What if I train an AI model on exactly one copyrighted work and all it does it spit that work back out?
eg if I upload Marvels_Avengers.mkv.onnx and it reliably reproduces the original (after all, it's just a fact that the first byte of the original file is OxF0, etc)
A work that is “substantially similar” to a copyrighted work infringes that work, under US law, no matter how it was produced. (Note: Some exceptions apply and you have to read a lot of cases to get an idea of what courts find “substantially similar” .)
I wrote "some exceptions apply" to try to avoid getting into the weeds, but yes, independent creation is an exception. Other exceptions include out-of-term works, public domain, Mise-en-scène (e.g., stock characters), fair use (a huge can of worms), etc.
eg if I upload Marvels_Avengers.mkv.onnx and it reliably reproduces the original (after all, it's just a fact that the first byte of the original file is OxF0, etc)