Switched Digital Video
Switched Digital Video, or SDV, is a delivery method for channels over a cable television network. While traditional cable infrastructure delivers all available channels at once to subscribers' receivers, SDV will deliver only the channels currently being accessed.
The use of Switched Digital Video (SDV) helps a cable provider to save considerably on bandwidth demands down the line, and allows the number of channels available to inflated far beyond the limits of traditional cable television systems. The system requires a receiver to send an upstream signal to a cable headend to request a signal be sent down the cable, meaning the receiver must be compatible with the system to change the channel.
By the end of 2009, an estimated 35 million households in the United States had a cable television feed that depended on Switched Digital Video (SDV) technology to deliver channels to the TV.
A negative consequence of widespread SDV use is that it will lock out third-party digital video recorders (DVRs). The Cable TV industry has responded to this fear with the tru2way platform. TiVo has complained to the FCC that SDV will enable cable companies to lock out anything other than receivers that they choose for their networks.