If I loaded a copy of Toy Story into my video editor and cut it up to change it into a story where Woody actually killed Buzz Lightyear and is subsequently executed for it by Sid, agent of justice, this would obviously be a derivative work that I could not legally share with the world.
But what if I just wrote down and published the steps that I went through to produce my version, in such a way that another person could easily replicate it on their own copy of Toy Story? Like:
- Remove 0:33:43.00 - 0:33:48.12
- Insert scream.wav from Hank's Free Sound Kit at 0:55:32.04."
Would those instructions themselves be a derivative work? Or be illegal for any other reason, e.g. because they are instructions for an infringing act? If so, what's the difference between that, and a YouTube tutorial on changing a specific dress (with copyrighted design) into a mini skirt (which I presume would be allowed)?
But, assuming this is legal, how far can we stretch this concept? What if instead of writing manual steps, I create and distribute a computer program that automatically performs them on any copy of Toy Story the user provides? Would the convenience this provides affect how it is viewed? And what about that it no longer gives the user the option to interpret the steps differently, for creative or legal reasons?
What if the program requires a very specific byte-for-byte copy from a legal source, like "all files in the VIDEO_TS folder of the Director's Cut DVD, PAL edition, batch #6588"? You could argue that indicates I have likely performed said steps myself and produced a derivative work, even if I haven't distributed said work.
What if the required file is from an illegally distributed torrent release?
This is getting technical, but what if I just XOR my edited version with some other large file, say an Ubuntu ISO, and publish the resulting key? Another person could XOR that key with the Ubuntu ISO (which they can download freely) to get Toy Story: Buzzkill.
On the one hand, the key could be described as a long list of instructions to turn one thing into another, no different from the initial concept. But on the other hand, it could be viewed as just a very weird form of encryption, and should be no more legal than just publishing my movie as a password-protected (thus encrypted) ZIP file.
Where do you think the line is drawn?