A next-generation broadcast platform
I get tired of people saying the broadcast industry is full of dinosaurs. It gets under my skin sometimes. But the thought occurs to me that maybe it bothers me so much because it just might be true.
The pace of technological change in today’s world is astonishing, and being trapped by a 1990s paradigm of television might very well be the meteor crash that wipes us out. At the same time, the fact remains that viewers really like broadcast television. A simple, linear stream of high-quality content that is always on, easy to access and easy to use continues to provide great value for the vast majority of people. But I don’t think it’s a debate anymore that viewers’ habits are changing. Viewing continues to be more and more fragmented, both in terms of the content people are watching and the devices they are watching on. And perhaps more importantly, time-shifted viewing is making up an ever increasing slice of the viewing pie. So we’re left with a question about what we could change to better service our customers in today’s world.
That’s why so many in the broadcast technical community have been talking about what we could do from a technical standpoint to unshackle the chains so that we can continue to be players in the world of video information and entertainment. The idea of a next-generation broadcast platform using a new broadcast standard has been talked about for years, but what does that mean? If the industry is given a chance to reinvent itself technically, what should we strive to look like? For this article, I’ll focus on three areas of advancement that I think should be included in any new platform: improvements in the radio link, changes in video resolutions and codecs, and the ability to introduce advanced services.
As you look at the state of the art in today’s world compared to when 8VSB was adopted by the ATSC, you’ll discover that we actually have a very “bit-efficient” standard. That is, in terms of bits delivered per MHz used at a given C/N, the current system actually stands up surprisingly well. But the ATSC standard (ATSC A/53) has always had problems in reliably delivering those bits to a receiver when the propagation path has changing characteristics (multipath or Doppler).
Performance under those conditions is significantly improved when using the newer DTV Mobile broadcast standard (ATSC A/153), but that standard requires you to give up much of the bit efficiency that was inherent in the 8VSB system to start with.
An ideal technology would give you great performance in terms of bits delivered, but also allow you to reach devices that are subject to multipath and mobility. For me, this is a critical point, and one of a few fundamental requirements that must be included in a next-gen system: Broadcast airwaves need to be able to reach unattached devices.
More and more viewing is taking place on screens other than the fixed TV in the living room of your home. A recent Council for Research Excellence study1 has said that about 2 percent of all TV content viewing happens on mobile devices. That may be a small number, but it’s really just getting started, and it’s growing quickly. Still, one could debate whether a broadcast standard should reach such devices. I’m convinced that broadcast delivery (especially of live, high-demand content) is absolutely the most efficient, and therefore the most consumer friendly, way to deliver programming. It simply doesn’t make sense to me to replicate the same data over and over and use limited spectrum resources to deliver programming on a one-to-one basis.
But what if you don’t want to reach mobile devices and instead want to focus on delivering the most bits possible to a fixed antenna? A next-generation standard could allow for that case as well. Some of the most advanced broadcast standards today have modes that offer as much as double the bit capacity (somewhere around 40Mb/s) in the same channel.
That brings up another capability that should be part of a new standard: The standard could have multiple operational modes that are flexible enough to allow each broadcaster to optimize the delivery of bits based on how difficult the channel is or what their service model is. So if I want to be in the mobile broadcast business, I can. If the demand is for OTA delivery of 4K Ultra HD video at a very high bit rate, I can choose that instead. Or even better, I can deliver multiple services each with their own bit rates and levels of robustness all at the same time, and the device itself can figure out which service is best suited for its environment.
We know that the current ATSC system uses MPEG-2 for video compression. Over the past few years, codecs have advanced, and most newer video delivery systems are using tools from the MPEG-4 toolkit. That’s a technology that delivers approximately the same video quality at about half the bit rate. International standards groups are working on an even more advanced video compression standard called High Efficiency Video Coding (HEVC) that targets another 50 percent reduction in bit rate for the same quality. These advances in video coding are essential if you want to enable OTA delivery of higher resolutions such as 4K.
I can’t say whether 4K will be the next big thing in television viewing or whether it will go the way of 3-D, or perhaps be something in between. I do believe that many television viewers care about high-quality video, and as a broadcaster, I know I need to be prepared to deliver what my viewers want, and I don’t have that capability with today’s system. So it seems obvious that a next-generation standard would need to include the most advanced compression schemes available. Beyond that, the industry should look for a way that the system can evolve as compression technology continues to advance. What we really need is an upgradeable system that allows new, future codecs to be introduced without stranding receivers. This implies a system that allows receivers to be upgraded via software, a capability that many video playback devices already have.
Finally, a new standard could and should enable advanced services with the hope that these services will create value for users and enable new revenue streams for broadcasters and other participants.
The types of services envisioned — targeted advertising, synchronization with other applications (second screen or first screen), non-real-time delivery of content, etc. — have actually been talked about for a long time. Many of the ideas can be enabled by incorporating two things: a flexible data transport mechanism based on IP, and a flexible application execution environment on the receiver.
The good news for the broadcast industry is that television sets are already beginning to have those capabilities as part of Smart TV features, but we need to have a broadcast delivery that is able to take advantage of the features. Once the delivery and execution environment are set up, you have created fertile ground that will allow for creativity and flexibility in what advanced applications actually do. You don’t necessarily have to define exactly what all the applications are. That’s the vision that I believe our industry should have when it comes to a next-generation platform — one where we can innovate and evolve what we are doing.
One last point that overarches all these technical advancements is an idea that we need an “evolvable” standard so that we don’t end up in the same place again 20 years from now.
An evolvable standard is one where you can make changes as time goes on but not break existing services. It encompasses both forward and backward compatibility. You can choose to stay with an old version of the standard and still have devices both old and new continue to operate, or you can move to a newer feature set and not break existing receivers, albeit they may not be able to take advantage of the new features.
Much of the discussion among industry technical experts revolves around how to accomplish that. It sounds like an obvious idea, but it’s hard to come up with such a platform. The broadcast industry is hampered in two major areas where the telecommunication industry is not. First, we’re not vertically integrated. That is, we don’t control both the network and the user equipment. Second, we don’t have two-way communication with user equipment, so we can’t “negotiate” the communication link. Those challenges will be hard to overcome, but it will be important to do so if we want to make sure we don’t repeat history with a next-generation platform.
The next-generation broadcast platform that I hope to see will have all those characteristics: an advanced and highly flexible radio link that will allow me to deliver the maximum bits in challenging conditions; a video compression system that allows me to send the highest quality video that is available on the market; a platform that allows for new and innovation applications; and a defined path that allows for change so we’re not stuck with the same technologies forever. I’m happy that so many of my colleagues in the industry see this same possible future and are working together to make it happen.
—Brett Jenkins is VP CTO, LIN Media.