DiviCom Boosts Digital Insertions


DiviCom Inc. is set to bring new technology to market this week that promises to vastly streamline the steps involved in customizing digital-TV channels and multiplexing them with data signals across the multiple hops from program originators to end-users.

The innovations are packaged in two product categories. One is devoted to processing MPEG-2 signals and inserting new content, including ads, into the channel stream without requiring them to be decoded and re-encoded.

The other uses every available bit of bandwidth to maximize the amount of "out-of-band" data that can be mixed into the stream "on the fly."

The move by DiviCom comes as the ability to insert advertising and other digital content into the MPEG-2 channel without going through the decoding-encoding process becomes a key requirement not only in broadcasting, but also for cable.

Other companies-including Cisco Systems Inc.'s V-Bits Inc. unit and Terayon Communication System Inc.'s Imedia Corp., the pioneer in on-the-fly ad insertion into digital TV-will show such capabilities at next week' s National Association of Broadcasters conference.

This marks a big step forward in cable operators' and broadcasters' abilities to make a business case for digital TV.

Local ad insertion has suddenly become a revenue option for cable operators due to the surge in the market base for digital programming, noted Larry Grunewald, director of marketing for the "RateMux" and related products at Cisco.

"I think a lot of people didn't expect there to be enough viewers of the digital channels in any given local market to merit selling ads for some time to come. But now the viewer numbers are becoming significant selling points in many markets," Grunewald said.

According to an analysis of the broadband consumer market prepared for the National Cable Television Association by Paul Kagan Associates Inc., the total number of digital-TV subscribers in cable at year' s end was nearly 5 million.

So far this year, the sign-up rate is about 95,000 per week-more than double direct-broadcast satellite's growth-putting cable on course to hit about 10 million digital subscribers by year' s end, the report said.

To make local ad insertions possible, programmers and operators must agree on a standard for cue tones in the digital stream, which is a more complex process than the cue-tone transmission that takes place over 6-megahertz analog channels.

With many MPEG-2 channels multiplexed together and using variable amounts of bandwidth within a 6-MHz channel, the cue tones must be contained within the MPEG signal. This requires a uniform approach in the encoding process across multiple vendors.

"There' s real momentum behind setting the parameters of cue tones for local digital ad insertion," Grunewald said, adding that work in this area is nearing completion among the cable and broadcasting standards groups.

MediaOne Group Inc. this week will become the first MSO to install a digital-to-digital local ad-insertion system, using gear supplied by nCUBE and Terayon to support the process in 12 Los Angeles systems.

Now, with broader vendor support for such capabilities, the stage is set for wide-scale emulation of what MediaOne is doing, nCUBE president Michael Pohl said. "This represents a turning point in the ad-insertion industry," he added.

At DiviCom, new "Trans-Rater" technology improves on existing technology by reducing equipment expense at the headend, while still giving service providers the flexibility to customize the compressed digital stream, director of product marketing Eric Norton said.

The technology comes in two versions, he added. One is for customizing the video content itself, another can also handle on-the-fly ad insertion.

The process involves more than straight insertion of new bits into the bit stream, Norton said. "The TransRater technology is a way of turning a variable-bit-rate input into a constant-bit-rate output while maximizing bandwidth efficiency in the process," he added.

The process offers such features as frame-accurate splicing, format conversion, pixel-level processing, logo insertion and overlays.

When the version of the system that supports ad insertion is used, the Trans-Rater technique uses seamless frame-accurate splicing to enable real-time ad insertion, as well as insertion of local programming with no visible picture-quality deterioration, Norton said.

Three techniques are applied to accomplish these tasks. In instances within the bit stream where the bit rate falls below the CBR output parameter, new bits are "stuffed" to fill the stream to the optimum level.

And where there are variations above and below the CBR rate within a given time domain, the system uses either requantization-a means of exploiting very small bit-rate variations-or DiviCom' s proprietary full-transcode technology to maximize efficiency across large bit-rate variations.

"Where there are variations in the bit rate from as high as 7 megabits per second to as low as 4 mbps in a given MPEG channel, transcoding allows us to take advantage of those gaps as we multiplex all of the channels into a CBR output," Norton said.

DiviCom is also making it possible to pack more data into the digital-channel stream, using what it calls "Look-Ahead" encoder technology, which finds space for data to be transported alongside the video without compromising video quality, Norton said.

All of the empty points in the multiple channels of MPEG-2 programming that might be packed into a 27-mbps 64-QAM (quadrature amplitude modulation) or 38-mbps 256-QAM channel can be used to carry the data signals that transport electronic programming guides, encryption information and specialized interactive applications.

"You won't have to fix a hard pipe for data anymore, which gives you a lot more bandwidth to work with in the data space," Norton said. "In effect, you' re getting free bandwidth for data.