Tandberg Television next week will show off a switched-digital-video system based on the company’s OpenStream video-on-demand platform.
The OpenStream Switched Digital Video system can support multiple bit rates, from 2 to 20 megabits per second, and allows operators to mix MPEG-2 and MPEG-4 Advanced Video Coding formats. SDV conserves bandwidth by transmitting a less-watched channel only when a subscriber requests it.
According to Tandberg vice president of system architecture Michael Adams, there are more similarities than differences between SDV and VOD. “VOD is always unicast; and SDV is sometimes unicast, sometimes multicast,” he said, “but otherwise they’re the same.”
Adams said the product will support the two de facto SDV implementations that have emerged in the market: one developed by Time Warner Cable and Comcast’s Next-Generation On Demand architecture SDV service extension.
Tandberg also expects to integrate OpenStream SDV with Imagine Communications’ variable-bit-rate and statistical multiplexing technology, which Imagine claimed can provide 50% more streams per quadrature-amplitude-modulation channel. With the Imagine system, three HD variable-bit-rate streams can occupy a QAM channel, compared with two HD constant-bit-rate streams.
Many operators are in the initial stages of launching SDV. Comcast is currently running SDV trials in systems in Denver and New Jersey and expects to go live in the second half of the year. Time Warner Cable had deployed the technology in eight divisions at the end of 2006, and it is aiming to have it in three-fourths of all 23 divisions by the end of 2007.
“Most of the market has yet to choose an SDV vendor, so we feel the timing is good,” Adams said.
Tandberg has not announced product availability or pricing for the OpenStream SDV product.
Other vendors in the SDV space include BigBand Networks, which claimed that its SDV gear has been deployed in systems representing more than 5 million homes passed, as well as C-COR, Harmonic, Motorola and Scientific Atlanta.