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Technical problems bug Internet TV design

Posted: 20 Jul 2007 ?? ?Print Version ?Bookmark and Share

Keywords:Internet TV? technical problems? design bug?

Computer, STB and Web companies share a vision of a system that brings to consumers, in an easy-to-use way, the benefits of video on the Web. But thorny technical problems that range from silicon to software hamper efforts to design successful Internet TVs.

The Web lacks the QoS expected for TV viewing. It spawns a rapidly changing array of codecs and rights-management schemes. What's more, there are no dedicated chipsets, applications software or open Web video portals to guide an iTV system.

Nevertheless, many designers hold fast to a belief that the Internet will be the future of TV. Detractors say big cable and telephone carriersnot Web TV wannabeswill define the future of TV.

"Networked TVs are coming, and all CE guys will eventually make them," said Leonard Tsai, a senior consumer systems engineer at Hewlett-Packard Co., speaking at the Internet Television Technology Conference in the United States this week. Nevertheless, he said there are currently many uncontrolled variables that make networked TVs hard to develop, and these devices are not yet capable of providing quality user experience.

"Internet TV is probably going to outstrip telco TV eventually," added Paul Fellows, another presenter and chief technology officer for England's Amino Technologies plc, which makes set tops for telephone companies providing TV service. "The lack of a quality-of-service standard is probably the biggest problem we have," said Fellows.

Closed telco networks can get packets delivered predictably with latencies of 300ms, a fact that lets them squeeze memory buffers in their set tops to tiny proportions. By contrast, the Internet TV set top Amino designed uses buffers that handle up to 5s of video, a maximum users find acceptable, he said.

Need for open standard
Engineers also need an open standard for how they can find video on the Internet.

"There seems to be a myriad of ways of embedding video into a Webpage. I am sure every programmer just makes up their own way," said Fellows. "If we could get an HTML standard for embedding video on a Webpagethat would be super, especially if it includes a text description of the video," he added.

Another major hurdle is developing a box that is low cost yet powerful and flexible enough to support an ever-changing array of codecs and digital rights management (DRM) schemes.

"There seem to be new codecs every day and they appear to change at Web speed," said Fellows. "I don't have the human resources to track all these new codecs and their changes. It evolves so fast," he said of his 120-person company that has delivered more than one million set tops to date.

Just among video codecs, MPEG-2 is used for most DVD and cable TV content, but both platforms are migrating to MPEG-4. Some Web video services use proprietary codecs such as the one in Adobe Flash. Microsoft recently announced its own Flash-like product called Silverlight. Others use H.263 and motion JPEG. Personal content sometimes uses the DV codec.

"The content is fragmented in many different formats and devices have to support them all," said Bhupen Shah, the chief technology officer of Sling Media.

Sling's box tries to decode any incoming stream and its DRM, then send it on in whatever format a receiving device can handle. When possible, the box converts streams to analog before re-digitizing them for transmission.

"There are too many business models at play to have interoperable DRM at this point," said Ken Morse, VP of client architecture at Scientific Atlanta, now part of Cisco Systems.

The company develops its own ASIC for set tops that now includes eight cores including dedicated blocks for encrypting and decrypting AES traffic to handle DRMs, Morse said.

"The silicon vendors don't understand the DRM problem correctly. All we want is a place to store a root crypto key safely in a chip," said Fellows, frustrated by chips that also build in video processing capabilities he doesn't need.

"There are no dedicated network TV silicon solutions today," said Tsai of HP.

Costly approach
For its Media Smart TV, HP took the approach of using a variety of chips aimed at networked DVD and telecom systems. Software from the various vendors did not blend together well and they required independent blocks of memory, creating extra costs, he said.

However, that approach was better than using programmable DSPs orworse yet, VLIW processors that appear in some systems. Those solutions are difficult to optimize for all the very different media and control functions they handle, Tsai said.

"It's perpetual job security for the software guys," he said. "In general, people with consumer, computer and chip experience are very rare," he added.

A representative of Texas Instruments said the company is currently seeking feedback on its plan to make a single-chip version of its two-chip DaVinci chip set aimed at Internet TV systems.

Cable TV and telephone carriers rolling out managed networks for TV have the advantage in quality, said Morse of SA. Their target is to have no more than one picture defect in every 2hrs of viewing, and two-thirds of all carrier set tops now shipping already support HDTV.

Their latest set tops also support IP downlinks at about 10Mbps, a figure that will go up to 120Mbps in the next generation. Morse said carriers will bridge "best of the Web" content on to their managed systems. The Open Cable Application Platform, a software stack developed for cable TV operators, is now being deployed and will be a foundation for Web content, he added.

What the carriers lack is the full breadth of Internet content. Apple Inc. tried to strike a balance with its Apple TV that requires pulling content from its large, but limited iTunes service via a Macintosh computer over Wi-Fi. To reach out to the broader Web, Apple cut a deal to make YouTube available over Apple TV.

Carriers have their own fragmentation issues with the proprietary electronic programming guides (EPGs) used by different carriers and middleware companies.

"The standardization is very good for video streams on telco networks," said Fellows. "The proprietary parts come in with DRM, conditional access and EPGs," he said.

"There's a huge non-standard meta-data environment in telco TV networks that needs to shake out. That has held them back a bit," Fellows said.

- Rick Merritt
EE Times

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