Inside Cablevision's 'RS-DVR'
The fight is over whether there are separate ownership rules when content is stored on a service provider's storage system delivering the content through a networked DVR, rather than the user's own equipment. Cablevision once again will take the old Sony Betamax decision to task, contending that the RS-DVR should be protected in the same way that an in-home DVR is today. Cablevision argues that its RS-DVR is no different than an in-home DVR, because if 1,000 customers tap the RS-DVR to record a specific program, the system is designed to make 1,000 individual copies. Further, each copy is accessible only to the customer who made the original recording request.
If Cablevision's appeal is successful, it could serve to define how other cable operators move ahead with their own network-DVR services. Likewise, a successful appeal could be a boon for more than a handful of vendors that are linked to Cablevision's RS-DVR project.
Privately, some observers believed Cablevision's motive with the RS-DVR was to get programmers to the negotiation table to carve out network DVR deals -- akin to the axiom that it is easier to ask forgiveness than it is to obtain permission.
But that argument becomes a tougher sell when one considers the technical groundwork Cablevision had already completed on the project. Much of that detail is copiously outlined in a 38-page decision handed down on March 22 by U.S. District Court Judge Denny Chin, who ruled that Cablevision's RS-DVR would violate the copyrights of a raft of plaintiffs, including Disney, Paramount Pictures, Twentieth Century Fox, CNN, and NBC.
A look through the decision clearly indicates that Cablevision had taken the necessary technical steps to deploy the RS-DVR, though it stopped short of doing so, agreeing to mothball the project pending the judge's decision.
Now that this innovative and controversial service appears to be back in play, here, according to the judge's decision, is a brief synopsis of how the platform would work and the roles some vendors played in its creation.
The service originates at the "BarcoNet" (Scientific Atlanta bought BarcoNet in late 2001), a closed circuit network that receives Cablevision's linear programming. That programming, called the aggregated programming stream (APS), comprises packets of data, with each packet tagged with a program identifier (PID).
The system then splits the APS into two streams, the second of which is piped to the BigBand Networks Inc. (Nasdaq: BBND) Broadband Multimedia Router (BMR). There, the BMR "clamps" the stream, converting the variable bit rate (VBR) stream into a constant bit rate (CBR) stream. (Note: the CableLabs CBR spec for standard-definition VOD streams is 3.75 Mbit/s; the CableLabs "safe harbor" bit rate for HD-VOD is 15 Mbit/s.)
During the clamping process, portions of the program are sent to the BMR's buffer memory. The BMR then encapsulates the information by converting the APS into a number of single program streams and placing packets in those streams into larger packets called User Datagram Protocol (UDP) packets. Each UDP packet is assigned a port number that identifies the TV channel to which it belongs.
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