Migrating to advanced video coding—What's the plan?

Mon, 10/31/2005 - 7:00pm
Jeffrey Krauss, President of Telecommunications and Technology Policy

It's no secret that something better than MPEG-2 video compression is emerging. In fact, there are two video coding methods that are better. Both AVC (also known as MPEG-4 Part 10) and VC-1 are better. They can provide the same picture quality as MPEG-2 in about half the bandwidth. So a TV broadcaster, instead of using a full 6 MHz channel to carry an HDTV program, could use that channel to carry both an HDTV program and a bunch of SDTV programs. It's technically feasible. But neither broadcasters nor cable operators nor TV manufacturers have figured out how to get to AVC or VC-1 from where we are today.

Broadcasters have staked their claim to an approach that retains the same data rate, 19 Mbps, in their 6 MHz channel, but uses a kind of time division multiplexing to interleave signals using MPEG-2 coding with signals that can use advanced coding. This approach allows "legacy" receivers to ignore the signals with the advanced coding. But it eats into a broadcaster's payload capacity.

Broadcast satellite operators have plans to use advanced coding in the near future, and have actually selected AVC as the one they plan to use. They have a more urgent need to migrate to advanced coding because otherwise they would not have the capacity to carry all the HDTV programming—both satellite services and local broadcasters—that is expected in the next few years.

For the most part, existing consumer electronics hardware can't decode AVC or VC-1. So that means new hardware must be introduced. There are currently about 18 million DBS subscribers, so a lot of new set-top boxes will be needed. But DirecTV and EchoStar can manage their rollouts on a region-by-region basis because of new spot-beam satellite technology. And they can use rebates and tie-ins in the same way that cellular operators do—a free set-top box if you sign up for a two-year subscription.

Cable operators don't feel the same pressure to increase their network capacity by moving to advanced coding. But that could change. If it does, advanced coding can be deployed system by system, using new set-top boxes to do the decoding. But as cable-ready ("plug & play") digital TV receivers are deployed more widely, the cable industry's ability to introduce new technology like advanced coding becomes more constrained.

Jeffrey Krauss
Jeffrey Krauss
President of
&Technology Policy
Broadcasters, however, don't have a business plan based on set-top boxes. They broadcast directly to TV receivers. According to the Consumer Electronics Association, 7 million DTV sets were sold in 2004 and an estimated 15 million will be sold in 2005. That's at least 22 million "legacy" TV sets, once advanced coding is deployed. They'd all have to be replaced in order to decode and view programming that is transmitted using advanced coding.

But, the question is—replaced with what? Consumer electronics manufacturers are reluctant to produce TV sets with new technological capabilities until broadcasters commit to use and promote the use of those capabilities. And, broadcasters can't use new technology if their viewers don't have the hardware to receive it. It's a real chicken-and-egg problem.

And then there's the marketplace confusion factor. You go to Best Buy and you see two DTV receivers side by side, and the only difference is that one decodes MPEG-2 and AVC and the other decodes only MPEG-2. Which one do you buy? Maybe it depends on the price difference. Maybe you don't buy anything, but instead go home confused. Or maybe you buy an analog set. Remember, even today, people are still buying analog TV sets. Who knows how long Best Buy will continue to sell them?

So suppose you buy the cheaper DTV set, the MPEG-2 set without the advanced decoder. You take it home, plug it in, and let the set search out all the channels. What does it do when it finds one carrying advanced coding programming? Hopefully it ignores that channel, and doesn't load those programs into the electronic program guide. Otherwise, you might decide to watch one of those programs, and the display would go dark when you tuned to it. But what if you see that very channel listed in the newspaper's printed program guide? How does one explain to a customer why he can't watch that program, especially a customer that just bought a new TV set?

The government will force the migration from analog to digital, because it wants to reclaim the analog spectrum. There won't be any such forcing to move from MPEG-2 to AVC or VC-1. But there are business considerations. Microsoft could subsidize the deployment of VC-1 decoders in TV sets. And it seems like IPTV services are leaning in the direction of VC-1. Decoder chip manufacturers don't seem to be worried about building chips that can decode both AVC and VC-1, along with MPEG-2. But they are worried that the royalty payments will be too high.

So here's the bottom line with respect to advanced video coding. The DBS guys have a plan. At least some IPTV guys seem to have a plan. Broadcasters and CE manufacturers are at an impasse, pointing fingers at one another, and nobody knows how to resolve it. Cable doesn't have a plan. Maybe it doesn't need one right away. But cable better have a couple of plans ready to go if it wants to remain the dominant entertainment medium.

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