While cable operators can deliver 3DTV today in a "frame compatible" mode to viewers, there is still a considerable amount of work and research left to be done to improve the experience and quality of a stereoscopic video delivered to the home, industry experts said on a panel here at the Cable Show.
The cable industry's current approach is to deliver frame-compatible 3DTV signals, which don't require significant changes to the video-delivery infrastructure. The left- and right-eye images are delivered either in a side by side or stacked top/bottom.
In a second phase, full-resolution 3DTV will be delivered via two separate channels of information, using either a frame-compatible signal plus an additional channel of information, or a single-image signal an additional channel with 3D information. But that will require new delivery equipment and set-tops.
"The end game is of course to deliver full resolution [3D]," said David Broberg, CableLabs vice president of consumer video technology. Set-tops with the additional processing power required to handle 1080i HD resolution in 3D are probably two years away, he added.
The panel, "Depth Perceptions: Technical Approaches For 3D Video Integration," was moderated by Comcast chief technology officer Tony Werner.
Others enhancements that aren't technically necessary but will improve 3DTV include being able to deliver on-screen graphics (including closed captions) in 3D and instructing the TV to switch between 2D and 3D modes, said Kevin Murray, systems architect with NDS Group.
"You don't need to do anything to an HD set-top to get 3D video on a 3D display... but the experience you get isn't as seamless, isn't as clean," he said.
Trick modes -- e.g., fast forward -- are also problematic in 3D and need to be considered separately, Murray said. Video of somebody throwing a baseball at you in 3D in fast-forward mode can become very disconcerting, he noted.
And there's still the question of how popular 3D content will prove -- and whether programmers will spring for the additional production expense to deliver 3D content in the near term, said Walt Husak, Dolby Laboratories' director image technologies.
"How many hours will people spend viewing 3DTV - five to six hours per day?" he said. "Or will it be a couple hours per week? We'll have to wait and see."
Meanwhile, glasses-free 3D displays may be many years away.
Mark Schubin, an independent TV technology consultant and a Society of Motion Picture and Television Engineers fellow, described a demo by Japan's NHK showing an "absolutely great" 3D parallax-barrier display -- which require no glass -- but even with an 8K camera "the quality was less than YouTube" because the technology displays images from multiple viewpoints. He estimated a parallax-barrier display would need 100 times the information that is currently transmitted for 3DTV to get a high-quality video.
Broberg said glasses-free 3D displays may hold more promise for single viewers, in a handheld device. "It's not something you can share but it can provide a fairly good, high-quality personal 3D view," he said.
Werner, for his part, noted that Comcast recently carried the first national broadcast of 3D content with The Masters in April.
"I thought it was going to be a little ho-hum," he said. But at the viewing events the MSO hosted, "we were almost having the rip the glasses away from people."