Channel Boost
Imagine Debuts System to Optimize Broadcast Signals
by Todd Spangler -- Multichannel News, 1/13/2008 7:00:00 PM
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BIG SAVINGS?
SDV, VOD ON DECK
Cable operators maxed out on bandwidth may be able to put a powerful new running back into the high-definition TV ballgame.
Startup Imagine Communications this week (Jan. 14) is set to take the wraps off its first product: a system it claims will let operators stuff 50% more HD or standard-definition channels into the same amount of bandwidth, without hurting the quality of the video.
The ICE Broadcast System optimizes MPEG-2 video streams, using Imagine's proprietary processing algorithms to re-encode that video at a lower bit rate while supposedly preserving image quality. The system then statistically multiplexes the streams to allow up to three HD or 15 standard-definition channels to fit into a 6-Megahertz quadrature amplitude modulation carrier.
San Diego-based Imagine, founded in 2005, originally began developing a way to improve the efficiency of constant bit-rate video-on-demand streams.
But with competitors like DirecTV, Dish Network and Verizon Communications targeting 100-plus HD channel lineups in 2008, cable customers had a more urgent need to maximize linear broadcast programming encoded at variable bit rates, said Marc Tayer, Imagine's senior vice president of marketing and business development.
Imagine would not disclose pricing for ICE Broadcast. But Tayer claimed it would be less expensive, on a per-subscriber basis, than alternative techniques for expanding or optimizing bandwidth. That includes switched digital video, node splits, spectrum overlay, upgrading to 1-GHz or migrating to MPEG-4.
BIG SAVINGS?
According to Imagine, its system requires no changes outside of the headend, because the video is delivered in standard MPEG-2 format. With switched video, MPEG-4 and plant upgrades all require some modification at the set-top level.
In Imagine's calculations, the potential bandwidth efficiencies are considerable.
Using the startup's video reprocessing and multiplexing technologies for broadcast, switched digital video and on-demand programming, a cable operator could reclaim more than 100 MHz of spectrum, or 18 QAMs, Imagine claimed.
The assumption is that an operator is broadcasting more than 100 standard and up to 75 HDTV channels, as well as optimizing VOD streams.
But it's not clear how much space the system requires. Imagine will only say that “multiple” one-rack-unit-high ICE Broadcast Processor servers would be needed per QAM to process video in real time.
Imagine said ICE Broadcast currently is being deployed by three cable operators, which it has not identified. According to people in the industry, Comcast Media Center is already using the system to deliver HD programming to customers of its HITS Quantum service.
Operators plan to use ICE Broadcast in different ways, Tayer said. Some will use it for nationally distributed programming, while others take a regional or even headend-by-headend approach. “It's not one-size-fits-all,” Tayer said.
SDV, VOD ON DECK
Meanwhile, Imagine's switched digital video and VOD product lines are still in the works.
The switched-video staging processor, which takes an incoming MPEG-2 stream and outputs it at a fixed bit rate, will be available in early 2008, Tayer said. For example, it can clamp SD video into standard 3.75 Megabits-per-second streams for delivery over a switched digital video system. “It's basically higher quality constant bit-rate video,” he said.
A second switched-video product from Imagine, due later in the year, will statistically multiplex variable bit-rate streams delivered via an SDV system, theoretically achieving similar bandwidth savings as the ICE Broadcast system. Imagine expects to introduce a separate VOD product for preprocessing on-demand video libraries in the second half of 2008.
Imagine was founded by two former BigBand Networks executives. Last year the startup was sued by BigBand, which alleged Imagine had infringed on three patents related to video-processing and bandwidth-management technologies.
Imagine denied the allegations.
| How It Works |
|---|
| Imagine claims its system can pack 50% more broadcast channels in the same bandwidth. |
| SOURCE: Imagine Communications |
| Step 1: MPEG-2 source video is delivered to Imagine's “second pass” ICE Broadcast Processors. |
| Step 2: Using proprietary algorithms, those processors reduce bit rate while allegedly maintaining video quality. |
| Step 3: The reprocessed MPEG-2 streams are passed to Imagine's ICE Multiplexer, which combine them for Multiple Program Transport Stream (MPTS) digital broadcast over cable. |
| Step 4: An operator is then able to carry three HD or 15 SD signals in a 256-QAM channel without degrading video quality. |
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