Nvidia's DLSS Technology Analyzed: It All Starts With Upscaling

[cryoburner]

Can someone explain what's going on in the last picture and why the background is SO much better compared to no-AA? Even the cliff texture.

I pointed out what appears to be going on in an earlier post. What you're seeing is not the background looking "better" but rather the upscale and sharpening process simply counteracting the depth-of-field effect that's intended to be there...

In the shot with DLSS enabled, the background and its vegetation look better than the screen captures with no AA or with TAA enabled.

You seem to have missed something big here, that I noticed immediately in the first two comparison shots, and again in that car image. The reason the background looks "better" in these stills, is that DLSS is effectively removing much of the depth of field effect. The backgrounds are supposed to be blurry in those shots, because those parts of the scene are intended to be out of focus, to simulate a camera lens, giving the image some depth. Not being as blurry as it should be in those parts of the scene is another artifact that effectively makes the DLSS image quality worse. DLSS is applying a sort of sharpening filter to the upscaled output, and while that helps the image to look sharper than just a regular upscale, it has the side effect of also sharpening things that shouldn't be sharpened.

You should be able to see this well in that first comparison image of food when viewed at full size. With no AA, the central part of the image is sharp and in focus, but the background to the upper-right, as well as the edge of the tortilla in the foreground, both show soft focus effects, as they should. With TAA applied, the entire scene gets a bit blurry, though the out of focus areas are still relatively out of focus, maintaining some depth. Now in the DLSS image, the central part of the shot that is supposed to be sharp and in-focus is actually a lot blurrier than TAA. However, the background and foreground are actually sharper than they should be, since the sharpening filter has effectively removed most of the focal effect that was supposed to be there. The net result is that instead of having the subject of the image sharp and in focus, and the background and foreground blurred to provide depth and help make the subject stand out, everything is at roughly the same somewhat-blurry level of focus, making the DLSS image look flatter.

You can clearly see this artifact again in the "bending over" image, as well as in the car image. In both case, the trees in the background get sharper than they should be, while the subject of the image, the person or car, gets blurrier than even TAA. Some people may prefer to not have the depth of field effects, but in that case, turn them off. If the effect were disabled, you would clearly see that using no AA produces the sharpest image, TAA is somewhat blurrier but removes aliasing, and DLSS is significantly blurrier still. The only reason it looks "better" in some specific parts of some images, is that it's counteracting a graphical effect that's supposed to be there.

Now, presumably a game could apply depth of field after the upscale and sharpen process to avoid this removal of the effect. In that case, however, everything would be blurrier than TAA with the effect active, and I suspect that was not done for this demo, since Nvidia likely preferred to make at least some parts of the scene look sharper than TAA, while providing better performance.