Comcast’s IP Transcoding Strategy Signals Appeal of a New Approach

Sam Blackman, chairman & CEO, Elemental Technologies

Sam Blackman, chairman & CEO, Elemental Technologies

August 1, 2011 – Comcast has taken another big step into the multi-screen service space with embrace of a next-generation transcoding platform for file-based content that has been winning customers with cost-efficient scalability performance built on high streaming densities and video quality.

Comcast says it is employing the file-based transcoding server supplied by Elemental Technologies for its Xfinity online and mobile service initiatives. At the same time Comcast’s video publishing subsidiary, thePlatform, has made Elemental part of its premier partner program, and both companies have agreed to market each other’s solutions to customers.

“Comcast is leveraging innovative new technologies that provide cost-effective performance enhancements as we bring more viewing choices to our customers online and on mobile devices,” says Charlie Herrin, senior vice president of product development and technology for Comcast Interactive Media. “Elemental has a highly reliable transcoding solution that, coupled with thePlatform’s cloud-based video management, is helping us deliver compelling services to our subscribers.”

As previously reported (July, p. 1), Comcast’s move to the next generation of Xfinity service, introduced in Augusta, Ga. and slated for wide rollout in the months ahead, includes a transition to an all-IP cloud-based backend running on thePlatform’s mpx content management system. This sets the stage for migrating legacy TV content to IP as well as expanding the flow of native IP content into the Xfinity online and mobile outlets.

From an encoding standpoint, the first step in the IP migration is to establish a means of transcoding all the files positioned for on-demand distribution to subscribers’ PCs, tablets and handhelds. Each program or movie is stored as a single file and transcoded to suit the format of viewers’ devices, including bit rate, screen resolution and adaptive streaming mode. Adaptive streaming formats supported by Elemental include Apple HTTP Live Streaming, Microsoft Smooth and Adobe Dynamic Streaming.

“XfinityTV.com is a Flash-based Web site which initially is supporting distribution to iPhones, iPads and iTouch [iPod touch media player],” says Sam Blackman, chairman and CEO of Elemental. “But we’ll likely be scaling to support Android and other platforms Comcast rolls out over time.” The Elemental Server is creating 18 adaptive streaming outputs matched to various device templates for every incoming asset, he adds.

While there are thousands of hours of content ingested into Xfinity from Comcast’s programming partners each month, this is just the tip of the iceberg when it comes to all the content the MSO might eventually make available over the IP on-demand distribution platform, Blackman notes. “There are many more assets they want to offer over time from their archives,” he says. “Enormous libraries of content will need to be processed beyond what’s coming in daily to the Xfinity group.”

Elemental hopes to do well enough on fulfillment of its initial contract to win this business as well, he adds. “This is just the beginning of what we hope will be a tremendous relationship with Comcast,” he says.

For a company that released its first product for general commercial availability just a little over one year ago that’s a pretty ambitious goal, given the welter of long-established players in encoding and transcoding that are competing for the same business. But it appears Elemental is making a convincing case for its claims elsewhere as well, having won, for example, the transcoding business for the recently launched ABC News iPad app, which supports access to text and video from the network’s archives and current reports.

A major goal in ABC’s deployment of the Elemental Server was to expedite the transcode portion of the overall workflow in order to reduce the lag time between the availability of content on ABC.com and the availability of the same content via the iPad. Officials say the server allows ABC to convert more than 20 640×360 or 480×360 files in real time for on-demand adaptive streaming over the Akamai streaming media service used by ABC. In keeping with the “chunking” parameters of Apple’s HLS, the files are incremented in ten-second segments for output at five different bit rates ranging from 64 kilobits per second to 700 kbps.

“We have other Disney portfolio customers that we can’t announce,” Blackman says.

Other announced customers in the U.S. include Avail TVN, Big Ten Networks, CBS Interactive, National Geographic, News Press & Gazette, PBS and Oceanic Time Warner Cable. With a European office just opened in London during the second quarter, the company has announced TF-1 France, WRN Broadcast UK, QVC Italy and VMMA in Belgium as its first customers there.

As described by Blackman, Elemental Server is a Linux-based software system designed to run on both GPUs (graphics processing units) and CPUs. CPUs are the processing cores most used by software-based encoding and transcoding systems. Employing GPUs with up to 512 highly programmable core processors running on a massively parallel architecture to perform the most complex video compression tasks allows the Elemental Server to execute transcoding at much higher speeds and greater densities than is usually the case, Blackman says.

“For the core image compressions and decompression we use a combination of GPU and CPU processors, allocating resources to whichever platform is best suited to a particular task,” he explains. “A lot of the secret sauce in our technology is how we divide those functions. GPUs are incredibly fast for image processing.”

GPU functions include scaling, interlacing and all the pieces required to create adaptive multi-screen formats, plus some aspects of the encoding process, such as motion estimation, de-blocking, inverse quantization and other tasks that run across massive numbers of pixels on each frame. Other tasks involving processing of bit streams one at a time, such as entropy encoding and syntax encoding, are best suited to the CPUs.

“We sell the technology either as a complete solution in an appliance or as software that people can run on off-the-shelf Intel servers that include NVIDIA GPUs,” Blackman says. “Either way there’s no need for specialized hardware.”

Elemental has taken the extra step of building all the image processing and compression codecs supporting H.264, V-1 and MPEG-2 from the ground up as a way to maximize these processing efficiencies, he adds. “This offers dramatic benefits to our customers, not only in performance but also because, if they find problems, we can turn around and fix them immediately, rather than requiring people to wait weeks or months for third parties to deliver the patches,” he says.

While the solution adds about 20 percent to the server costs compared to a system running on a CPU-only server, the higher streaming density of the Elemental system results in significant savings when scaling to large libraries is involved, Blackman says. “In the case of Comcast, when they moved from a competitor to our platform, they reduced the physical footprint by 75 percent,” he says. “Our product requires one quarter of the space, so customers end up saving a lot of money in cap ex.”

A recent comparative study of encoding and transcoding solutions produced by Transitions, Inc., a research firm headed by StreamingMedia contributing editor Tim Siglin, appears to bear out some of Blackman’s claims. The study tested workflows, processing speeds and quality on industrial-strength file-based transcoding and live encoding systems from about a dozen leading suppliers, including hardware-based as well as software-based platforms. Participants were given the option to avoid having their individual results published and compared to the industry averages.

Elemental was the only participant that allowed its results on the extensive series of tests to be published publicly, Siglin notes. In a variety of tests involving 32 source files that were transcoded sequentially and at various levels of simultaneous treatment on a single and on multiple nodes Elemental Server performed at far faster speeds than the average of all participants with overall quality performance on par with the average, Siglin says.

“Elemental produces very fast and robust systems,” Siglin writes in his report. “When one reviews a fast system, the immediate reaction – as stated succinctly by another participant – is that the laws of physics apply.

“In other words, it often seems one can’t have both speed and quality. Yet, given the GPU-centric approach that Elemental uses, it appears that the company is able to generate quality outputs at significantly faster-than-average speeds, generating good marks in both performance and quality.”