must also choose the technical standards used to transmit programs. The computer industry has been pushing broadcasters to adopt a so-called progressive standard because those images can also be displayed on PC monitors. Broadcasters currently transmit using a method called interlace scanning.

ABC said it will use the progressive method to transmit prime-time shows in a format that uses 720 lines on the TV screen. That’s more than the 525 lines consumers currently see, though less than the best resolution possible.

The 720p standard doesn’t use as much capacity as a higher-resolution format, giving the network room on its signal to air other channels.