High-definition TV has become the latest flashpoint between cable, satellite and telco providers,
which means cable needs to keep adding HD channels to keep pace. Some of the bandwidth tools in
the toolbox include switched digital video, better compression and encoding, and, eventually, MPEG-4.

It’s a mad, mad, mad HD world out there, and it only figures to get even crazier this year with MSOs, telcos and satellite companies all aiming to fill their channel lineups with more and more HD channels.

From the consumer end, the prices of HDTV sets have gone down, which means millions of HDTVs will continue to fly off the shelves this year, even though some of those consumers won’t have those new sets hooked up to true HD services. Jupiter Research predicts that 78 percent of U.S. households will have HDTVs by 2011, which will only increase the clamor for more HD channels, making the need for more bandwidth that much more acute.

“The fact is that they’re (HDTV sets) within virtually everyone’s reach now, and a flat panel TV is no longer a luxury item,” said Bryan McGuirk, SES Americom’s president of the media and enterprise division. “You can get a 42-inch HDTV for under $800 now and there were something like 5 million HDTV sets sold last year. We’re extremely bullish on HD.”

Now that consumers are armed with HDTVs in their living rooms and dens, they’re ready to look at what provider has the best lineup of HD channels. We can all thank DirecTV for indirectly pushing the HD liftoff button last year when it said it would have 100 HD channels by the close of 2007.

Never mind that DirecTV actually finished last year with closer to 86 HD channels, or 71 if you don’t count multiple east and west coast feeds and regional sports channels that aren’t available to every subscriber; the HD gauntlet has been thrown down with cable, telco and satellite providers fully engaged in toe-to-toe HD bragging rights.

A quick tally of the HD lineups has Dish Network in second with 70 HD channels, followed by Cablevision and Rogers Cable with 45 and 40, respectively. But that’s all about to change as the various competitors vow to win the hearts and wallets of consumers with even more HD offerings this year.

On the telco side, AT&T has more than 40 HD channels in most of its markets after eight HD channels were added near the end of last year. AT&T isn’t saying what its target is for HD channels this year other than the HD lineup “will expand significantly this year,” in addition to another HD stream. Verizon has said it expects to have 150 HD channels by the end of this year, up from its current roster of 30.

Pragash Pillai

Leaving aside HD VOD for now, how will cable make room for the additional HD channels it plans to add this year? There are various tools in the toolbox, including switched digital video and node splits, MPEG-4, plant upgrades, going all digital and better compression and encoding techniques, but there isn’t a one-size-fits all template.

“I think cable operators are looking at the trend of people saying they want more HD, but on the other hand, do we want every channel out there on HD, or do we want to put on channels that are relevant to our customers?,” said Pragash Pillai, Bresnan Communications’ vice president of strategic planning. “Our target is to have 50 distinct linear HD channels by the end of the year, and add some HD VOD content as well.

“I think the important thing is that every operator needs to look at each market and address it appropriately. Based on feedback and ratings, we’re going to look at what our customers really want and that’s what we’re going to put on there instead of just launching HD channels.”

Currently, Bresnan offers 16 to 20 HD channels in its various markets, but Pillai said the goal of 50 can be met this year with the current amount of bandwidth that Bresnan has available because it has about 65 analog channels instead of the 70 or 80 analog channels that are typically found on most cable operators’ lineups. Speaking at the SCTE Conference on Emerging Technologies, Pillai said Bresnan will start looking at bandwidth-expanding options, such as switched digital video, sometime next year.

Rogers was ahead of the curve when it came to launching HD channels in 2001. The company’s plant was in good shape because it had gone all digital in 1998 and had HD in mind when it upgraded its HFC plant.

“We first launched with eight HD channels, which at that time was the most in Canada and maybe the most in North America,” said Tony Faccia, Roger’s vice president of networks and capacity planning. “Since that time we’ve recognized the need to offer as many HD channels as we can.”

While Rogers doesn’t compete with an IPTV provider just yet, it does compete with satellite provider BellExpressVu for video customers. BellExpressVu, like the satellite providers in the United States, has made the number of HD channels a selling point since it can’t compete in the VOD arena.

“We currently have 40 HD channels, but we can also include some sports HD channels when we have the content,” Faccia said. “If there are different sporting events then we broadcast to all of the HD muxes, which brings us to about 48 channels.”

Rogers launched several HD channels last year and plans on additional offerings over the next few years as it moves toward the all-digital deadline of 2011 in Canada. What has helped Rogers meet the demands of adding more HD channels to date is that 85 percent of its homes passed are on 860 MHz plants, while 94 percent of all of its plants are at least 750 MHz.

“We have a lot of spectrum that helped us launch HD and we have a program in place to upgrade the rural remote areas up to 860 MHz, “ Faccia said. “We were also helped by the ability to launch all of our digital muxes at 256 QAM, and another approach we took was migrating our analog services.

“Those have helped us get to where we are today, but looking forward we’ll be doing a field trial of switched digital video in a couple of months and after that we’ll select our vendors to roll out switched digital video this year in most of our areas.”

Aside from switched digital video (SDV), Rogers contemplated a plant upgrade to 1 GHz, but that was discounted due to the high cost and because the legacy set-top boxes can’t operate above 860 MHz.

“We also looked at 1024 QAM and we’ve done some testing, but for the amount of bandwidth we gain to launch new services in the mux there’s a significant amount of susceptibility to noise,” Faccia said.

ICE broadcast system 3:1 HD - Click to Enlarge
Imagine Communications and the Comcast Media Center are able to get three
HD channels in one QAM by using real-time second pass encoding.

Among the tools in the cable operators’ toolbox for enabling more bandwidth, SDV is the one that operators will have in hand a lot over the course of the next few years.

Switched digital video has been around since 2004 when the first trial took place in Austin with BigBand Networks and Time Warner Cable. Switched digital video sends just the programming that people in a service group or node are watching instead of the entire slate of channels, and while the technology also holds promise for sharing bandwidth resources between video silos such as VOD and SDV, SDV’s big impact this year is reclaiming bandwidth in order to allow MSOs to deploy more HD channels.

Cable operators can typically garner a 2:1 reclamation of bandwidth by using SDV. Biren Sood, BigBand Networks’ vice president and manager of cable video, said operators are approaching 4:1 oversubscription with SD programming, but also with combined SD/HD lineups.

“In late 2006 we started seeing one or two operators actively switching HD,” Sood said. “At the end of last year and into this year we expect to see double digits (of systems) switch HD. We have one operator who is switching more than 20 HD services in the switched tier. Switched is more operationalized and we have deeper insight now, so we expect to see more HD services in the switched tier.”

Comcast Media Center
The Comcast Media Center is working on
various technologies to help cable operators offer
more HD programming, including its 3:1 QAM solution.

Greg Hardy, Scientific Atlanta’s vice president of video development, said switching HD channels, instead of the long tail content that was previously typical in SDV deployments, would be big for cable operators over the next few years.

Speaking at a session at Paul Kagan’s “QAM Before the Storm” event in Los Angeles last month, Hardy said of SDV, “It’s not just recovering bandwidth, but delivering HD.”

Hardy said that while SDV was a great technology, cable operators need to be aware of the size of the service groups where channels are being switched. MSOs can add more QAMs, but Hardy said the best bang for the buck was doing node splits. Service groups that are too small provide diminishing returns if most of the people in that service group are watching the same channel.

Arris’ Charles Cheevers, CTO, Europe, speaking at the Kagan conference, predicted that by 2015 there would be 61 channels mapping in and out of SDV once DOCSIS 3.0 is fully mature, and that unicast will be deployed in an on-demand mode.

Wherever there’s a void in technology, vendors are sure to rush in. While MPEG-4 is on the horizon, cable operators and vendors are still breathing new life into MPEG-2. One example is the Comcast Media Center’s three HD channels in one QAM solution that the CMC developed in conjunction with Imagine Communications.

Imagine’s Marc Tayer, senior vice president marketing and business development, said while Imagine still sees its technology being used for SDV and VOD, it focused its first product release last month on giving cable operators up to 50 percent more bandwidth for HD and SD broadcast signals.

“If you look at our technology and what it can do for cable, it can certainly help expand VOD and SDV, which are still relatively small services in terms of the capacity of the cable system they use,” Tayer said. “Whereas if you look at digital broadcast, and HD broadcast expansion, it’s by far much larger than the bandwidth occupied by SDV and VOD. In terms of leverage, we can save cable a lot more overall bandwidth by addressing the digital broadcast issue first, without by any means taking our eyes off the ball on SDV and VOD.”

Gary Traver

Imagine took its video processing and multiplexing technology, which relies on variable bit rates instead of constant bit rates, to the Comcast Media Center to come up with a real-time second pass encoding system that allows the CMC to mix three different categories of HD channels, such as one sports program and two talking head shows, onto one QAM.

CMC COO and senior vice president Gary Traver said the goal was to not only find a way to save bandwidth, but also to keep the quality as good or better than the competitors’.

“The first thing we’ve done is we’re using techniques of second pass encoding, which were really developed for doing digital encoding for movie studios,” Traver said. “What happens is that you encode something and then see ways to improve on it. Then you go back into the encoding methodology and do alterations of it. If you look at the product Imagine has come up with, which we worked closely with them to develop, it’s doing real-time second pass encoding. We take content that was originally created in an MPEG-2 format and then we evaluate the way the product was encoded, and then we provide some techniques to optimize it.”

Traver said the CMC goes into the core of an MPEG -2 signal that was created by the programmer and enhances it, which is different from the techniques that cable operators have traditionally used.

“They go in and physically rate shape something, and by rate shaping what they’re doing is coming in at one bit rate,” Traver said. “They’re literally going in through relative standard techniques and just adjusting the bit rate downward. That’s not what second pass encoding is doing. It’s actually going through optimizing the encoding in a very different way than a rate shaper would.”

The CMC also focused on what consumers see on their TVs instead of relying on a “Golden Eye” system – relying on expert viewers. The CMC has an HD viewing lab in its building outside of Denver, where consumers were marched through to see if they could find any differences in the pictures on various TVs.

“There are a couple of things that we did that we thought were extremely important,” Traver said. “The first was understanding what could be done on the front end before the signal ever gets to us. That would make it easier to preserve the quality as we’re carrying the signal through.

“The second one was really focusing in on not what engineers were reacting to, but what consumers were reacting to. That sounds like it would be a no-brainer, but in many cases, it’s really very new and very different. A lot of the Golden Eyes that study compression are engineering trained and they have a slightly different bias than consumers do. Our initial conclusion is they’re not completely aligned.”

The CMC is taking the HD from the second pass encoding and putting it on new satellites through a recent deal with SES Americom. CMC is consolidating its HITS platform onto three satellites that are two degrees apart instead of the seven that were previously used. The close proximity of the satellites will allow the entire HITS Quantum and HD Quantum lineups to be picked up by one triple-beam antenna.

The CMC will also move its services from Ku-Band to C-Band as part of the overhaul. Traver said C-Band will provide more availability because it’s not subject to the rain fade of Ku-Band.

SES Americom’s McGuirk said his company currently has 34 MPEG-2 HD channels and 30 MPEG-4 HD channels but he expects to see 63 more HD channels launching by the end of the year.

While MPEG-4 does save bandwidth by providing a 50 percent bit rate reduction in compression over MPEG-2, there are too many MPEG-2-based set-top boxes deployed by cable operators for a wholesale change this year.

While large-scale deployments of MPEG-4 boxes are at least several years out, Bresnan’s Pillai said his company will be ordering hybrid boxes this year whenever they’re available.

One way of transitioning customers over to MPEG-4 set-top boxes is to set up a premium tier for customers who are willing to pay for the new boxes. Rogers’ Faccia said his company is looking at launching a premium sports package and some premium channels in MPEG-4.

Thanks to cable networks such as HBO, MPEG-4 is coming, and cable operators need to be formulating their transition plans now.

“MPEG-4 will bring a lot of new challenges in terms of being able to do everything that was perfect on MPEG-2,” said Keith Rothschild, Harmonic’s senior manager, cable strategy. “There are things that need to be tweaked in order to do them on MPEG-4; all the ad insertion, the rate shapers, and some of the VOD servers.

“I think we’ll need to see a critical mass of MPEG-4 capable consumer devices before the operators put a significant amount of content out, because in order to compete against satellite, they need to offer the majority of their customers HD content right now.”

Cable operators will be on a continuing quest to add more bandwidth as they bring in new services and new technologies. While some techniques ease bandwidth constraints, others actually increase capacity, such as Vyyo’s spectrum overlay. Vyyo’s spectrum overlay uses higher frequencies on the existing coaxial cable, doubling downstream bandwidth and increasing upstream bandwidth by a factor of at least four.

“If you took 650 MHz downstream by about 6 bits per hertz, it’s around 4,000 megabits per second,” said Vyyo CTO Dave Feldman. “Each HD service takes 12 to 15 Mbps, so that’s between 200-300 simultaneous HD channels. That’s a pretty large number compared to what is typically out there.”

The analog to digital reclamation that some cable operators are undertaking is also a good way to free up channel-locked bandwidth.

“We think that with the cost of set-top boxes now coming down, the opportunities that are gained by converting to an all-digital network are real,” CMC’s Traver said. “We think that’s a big deal, especially for the small to mid-size markets where cable operators haven’t kept up with some of the plant upgrades. They’re sitting at 450 MHz or 550 MHz, so they really need to find ways to improve their bandwidth in order to get to the HD channels they need.”