The video is pretty good too:
https://rave.dj/dBgxMMEtR9j-nw
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Edit: Here's an example of an utter failure that illustrates my hypothesis: it mixes a song that has a traditional verse/chorus/verse structure with a techno track that's a monotonic crescendo. The algorithm doesn't know what to do about it (the correct answer, although not leading to great music, would be to use parts from the begginning of the crescendo track so not to overpower the pop song.)
https://rave.dj/-Ls2Nu6CPD0Ssw
Edit 2: Here's an easy one it gets wrong: track 1 has great loopable instrumental grooves that go on each for a few bars before rap vocals kick in. Track 2 is a person talking. It should not be overlapping vocals, it should just highlight the instrumental loops.