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A remix is usually the same artists audio tracks that have been re-engineered (remixed) into an alternate interpretation of the song.

Marshmello, an American electronic music producer and DJ, won the case as Judge Philip S. Gutierrez held that Arty had contractually given up ownership of the ...

When something is remastered, its typically from the original files before it was mastered. So a new mastering engineer can redo that step.