US cableco uses switched video for HD

US cable operator Cablevision has confirmed that it will offer 15 high definition channels from sibling company Voom using switched digital video.

The technology allocates capacity on an on-demand basis, using bandwidth to deliver services only when they have been requested by a customer's set top box. This enables cable operators to make a greater number of bandwidth-intensive services available, as swathes of spectrum do not need to be reserved in block.

Cablevision plans to roll out a new fleet of high definition set top boxes that support the technology and will offer them free to subscribers who possess devices that are incompatible. Some equipment with built-in digital cable tuners, such as some models of TiVo digital video recorders, will require a switched digital "tuning resolver" to ensure continued reception of channels delivered using the system.

Switched video for the delivery of linear TV channels has yet to be deployed by a UK cable operator. Last November, Virgin Media's content chief Malcolm Wall admitted that the service is "bandwidth constrained" and will only "add HD channels on a selective basis".