Imagine a More Efficient Stream
By Matt Stump -- Multichannel News, 5/14/2006 8:00:00 PM
Imagine Communications wants to help cable operators save bandwidth by making the delivery of video-on-demand streams more efficient.
To get there, Imagine is pitching a new encoding scheme that will use less space on a cable network as VOD streams travel to the home.
The trick is to use the same variable bit-rate encoding technology operators use to transmit broadcast channels to the home, said Marc Tayer, senior vice president, marketing and business development at Imagine, based in Cardiff by the Sea, Calif. Such encoding, which removes bits of data that don’t change from one frame of video to the next, will allow cable companies to push more VOD streams through their current pipes, he said.
Cable operators use variable bit-rate encoding techniques for standard-definition cable channels to squeeze more channels into quadrature amplitude modulation devices, which process data and put the bits onto radio waves that carry them through the network, Tayer said. The squeezing means the cable operator doesn’t need to buy as many modulation devices for processing locations in a network to handle a particular program lineup.
Current QAM devices can process a total of 38 Megabits of data per second, Tayer said. If all television programs are encoded at a constant bit rate, each signal requires 3.75 Mbps of processing each second, meaning operators can push about 10 channels through a quadrature amplitude modulation device at one time.
By using variable bit-rate encoding, operators can process 15 to 17 channels in each device, Tayer said. “This has never been used for VOD,” Tayer said. “It’s all been done at constant bit rate.”
As VOD usage climbs, he said, “the bandwidth problem multiples. With VOD, every stream is unique. It uses a lot of bandwidth. Digital broadcast has been able to take advantage of variable bit rate technology,” and Tayer believes cable operators can do the same for VOD.
“We’re implementing our core technology in software,” he said, that runs on a gateway device next to a VOD server. “We’re a plug into the existing infrastructure. We don’t require them to throw out their existing investments.”
Any VOD program a subscriber orders would be streamed from the VOD server through the Imagine gateway, which would encode the stream using variable bit rate technology.
“What we add is the ability to get more streams at the same quality within the same infrastructure,” Tayer said.
Tayer said Imagine is not ready to releases specific pricing for its hardware and software.
Imagine recently closed a $9.2 million funding round, led by Carmel Ventures and Columbia Capital. The company plans to showcase its product at next months, Society of Telecommunications Engineers’ Cable-Tec Expo in Denver.
Why Haven't CableCards Taken Off?
10/02/2009Channel Boost
01/13/2008BIT RATE
12/07/2008What Comcast's Crunched HD Looks Like
03/29/2008
