For the past year-and-some, I’ve been attending meetings of the Digital Video Broadcasters’ CPCM, a standards-group that is writing Europe’s equivalent to the Broadcast Flag. I’ve just filed a report with a British House of Commons committee that is holding an inquiry into the digital television transition. This is one of the very first detailed papers on the subject, and I hope to release more as I’m able — we’ve limited ourselves to discussion of the elements that have been made public by the chairs, and as more of this becomes public, I’ll be publishing more on the subject.
The DVB CPCM specification is being developed in closed-door meetings. Joining DVB costs 10,000 Euros per year, and membership is only open to manufacturers, broadcasters, studios, and academics. Its proceedings and intermediate work products are not widely published or publicized.
Most of the details of CPCM have not been publicly disclosed. The material in this section is drawn from two public presentations, one given by the Motion Picture Association of America’s (MPAA) Vice-President, Jim Williams, at the DVB World Conference in Dublin in March 2005, the other given by DVB Content Protection Technical Group chairman Chris Hibbert to the MPAA’s Copy Protection Technical Working Group in Los Angeles in January 2005.
CPCM is a system to “enable…current & future business models.” To accomplish this, CPCM employs three areas of specification:
* Usage State Information (USI). This is a set of commands that can be embedded in a TV programme. These commands instruct a DTV receiver to apply particular restrictions to the programme received by the device. Elements of USI include “Copy Once” and “Copy Never,” “Proximity Control” and “View No More.” The level of control afforded by USI is particularly extensive and fine-grained compared to the “rights expression” in older use-restriction schemes. This more precise level of control is intentional and regarded as beneficial by its authors.
* Definitions. CPCM defines new terms, “Authorised Domain” and “Local Environment.” The definitions of these terms effectively set the boundaries of what a valid family is (“Authorised Domain”) and how far apart two devices are allowed to be in order to interact (“Local Environment”).
* Compliance rules. This is a set of rules for DTV device manufacturers. They limit the choices manufacturers can make in developing their products, and require them to implement technological measures they might not choose to use otherwise.