TDVision Wants to Fill Up Cable's 3DTV Glass

TDVision Systems is pitching the cable industry and its key video suppliers on a patented technology that can produce full-resolution 3DTV signals without blowing out MSO bandwidth budgets. Comcast, DirecTV, Cablevision and others are starting off with "frame-compatible" formats that knit together two half-resolution, high-definition TV signals that can be fed to today's digital boxes. Comcast kicked off its stereoscopic 3DTV efforts in April with coverage of The Masters golf tournament using MPEG-2, but is now requiring consumers to get MPEG-4-capable boxes to access ESPN's new part-time 3D channel.

Offering frame-compatible, half-resolution 3DTV signals also keeps bandwidth requirements in check, since they take up roughly the same space as a linear 2D-HD channel, plus an overhead encoding premium in the neighborhood of 10 percent. Offering 3D MPEG-4 format offers even more savings.

But in the future, full-res 3DTV is expected to cost a much heavier premium. Estimates vary, but TDVision chief marketing officer Ethan Schur says a linear, full-res 3DTV channel, without using any special techniques, could more than double the bandwidth requirement if operators intend to deliver HD to each eye. On top of that, the operator may still need to set aside another channel if it intends to simulcast any 3DTV programming that can still be displayed on older 2D-only TVs.

The Bridge to Full-res 3DTV
TDVision is starting to come on the cable radar as the industry continues along an "interim" path with frame-compatible 3DTV. The first phase is already underway with half-resolution signals. The next phase is expected to help take some of the manual settings out of the equation and make sure that TVs and set-tops can toggle between 3D and 2D programming on the fly.

TDVision's interest in cable (and perhaps vice-versa) will grow as the industry starts to pursue full-resolution 3DTV and the use of Multiview Video Coding (MVC), a bandwidth-saving compression technique that's already been applied to H.264/MPEG-4 AVC, and has been adopted by Blu-ray for its 3D spec.

Schur claims TDVision's technology, when linked to the MVC process, can result in big bandwidth savings. He says operators will be capable of delivering a full-resolution 3DTV signal (plus the 2D-compatible version) on one stream and require a bandwidth penalty of about 35 percent -- versus the 215 percent required for a full-res 3D and a simulcasted 2D version.

TDVision claims it can offer this sort of encode-once/deploy-everywhere process using what it calls the "2D+Delta System." The company plans to demonstrate it at next month's CableLabs Summer Conference in Keystone, Colo.

As described, the patented system saves on bandwidth during the encoding process by combining the left-eye and right-eye view and throwing out the similarities between the two. The anticipated 35 percent bandwidth penalty represents the 3D "delta" information that's compressed and stored in the video stream alongside one of the views as the 2D version.

In 2D mode, the TV set would only decode the delta-free left-eye version and ignore the 3D info. A 3D-capable TV would also decode the 3D info to create the full-resolution 3D image. The good news for operators, then, is that they would only have to send a single broadcast stream to all customers, rather than simulcasting 2D and 3D versions of the same content.

Schur hopes the process will help 3DTV gain mass adoption among consumers and give studios a way to enter the third dimension without having to produce versions for the 2D and 3D audience. One likely exception to that is sports programming. Different angles are needed to enhance the 3D effect, which is one reason why ESPN is producing its 3DTV programming separately.

Blu-ray is already using some of TD Vision's intellectual property in its 3D specs, but it's also trying to fit into cable's encoding and decoding ecosystem as it prepares to join the full-res 3DTV era.

According to Schur, Magnum Semiconductor is making a headend encoder that integrates TDVision's 2D+Delta System. But the deal's not exclusive, so anyone can license TDVision's technology. He says the chips being used by major TV manufacturers will be able to decode streams that use the vendor's technology, and hopes the same will be true for next-gen set-tops that will be capable of decoding full-res 3DTV signals.

But how soon will cable's move into this phase of 3DTV begin? Schur thinks it will start happening within the next six months, noting that some will be "surprised" at how quickly cable moves in this respect.

"But the first thing that's important is getting the encoders in there. The next step is to include the support in set-tops coming into the market," he says.

But TDVision, a privately held firm with under 20 employees, won't be the only one charging into that market. Dolby Laboratories and RealD have both started off with frame-compatible solutions and are looking at ways to make the jump to full-res 3DTV.

By Jeff Baumgartner, Light Reading CABLE