This object turns VANC service processing on or off for this input, where VANC refers to vertical ancillary data such as closed captions or active format description carried in the vertical blanking interval of an SDI video signal. An admin cares because disabling this stops the device from extracting and forwarding ancillary services like closed captioning, which downstream systems such as a set-top box or compliance recorder may depend on for regulatory or display purposes. A cable headend passing through video that includes EIA-708 closed captions would need this object set to yes(2), or those captions would be silently dropped even though the video and audio pass through fine.