Under the old copyright paradigm, that's always up to the judge presiding over the copyright suit to decide.
Happens all the time in the music industry where other records are frequently sampled, and then used in an altered form. The judge (who knows nothing about the music, or the technology) looks at it, and looks at it, lawyers argue about it for a few months (everyone's getting paid $250/hr if not more) , and then the judge says "ok, it's ... new art". Or "it's infringing".
The entire thing is just a mindboggling pile of bullshit.
I'm in the software industry and that's generally how many think about software patents. IP laws, to me, are pretty ridiculous. I like Ben Franklin's approach which was basically along the lines of keep innovating and adding value and leave everyone else behind. Anything backed by the coercive force of government is, to me, a bad idea to begin with. Good ideas don't require force.
That said, I also deeply care about original creators and hate to see them being taken advantage of. I hope our technology can provide solutions to provably show (via notarization through the blockchain, maybe?) who the original authors are and reward them accordingly.
The LBRY project are doing some interesting stuff along these lines.
http://LBRY.io
That sounds really cool, thanks for sharing. I've heard a little here or there about it. Nice intro video. I'll keep an eye out for it.