use perceptually in a sentence.
If you cut it down, and it's perceptually the same, then it's an obvious win no?
It's not even "perceptually 3D" though.
When they say perceptually lossless, by whose perception do they mean?
So, in the case of jpegs, their compression is not lossless, they just claim the losses are not that perceptually visible.
Measuring the point where something becomes perceptually lossless is quite difficult because, by definition, you're measuring at the bounds of perceptibility.