A press release from Path 1 Networks recently crossed the desk of HD Technology Update discussing a demonstration of HD transmission via IP at Texas A&M University in College Station, TX.
The application, while interesting, involved Internet 2, a super-high bandwidth next generation Internet that’s currently the province of educational institutions and the government.
However, the application, which also involved an HD upgrade to distance learning between the university and Qatar for U.S. troops, was relevant in the broader sense to broadcasters because it demonstrated the viability of using IP circuits to transmit high definition content — something that increasingly touches television operations like contribution and program distribution.
HD Technology Update caught up with Path 1 Networks vice president of marketing Rick Segil while on the road to learn more about the Texas A&M application and the broader role of HD transmission via the Internet.
HD Technology Update: Texas A&M University is delivering distance learning applications via Internet 2 between the United States and Qatar. What is the relevancy of Internet 2 for my readers given it is currently a broadband network for the government and universities?
Rick Segil: Two part answer: First of all, Texas A&M is a local PBS affiliate, and what they are doing is broadening the awareness of high-definition TV over IP circuits in general. So they initially started off with this demonstration that the press release highlighted. This demo used the Internet 2 and a wireless last mile to a local outdoor venue where they had a big screen presentation of high definition. The audience was users, technicians and administrators who are involved with the Trans-Texas Videoconference Network. And what they were able to demonstrate was that high definition over IP is alive and well. It is something the rest of the state might want to be considering for high-definition programming exchange and even more importantly, that it can use a hybrid network of I-2 and wireless connection in order to really drive the point at how robust Path 1 technology is.
Secondly, focusing on what the Qatar link is, Texas A&M University is currently providing distance learning education for the troops that are over there. They wanted to augment the caliber of the programs that were being sent over to Qatar. So that’s where the high definition upgrade of that existing service offering is focused. That particular high definition link is not over the Internet 2 the entire way. It was a hybrid link, once again partially I-2. The connection from College Station was via Abilene to MANLAN in New York City and then via dedicated Atlantic and Pacific 155Mb/s links to Education City in Doha, Qatar
I think what’s interesting here and specific to Texas A&M is that they needed the equipment to solve a demonstration problem in particular and then are applying the technology in a couple of different ways going forward. They’re still fine-tuning exactly what that service offering will be. We thought it was interesting that they were able to do the hybrid link, and the fact that they’re raising the overall awareness of high definition over IP, let alone video over IP, is something we wanted to highlight. And I guess the third point is to the extent that the public Internet or non-private line connections are being used.
HDTU: Using the public Internet raises a whole set of issues in terms of quality of service doesn’t it?
RS: The way we look at this issue is to make parallels with voice over IP. VoIP was used for long distance traffic several years before people like Vonage showed up and started using voice over the Internet. So, we believe a similar situation is developing in the video marketplace today in which video over IP has been used for several years, and the innovators are exploring video over the Internet. Vyvx has been using our equipment for the HD VenueNet for several years and what we are looking to enable customers that take video over the public Internet.
We have right now a couple handfuls of customers who are doing exactly that. One of our links goes all the way from Hong Kong to London over three different public Internet service providers and they deliver perfect video to a satellite uplink over that 13,000mi length. So if you are worried about your network, what we provide is an intelligent gateway that takes the network anomalies out. Some of the most recent capabilities we’ve put into our product allow you to characterize and monitor the quality of your link to make sure the forward error correction settings are robust enough to ensure perfect video at the end. That’s our unique capability.
HDTU: Some of the large broadcast networks have been using this technology for backhaul of important sporting events like the Final Four and the Super Bowl. In these settings, there’s no tolerance for loss of programming. So, video sent via IP over the Internet is typically used in parallel with satellite transmission for backhaul. Will the industry get to the point that satellite transmission will wither and fade away as video via IP takes over?
RS: Absolutely. I think it is going to happen faster than people realize. Actually, it’s my understanding that the primary and secondary feeds for the past two Super Bowls were using the IP backbone and our products. So I think the transition is already being made from being a secondary feed to being the primary feed on a lot of these sporting events.
HDTU: Discuss the issues of reliability and quality of service for the application of IP transport of video in a broadcast environment. Specifically, could you address the role of FEC, clock synchronization, and buffer control in maintaining quality?
RS: Path 1 prides itself in the overall product solution we’ve been able to bring together. The broadcast industry has some very tight tolerances with regard to line timing and overall signal quality. And if a data network is simply asked to carry video packets, you’re going to run into problems. We don’t care how good the network is. The need for forward error correction to anticipate either out of sequence packets or a router getting saturated is essential in order to maintain perfect video quality for a broadcast type environment. That’s the kind of thing we specialize in.
You could spend a lot of time and money making your networks as good as possible and we believe they’re still going to be a little bit less than you expect. Our solution makes the gateways robust and powerful to monitor the network, to collect the statistics, to characterize the sort of problems the network is encountering and then be able to implement the right kind of forward error correction for that particular transmission.
We have a set of software tools that enable us to diagnose in advance of even putting live traffic on net so it can characterize what we think that network is capable of doing in terms of moving video with forward error correction. And our latest software release, the Vx8000 version 3 has a lot of those same monitoring tools built into the actual gateway. With real-time link monitoring, anyone can ensure enough forward error correction for perfect video. So with proper provisioning, we believe you can have Path 1 solve the challenges of transporting video over any IP network. Now, I’m sure someone will come up with trying to move 5Mb/s down a 2Mb/s pipe. We can’t exactly solve that problem, but within a realistic type situation, we generally overcome every network anomaly problem.
HDTU: In the A&M application, they were transmitting at 14Mb/s via a Path 1 gateway. Will that rate be sufficient for broadcast backhaul and contribution of programming?
RS: Well, we know the FCC standard is 19Mb/s and change. And what we are finding is a lot of broadcasters are doing it at 14Mb/s, even though the FCC specified channel is 19Mb/s. As far as with the current grade of video compression quality that’s coming out of the MPEG-2 high-definition encoder, 14Mbs seems to be where some of the major programmers are standardizing.
Choosing a 14Mb/s transmission rate is more of a programmer’s decision and the quality that their encoder is capable of delivering, and we are seeing some great quality at that level.
HDTU: What will MPEG-4 H.264 do to this whole equation? RS: As that encoding technology matures, people talk of a 50 percent type of reduction in the overall bit rate relative to MPEG-2. I think that 50 percent bit rate in some respects is calibrated against the 19.4Mb/s ATSC standard, so that means the high-definition broadcast might be down around 10Mb/s. So, some of the enhancements that the MPEG-2 encoders have been able to do is to get to 14Mb/s. With MPEG-4, maybe there is another 30 percent reduction that might occur in that overall bit rate to be in the 8- to 10Mb/s range as it matures over time.
HDTU: Could you discuss your ClearPath FEC technology and its role, specifically how it’s optimized to operate in a real-time HD transport application, such as the one A&M used?
RS: The ClearPath technology first of all embraces the Pro-MPEG COP #3 forward error correction standard. So we are fully complying with the standard and there’s been various interoperability tests between different manufactures of Pro-MPEG COP #3 forward error correction to make sure we have a standard that is truly an interoperable standard.
In addition to that we’ve taken the benefit of some of the intrinsic hardware capabilities that our gateway incorporates and we’ve enhanced the Pro-MPEG capabilities with something we call ClearPath Pro. What ClearPath Pro brings to the equation is the ability to accommodate longer burst outages and be more resilient to the challenges of the public Internet. In our estimation, COP #3 is very good for some of these private line networks, but when you start talking about the public Internet, the extra level of FEC protection ClearPath Pro provides is essential. Essentially ClearPath Pro is an extension to COP #3 that adds a greater tolerance for burst errors.
HDTU: Could you discuss ClearPath in terms of the A&M application?
RS: I believe Texas A&M ran into a network transition problem when going from the Internet 2 to the microwave link that the hand off and the equipment that was utilized was generating a fair amount of burst traffic loss. What they were able to do was utilize ClearPath Pro forward error correction such that when the burst errors occurred, we could essentially ride through the storm – real time.
Instead of trying to improve the quality of the link or get a different microwave vendor, they simply made do with what they had by provisioning at nodes of the network as opposed to trying to figure out “What’s wrong in my network?”
“Let’s just simply put in a gateway device that solves the network anomalies.”
HDTU: What is the latency involved in an application like this?
RS: The latency has everything to do with the video bit rate and overall network quality. Latency becomes a function of what sort of burst outage you want to be able to survive. Latency could be anywhere from essentially non-existent to up to several seconds if you wanted to take full advantage of the capabilities of ClearPath Pro. Over some really noisy networks, ClearPath would be able to solve – again depending on the bit rate- up to a couple of seconds’ worth of video outage.
Tell us what you think! HDTU invites response from our readers. Please submit your comments to firstname.lastname@example.org. We'll follow up with your comments in an upcoming issue.
Back to the top