DVDs create sharper images than videotapes and have steadily displaced the older medium. Yet movie studios are trying to spawn a newer market by producing even higher definition video.

Disk makers have released two competing high-definition formats: Blu-ray and HD DVD. The technical press is comparing the battle with the late-1970s match between VHS and Betamax videotape standards. But the current contest may play out differently: some manufacturers are making machines that can play both formats, and Warner Brothers has announced that it will soon release movies recorded in both schemes on a two-sided disk.