I don't know if you can really know. Netflix doesn't stream the full lossless soundtrack, they don't offer that sort of bandwidth; they use DD+ (maybe with Atmos metadata of some sort) but hard to know what the provenance is. A friend of mine had a torrented 1080p rip of 2049 with the AC3 soundtrack (the base Dolby Digital, but again no real provenance on how that was obtained) and while good I was astounded at the difference with the bluray with the actual Dolby Atmos/True HD soundtrack (I don't have Atmos so I get the DolbyTrueHD core only, but didn't really expect that much of a difference among any of them). I'd test on Netflix now but it's not a current offering (I first rented the bluray from Netflix then bought the bluray later). I've seen others comment on the difference as well, tho. It could have been a level thing but still when I compared the rip/AC3 to my bluray, it just seemed like a different mix. YMMV....