Ghosting problem on Vive Pro 2

[SimoneSantillo]

Hi everyone, I hope I'm posting in the right place.

I'm working on a mixed reality project that runs at most at 30 FPS and I would like to render it on the HTC Vive Pro 2 at its original frame rate. I noted that the rendering in the HMD suffers from a "ghosting" effect when the user turns his head around. I suppose that the problem is caused by the "Motion Reprojection" (or Async Reprojection) that is done under-the-hood to maintain a 90 Hz framerate on the HMD. 

I could not find any way to disable this feature and allow me to render a (at most) 30 FPS video stream on the HMD.

 

Here's what I've tried up to now:

• Hit the Shift+A key binding in the SteamVR mirror screen
  • Any log is prompted in the developer console
• Click on the "async_mode_toggle" in the Debug Command window
  • I get the following log
  • But the console does not tell me if I toggled ON or OFF. Anyway, I repeated this process more than once to test either toggles.
• Given above points, I was not sure I was effectively disabling the reprojection, so I went to the VIVE Console -> Headset Mirror -> Mirror Mode -> Show Info and check the "Reprojection count" stat
  • Even if I (theoretically) disable the async mode from the Debug Command, the reprojection count still adds up, hence I'm not sure the disabling is effectively happening.

 

Additional information:

• Windows 10 latest update
• i9-11900K
• NVIDIA GeForce RTX 3080 Laptop (v511.65 drivers)
• 64 GB RAM
• DirectX 12

 

Am I right on thinking that the problem is the "Motion Reprojection"? If so, do you have any suggestion on how to disable it / effectively run an application at its real frame rate, i.e. without interpolated frames? 

Edited February 3, 2022 by SimoneSantillo