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Inserting ads in a digital world

Digital compression technology is allowing cable operators to dramatically expand their programming. But working with MPEG-2 compression also introduces a new level of complexity to headend operations.

Since MPEG-2 has frames of varying sizes, switching from one MPEG-2 feed to another is a tough technical challenge. DTV broadcasters haven't had to deal with this much, since most are decompressing incoming MPEG-2 satellite feeds to baseband, inserting their local branding and commercials, and then recompressing them for broadcast. But such a scenario isn't economically or technically feasible for cable operators looking to insert commercials on a large number of MPEG-2 compressed channels, particularly when they are "cherry picking" or "grooming" channels from a digital multiplex being delivered via satellite.

Compression suppliers DiviCom and Terayon will show solutions to the MPEG-2 insertion problem at NAB this week. DiviCom has developed a product called TransRater, which can change the bandwidth of an MPEG-2 feed without decompressing it. And Terayon will introduce the CherryPicker Ad Splicer, which will integrate with existing digital ad servers to insert local MPEG-2 commercials into digital channels.

DiviCom's TransRater can take an 8-Mb/s MPEG-2 feed and change it to 6 Mb/s without decoding or re-encoding, says Director of Product Marketing Eric Norton. The system, which will sell for $25,000 to $35,000, can change variable-bit-rate channels to constant-bit-rate, as well as support frame-accurate splicing.

Terayon's CherryPicker Ad Splicer can handle the splicing for a multiplex of 12 to 18 channels for less than $25,000, according to Stephen King, vice president and general manager of Terayon's digital video group, which is less than the $40,000 an operator would spend to decode and re-encode an MPEG-2 feed. For customers who have already purchased Terayon's CherryPicker statistical multiplexing system, the splicer is a $7,000 software option.