I've developed a habit of browsing a local university's asset disposition website lately, and they're frequently selling off Video Processors, Digital Signal Processors, and Control Processors (examples: FSR INDIE-400HD, Shure DFR11EQ, and Crestron CP2E). These are often 1U rack mount devices.
What is all this?
I suspect it has to do with large presentation halls or portable event systems, given other stuff that shows up at the same time. Maybe broadcast/editing?
It's all for feeding projectors. Universities have baroque AV setups, hundreds of presentation rooms with projectors and PA systems, hardwired video and audio feeds to the front and back of the room, and often automation as well - a lot of podiums have little control panels with illuminated buttons that raise and lower projector screens, curtains, etc. It's all very byzantine.
These projectors used to be very low resolution - standard def for a while, then 640x480 or 1024x768; if you walked into a classroom with a laptop or a VCR or whatever there was no telling whether you'd be able to output something compatible. So they install these processors that convert everything to everything.
Generally speaking the processor/scaler gear is very nice. It's expected to take any conceivable input and coerce it into the format du jour, and to do so with no significant delay or the need for manual adjustments. You put anything in, and no matter what, you get a picture out. It might not be the prettiest conversion but god damnit, you're getting a picture, not a "NO SIGNAL" that forces you to interrupt your speech to dick around with a computer.
Of course, a lot of the stuff on auction is only there because it's extremely outdated, with the only outputs being VGA for instance. If it does HDMI or DVI out at 1080p, there's really no reason to ever get rid of it, but it does happen. I have an extron scaler intended for this kind of environment that works extremely well and outputs HDMI, got it for $30.
There's other stuff in this field that's more abstract. Extron is infamous among e-waste handlers for their enormous signal routers - devices that switch a ton of possible inputs, sometimes to a single output, or sometimes between many possible outputs, what they call a matrix switcher. You can imagine what these are used for, notionally, but it's hard to put an example into words, and more importantly, they're utterly uninteresting to most nerds, who are typically content to just swap cables rather than use any kind of switcher at all.
Bonus Fact: the Tricaster, Newteks now-flagship video streaming system that replaced the Video Toaster series, was originally designed for this same application. It was intended for enhancing presentations, and the "Tri" referred to the three possible output formats: live display on a TV (via composite video), live display on a projector (via VGA) and internet streaming (via IP.)
