I believe I have completely worked out the internal functioning of the video toaster, a device which nobody has ever been able to explain to me in any detail, and which should not have been able to exist at the time it did and for the price it cost. I did this by thinking about it real hard, and reading six vague sentences from its designer.
The shame is that there's absolutely nobody I could run this by for confirmation other than the guy who designed it, because anyone else who thinks they know would either be completely guessing (but incredibly certain they're right) or would be a crotchety old fuck who would be so rude about what I got wrong that I would delete his email.
anyway i'm pretty convinced it contains nothing more than an analog mixer, two framebuffers and a pair of RAMDACs, and literally everything else is done through extremely clever ways of mapping prebaked bitmaps and lookup tables into values to drive those devices.
I'm going to be expanding on this in the (at this point 28,000 word) video I'm composing on the subject, but I just keep thinking about what I've learned and being staggered by it
the Video Toaster, an addon card for the Amiga which integrates deeply with a piece of software that runs under AmigaOS, has no ability to talk to the Amiga at all. it plugs into the machine's video slot, which is - very literally - equivalent to a VGA port, or perhaps a DVI port. there are no address or data lines. there's nothing at all except sync signals and RGB values. all commands have to be encoded into pixel data. fucking madmen.
thanks to @kyogi linking me to a page that contained the toaster developer guide (oh my god) I have now confirmed that I got everything right. which is shocking even to me. the one thing I missed: they use the TTL RGB lines on the Amiga's video interface to get cleaner values for keying operations. alright, fair.
the video about this thing is going to probably be like four hours long so i'm just going to "spoil" the real "oh fuck off" reveal of it because I feel like it should be discussed publicly more than I feel like having an "omg" moment in a video almost nobody will watch all the way through.
the toaster has lots of effects that do things like wrap the camera image onto a sphere and whisk it offscreen. that was impossible with the technology of 1990, but since the Toaster contains a digital framestore with a RAMDAC, and that can be programmed arbitrarily, for every pixel it outputs you can instead tell it to grab pixel data from another place in the framebuffer. instead of plotting pixel 5,5 at screen position 5,5, you can tell it to put 10,10 there. and that's free; it costs nothing, as long as you don't need to spend any time loading the target coordinate into registers.
well, the amiga's video output delivers an RGB value for every single pixel on the screen. so... with a bunch of precalculation, you can turn a real 3D transform into a lookup table, which instructs the Toaster on how to fake that transform solely by relocating pixels. then, to get that into the toaster, you render it into a 60fps animation that plays on the Amiga's screen, where each pixel is actually a set of packed coordinates. the Toaster's RAMDAC converts them back into numbers, then retrieves whatever pixel they point at, and in this way it's prevented from having to do any real work. the Amiga also does no work. all the work was done when the effect was designed.
the end result is that, if we could see what's on the Amiga's video output, it would be a wild clusterfuck of rainbow noise with a vague shape showing through. i would love to be able to do this, but i don't currently have the technology; eventually, I would like to.

