Video Quantity and Quality: Balancing Both can be a Delicate Operation.

Consumers would like more of both, if you please.

Consumers are hunkering down to weather the economic downturn with a slice of take-out pizza in one hand and a remote in the other. A promise of more content at a better triple-play package price could sway them just as easily as a restaurant coupon offering three toppings for the price of one.

A number of digital video service providers — Verizon, AT&T, Time Warner, Cablevision, DirecTV, etc. — have reached the 100 high-definition (HD) channel hurdle. Comcast, which measures the total linear and on-demand HD "choices" it offers subscribers, touts more than 1,000 in some markets.

Each of these providers faces additional competition in the HD market. For its part, Netflix offers more than 2,000 Blu-ray DVDs on its online portal. So the quest for more continues.

Assisted by their technology partners, multi-system operators (MSOs) are especially keen to surpass spectral and other constraints and exploit the efficiencies of digital video, all the while maintaining, if not improving, the quality of experiencing video in their lineups.

More QAM, less dough

One trend is to move from a broadcast to a multicast or switched unicast model, where programs are delivered only when requested. This has been the approach of Time Warner and Cablevision. "This shift alone is going to be a major help in terms of access network bandwidth in the core," Jeff Heynen, directing analyst, broadband and video, Infonetics Research, said.

More routers and switches are needed to deliver the multicast channels to their end points. It also requires the expanded use of quadrature amplitude modulation (QAM) technology. "You need more Edge QAMs (EQAM modulators) and more QAM (channels) out in the field because everything is on demand," Heynen said.

Even analog reclamation, the approach that Comcast has aggressively adopted, calls for more QAM technology. Spectrum that once carried analog signals does not spontaneously erupt with digital content. It calls for digital modulation.

Some are tackling this challenge at the component level. A denser chip, for instance, is one way to get QAM channels at a lower cost. With 16- and 32- channel versions, BroadLogic’s TeraQAM BL85000 promises up to four times more QAM channels per port.

"Four chips generate the entire spectrum or 128 QAM (channels). Four TeraQAMs could generate all the QAMs needed by the homes at the node level," Daniel Faizullabhoy, BroadLogic’s president and CEO, said. The company has pushed the cost below $100 per QAM and reduced power consumption and size.

"Everyone has started to question where is the edge of the network today. Now you can put it where you want — closer to the subscriber," said Al Johnson, vice president of marketing, BroadLogic.

VOD in a Flash

In the on-demand world, operators have mirrored on their digital video platform the content delivery network (CDN) architecture used by the Internet.

When a request for content is made from a website like ESPN, the closer it is stored to the user, the faster the response time and the easier it is to scale.

"(This) gives ESPN the ability to reach millions of users if not everyone is coming back to talk to one server complex," Tom Rosenstein, vice president, marketing, Verivue, said.

In cable’s on-demand world, it doesn’t make economical sense to put separate copies of all content at every headend. "In reality, we all watch the same content. Out of 15,000 hours of content, 12,000 are rarely accessed. In a CDN model, less popular content is deep in the network," Rosenstein said.

The distributed model is nothing new. What is relatively new is the server technology that has surfaced as an accelerator of on-demand video content to the edge of this network.

Storage technology has shifted into an accelerating transition pattern in recent years. Dynamic random access memory (D-RAM) technology made its debut into an on-demand arena dominated by electro-mechanical (moving disk)-based technology courtesy of Broadbus Technologies, a startup that Motorola acquired in 2006. In the following year, SeaChange and then Concurrent each introduced servers using Flash memory — like D-RAM, a solid-state technology — to use at the network edge for caching and streaming the most popular content.

In early 2009, ARRIS and Comcast-backed Verivue and the Swedish company Edgeware both turned up the marketing volume on their Flash-based products. Motorola launched a mini server, the B-3, which also uses Flash. The technology benefits are compelling.

According to SeaChange, by incorporating the company’s MediaServer Flash Memory Streamer into its architecture, Buckeye CableSystem was able to add 7,000 streams to its VOD capacity. "Flash systems offer higher performance in peak capacity…They are incredibly reliable with no spinning disks," Howard Rubin, senior product marketing manager, SeaChange, said.

"(Cable operators) can put servers anywhere they want. If they have a backbone with limitations because it originally was intended for broadcast TV then they can still deploy a large on demand service by putting servers farther in the network," Edgeware CEO Joachim Roos, said.

The flash-memory servers also consume less power, use less rack space, and don’t need the same type of redundancy schemes as their predecessors. Edgeware says its Orbit 2x video servers store 6 TB of data, produce a guaranteed output of 20 Gbps and can ingest data at a rate of 1.2 Gbps. The cost is about $25 per stream, Roos said.

Asset propagation systems shift content based on local popularity. "In each server anywhere in the network it creates a local view of the popularity curve containing all assets…if a new asset becomes more popular than the least in storage, the servers swap out the now (less) popular asset and replace it," Roos said.

Verivue’s MDX 9200 incorporates an Ethernet switch into a 14RU box with the storage and delivery mechanism and can handle multiple protocols, a key consideration as service providers move inexorably toward a multi-screen world.

"The operator doesn’t know where people will watch TV next year…They can put this in today, respond to today’s needs and meet tomorrow’s," Rosenstein said.

DVR possibilities

Sitting at the edge and with sufficient ingest performance, flash-memory servers could also facilitate time-shifted television and remote-storage DVRs, where consumer recorded content is stored in the network and not in the set-top box.

"The challenge PC-based systems have is they can’t record content into themselves fast enough…We can save 1,800 channels simultaneously and record them into the system," Rosenstein said.

The concept of RS-DVRs hit a snag when content providers said it led to copyright infringement, but the 2nd U.S. Court of Appeals sided with cable operator Cablevision. In May, the U.S.wwwq Department of Justice issued a memo recommending that the Supreme Court not re-hear the case. In June, the Supreme Court agreed.

In the meantime and in any case, however, Cablevision had signaled its intention to relaunch its RS-DVR service this summer.

The benefits could be great. "A subscriber can record only so much with a DVR at home. (With RS-DVR) the cost goes down and they have access to more content," Zippy Aima, industry analyst, digital media, ABI Research, said.

More efficiency

Yet, all of this boils back down to needing spectrum, or more efficient use of it.

The uptake rate for time-shifted TV alone has been shown to be 70 percent with 40-50 percent of those subscribers using it at any given time.

"You need the bandwidth to handle the VOD session and set it up at a moment’s notice…If you developed a network for 10,000 streams you probably have to go to a lot more than that," SeaChange’s Rubin said.

"The operator doesn’t know where people will watch TV next year." Tom Rosenstein, Verivue

A number of companies offer solutions that compress more than two HD streams into a 256 QAM channel. Harmonic is up to four, filtering out errant bits, and modeling the human eye to limit loss distortion.

"We have dramatically increased the amount of processing power through intelligent architecture (and) applied the processing power in more effective ways," David Price, vice president, marketing and communications, Harmonic, said.

On the VOD side, RGB’s Dynamic Bandwidth Manager converts VOD streams to variable bit rate and stat muxes them so that 15 SD streams or 3 HD streams fit into a QAM channel instead of 10 SD or 2 HD.

"The amount of savings on a per QAM basis allows operators to add an HD stream to each QAM serving SD today without changing the architecture," Ramin Farassat, vice president, marketing, RGB, said.

Quality concerns

An operator can squeeze as much into a QAM as it likes, but if quality suffers, consumers will notice on their sensitive big screen TVs, Heynen said. "There are always tradeoffs in anything you do whenever you are trying to multiplex."

The same goes for converting VOD streams to VBR. "Some operators say when you move to VBR you do sacrifice quality, and they are unwilling to take that step," Heynen said.

Monitoring quality overall becomes more challenging the more complex the operator’s world becomes. "Historically VOD was on its own network so VOD and normal programming didn’t mess with each other, couldn’t damage each other. Now they are all piled on the same network because of smart devices," Eric Conley, Mixed Signals, CEO, said. (For more on companies in the video quality space, see sidebar.)

In addition, a quality assurance solution should address multi-vendor environments, Asha Kalyur, senior marketing manager, Cisco, said. "Flexibility would recognize the addition of last-mile drop points to support new subscribers, understand software upgrades in switches and routers and accommodate new bandwidth-management schemes over time."

Squeezing more out of bandwidth requires better quality monitoring, but monitoring tools can help with bandwidth efficiency. By trending channel behavior, an operator can run simulations.

"They can try out different optimizations of channels through the existing infrastructure without actually doing it in production," Conley said. "They can find where they’ve got room and add channels that won’t overload the infrastructure."

However operators optimize their infrastructure and lineups, the message from the viewer nonetheless remains consistent, even insistent: More video, if you please, but don’t you dare sacrifice quality.

Monta Hernon is a contributor to Communications Technology.

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