I know I've seen this mythical device in the past for composite video signals., but it's been some time. Does anybody know of a similar device for SDI? I want to dim video signals to prevent light pollution from a conductor camera during blackouts via DMX. Any lead would be most helpful.
I have not myself run across an SDI-passthrough box that would dim out the video by DMX control -- and it's the sort of thing I'd notice, and seems like it'd be useful -- but I think you'll find that putting a DMXdowser in front of the camera will be the closest you'll get.
Maybe look for an SDImixer or switcher and run a black signal as one of the feeds. Depending on the mixer and lighting console, it ought to be possible to cobble together switching or cross fading the feed based on a blackout event.