Explanation by mbucchia:
Q: What is the motion reprojection setting in Flight Simulator VR settings doing (“Depth and Motion”)?
A: Short answer: it does nothing today.
Long answer: it implements something called application-assisted motion reprojection, also called AppSW by Oculus. It requires your OpenXR runtime to implement a feature called XR_FB_space_wrap, which as of today, no runtime implements (not even the Oculus one - the only implementation of AppSW today is for native Android apps running on the Quest 2). When/if this feature is implemented by vendors, it will allow MSFS to pass its own motion vectors (computed during rendering for TAA, DLSS, motion blur etc) to the motion reprojection process. This will allow to 1) remove the need for motion estimation (which is mostly done on the video encoder anyway, so it will not affect performance dramatically) 2) use high-quality motion vectors for motion propagation (which can increase quality).
The “Depth”-only setting enables the game to pass depth information which is used on WMR for better spatial reprojection (when motion reprojection is off - this setting has no effect when motion reprojection is used). I can’t speak for other vendors, but I suspect they can also do better spatial reprojection with this setting. As for Oculus, I have not verified this information, but the claim is that depth information will also enable ASW 2.0 if you use motion reprojection.
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