Total neophyte here, and not even sure if this is the right place to be posting this question. Please excuse my complete ignorance as to how any of this actually works.
How would one go about creating a Tool-Assisted-Speedrun for use in the Aleph One engine? From what I can gather, saved files (or possibly recordings?) are actually a series of inputs along with a map file and other misc files that are replayed by the engine when you watch it? Would that be an accurate description? If so, how are the inputs from the player actually recorded and written to output, and how are the files read by A1 itself? Is it possible to manually encode a series of inputs for the playback to read?
Anything's possible if you're brave enough.
There's some other speedrunners that have posted on here and on the Marathon Story Page forum. They might have some answers, maybe not. Other than that, you'd probably just have to look at the engine code yourself, maybe.
Films are just a set of user inputs, correct. You should be able to create one manually with a hex editor or some Python code. There is no documentation, so you'd have to read the source code to figure out the format.