3D Delivery From Venue to Viewer
Despite the wealth of attention given to the capture and production side of the 3DTV equation, distribution and delivery have been largely swept under the rug as 3D technology continues to wade into uncharted waters. At the Content & Communications World 2010 this week, leaders from the cable, satellite, and transmission fields gathered to discuss the contribution and distribution challenges that broadcasters and operators face in delivering content from the “venue to the viewer.”
“Most of the time, [3D] distribution to our customers is actually very simple,” said Hanno Basse, SVP of broadcast systems engineering for DirecTV. “We only had to make a few revisions in our set-top–box software so all of our existing MPEG-4 HD boxes could receive 3D and output 3D. We just had to work around a few graphics problems, but, other than that, we’re there.”
Three Dimensions, Half the Resolution
In order to distribute 3D within their current infrastructure, satellite and cable providers have used the frame-compatible 3D format, which carries separate left and right video signals within the video frame used to convey a conventional 2D HD signal, squeezing them to fit within the space of one image. While this allows operators to utilize existing set-top boxes (with a software update), it also essentially cuts the video resolution in half.
“The reason we adopted frame-compatible was that we could put it on our plant without making major changes to any of the infrastructure,” said Dan Holden, fellow and chief scientist, Comcast Media Center. “The problem is, once you take 3D video and you cut the resolution in half, there is no way to get that resolution back to that full quality that came from the venue. As we look to the future, we want to get to full-resolution 3D, just like everybody else in the industry, but that is a ways off.”
One Step Forward, One Step Back
Although frame-compatible delivery has allowed 3D programming to enter the home, it may have also created a brand-new obstacle on the road to full-resolution 3DTV.
“By trying to get 3D on the air immediately, we have actually created a new legacy format, this frame-compatible format,” said Matthew Goldman, VP of technology, Ericsson. ”For a number of years, even when full-resolution 3D comes out, there will be lots of systems out there that can still respond only to frame-compatible 3D. We didn’t have to change the existing infrastructure with frame-compatible, but, with full-resolution, we will have to.”
A Multitude of Standards
The chief issue in the delivery of full-resolution 3D remains the lack of true standards for contribution and transmission. Broadcasters, operators, and consumer-electronics manufacturers must make a variety of format decisions when it comes to 3D: side-by-side or top-and-bottom, 1080i or 720p, and a host of others. This has made it difficult for the 3D ecosystem to come to an agreement on standards, which are necessary to spark the rollout of next-generation set-top boxes capable of full-res 3D.
“The question of standards and different formats is confusing the hell out of everybody: TV manufacturers, the HDMI consortium, and even us [satellite and cable operators],” said Basse. “This is not helping anybody. It’s definitely not helping anybody sell TVs, and, let’s face it, that’s really what 3D is all about right?”
Unfortunately for Basse and his fellow operators, a set of 3D standards looks to be a long way off. Although an MPEG subcommittee is currently in the process of setting such standards, results are most likely years, not months, away.
“I would guess that it’s probably going to take three years before we’ll see a standard come out of that body,” said Holden. “Then, it will be another year or two by the time it’s deployed to the consumer. So, if we say it’s five years before MPEG can give us a full-res–3D standard or option, there are definitely a few things we’ll need to look at in the interim.”
Is Full-Res 3D Worth It?
Perhaps the biggest question whether full-resolution 3D is even worth all this fuss. Many argue that the actual viewer benefit of full-res is minuscule or even imperceptible.
“I don’t think there is a huge difference between frame-compatible resolution and the full resolution,” said Basse. “I’m not sure that there is any real tangible benefit for the consumer. Whether people are actually going to see the difference between the frame-compatible and the full-resolution formats is debatable.”
Holden concurred: “I’m not totally sure that full-resolution offers a huge advantage over half-resolution frame-compatible. We’re evaluating that in our lab. I don’t know if that means a 10%, 20%, 50% increase in video quality. But, until we actually set some of these proposals or proprietary solutions up for what we’re doing today, I’m not sure there is a real advantage to go there.”
The Holy Grail: Turning a Profit
Although frame-compatible delivery has provided a temporary solution for the distribution side of 3D, financial viability for 3D broadcasts remains a long way off.
“Right now, there are more than a dozen proposals out there on how to do [deliver 3D], “ said Goldman. “But I know all of us can agree on one thing: we have to make this economically viable. That is the holy grail.”