HDMI Tackles 3D TV

HDMI Licensing, LLC, the licensing entity behind the High-Definition Multimedia Interface networking technology that is commonly used to provide a secure digital connection between digital TV sets, set-top boxes and Blu-ray players, is working to ensure that television programmers will be able to deliver upcoming 3D broadcasts to new 3D-capable HDTV sets.

The organization, which licenses its technology to over 900 consumer electronics (CE) manufacturers, announced that it is making the 3D portion of its latest HDMI specification, version 1.4, available for free public download so that television networks and transmission vendors can get the necessary information to deliver compatible 3D pictures to new 3D sets.

Such companies haven't traditionally been licensees of HDMI technology, and thus didn't have access to the confidential specification that identified 3D formats. But they need to know how the 3D parts of HDMI work to ensure that early 3D broadcasts are viewable, says HDMI Licensing president Steve Venuti, which is why the organization is making the information freely available.

"I see it as a necessity because HDMI is leading the market in supporting 3D at home," says Venuti. "These companies don't want to pay to get the spec, but they need it to understand how 3D will work in the marketplace."

The HDMI Consortium also plans to include multiple broadcast 3D formats in an upcoming specification, version 1.4a, to ensure that HD sets and set-tops can display networks' nascent 3D programming.

HDMI Licensing, founded by a consortium of Hitachi, Panasonic Corporation, Philips, Sony, Thomson (RCA), Toshiba, and Silicon Image, had already addressed the growing momentum behind stereoscopic 3D technology by including 3D gaming and movie (Blu-ray) formats in HDMI version 1.4, which came out last June. But that specification didn't include broadcast 3D formats, explains Venuti, mainly because the organization didn't expect television networks like ESPN and pay-TV operators like DirecTV to move to launch 3D by mid-2010.

"We've really seen a rush of 3D devices, but when we when launched 1.4 in June, it was very unclear what formats would drive content to the home," says Venuti. "So we mandated a game format and movie format, and said if you build a system with HDMI, you have to have them. But we left out a broadcast format, because we didn't know where the market was going with that. Since then, broadcasters have stepped up the game quite a bit, and there's been a lot of movement in the HDMI Consortium to match the 3D release of broadcasters."

In fact, in December the HDMI Consortium announced that it would ease some of its licensing restrictions to allow existing late-model set-tops to deliver 3D broadcasts to new 3D HDTV sets, without having to support the mandatory movie or gaming formats in HDMI version 1.4. Specifically, it decreed that set-tops with HDMI version 1.3 could receive a firmware upgrade that would enable them to connect to a new 3D set with HDMI version 1.4 to display a number of 3D HD broadcast formats. That is how satellite operators DirecTV and BSkyB plan to deliver 3D to their existing high-end set-tops. Venuti said that Sony PS3 game consoles can support 3D in the same way.

"That's going to enable the existing infrastructure of source devices to pump 3D content, and you're going to need a 3d-enabled TV to view it," says Venuti.

The HDMI movie format that will be used by new 3D Blu-ray players specifies the delivery of two full 1080-line-progressive/24 hertz (1080p/24) pictures, one for each eye, which requires a significantly higher bit rate than normal 1080p/24 video. But the "frame-compatible" broadcast formats that HDMI Licensing is currently addressing are designed to work within the existing bandwidth for HD transmission by using spatial compression to reduce the horizontal or vertical resolution of the picture. That is a compromise that networks and pay-TV operators can currently live with, as adopting "full 3D" would require doubling the bandwidth used to deliver HD to the home.

The 3D compression techniques described by HDMI Licensing as "informative formats" include Frame Packing; Field Alternative; Line Alternative; Side-by-Side (Half); Side-by-Side (Full); Left + Depth; and Left + Depth + Graphics + Graphics-depth. The organization also announced in December that it will add the "Top/Bottom" frame-compatible technique, which ESPN plans to use for its 720p 3D HD pictures, to the updated 1.4 specification.

Venuti says the HDMI version 1.4a specification, which will make the support of such broadcast formats mandatory in new 3D-enabled CE devices, should come out soon. He notes that a pay-TV operator's set-top could support as little as a single broadcast format, such as 720p top/bottom, but that 3D sets will have to support all broadcast formats to ensure interoperability.

"We hope that will provide leadership and guidance to the broadcast world," says Venuti. "We don't expect it to be the way to deliver 3D content forever. But at the least, it's a minimum way to support interoperability."

By Glen Dickson, Broadcasting & Cable