OpenXR motion reprojection

[kurtz667]

Hi,

With the motiion reprojection disabled in openxr i get like 50+fps but movement in the cockpit stutters a bit.

When i put this option on "always on" i get like 30 fps with no stutters, but is there anyway to change it to 45 fps like in steamVR?

Thanks in advance! :)

 

 

[Sirbum]

i believe in open xr if you are not able to hold at least 65 FPS it will auto revert to 30 FPS with motion reprojection. So in order to keep 45 you would have to be able to hold above 70 i think it is. There is a post somewhere on the fourms of a test a guy did and what you have to hold consistently in order for it to hold 30, 45, 60 FPS with motion reprojection

[kurtz667]

Ok, makes sense.

Thank you!

[edmuss]

2 hours ago, Sirbum said:

i believe in open xr if you are not able to hold at least 65 FPS it will auto revert to 30 FPS with motion reprojection. So in order to keep 45 you would have to be able to hold above 70 i think it is. There is a post somewhere on the fourms of a test a guy did and what you have to hold consistently in order for it to hold 30, 45, 60 FPS with motion reprojection

This isn't quite right, there is a GPU overhead associated with reprojection, typically about 3-4ms on my machine if I turn it on.

To achieve 45fps reprojection you need to add your appGPU frametime to those overhead and the resulting total needs to be less than the 22ms needed to hold 45fps.

Therefore assuming 4ms overhead you need your appGPU to be <18ms otherwise it will drop to the 1/3rd refresh rate bracket (30hz).

edit: 18ms is 55fps so your 50fps likely isn't enough to consistently hold the 45hz reprojection. Running at 30hz isn't actually bad, you're still getting the same smooth performance but you might see more artifacts (this is very hard to quantify).

Edited March 23, 2023 by edmuss

[kurtz667]

Thanks for the clarification.

I just found out that with the ingame openXR toolkit trainer (ctrl +F2), you're able to choose between different fps for motion reprojection

Although when i choose 45 fps.

The ingame fps will be around 40, and not smooth at all.

So yeah i'll stick with 30 fps

 

Edited March 23, 2023 by kurtz667

[edmuss]

If you force a reprojection rate and you don't have the horsepower to sustain the required frametime (18ms or so for 45hz) then it will disable the reprojection. Better to leave it unlocked so that it can drop to 30hz. Steamvr is unable to reproject at 30hz so openxr provides a massive advantage for lower level hardware.

In my hundreds of hours of testing I've seen very little difference in artifact amount between 45hz and 30hz.

[wormeaten]

If I set Quest 2 to 120Hz is that mean will be working on 40Hz (1/3 of 120)? 

[VirusAM]

On 3/26/2023 at 5:53 PM, wormeaten said:

If I set Quest 2 to 120Hz is that mean will be working on 40Hz (1/3 of 120)? 

yes, but oculus has its own reprojection tech (ASW), it is however equally capable of deliver 1/2, 2/3 or 3/4 of syntethic frames per second.

Also steamVR is cabaple of that but only with the Valve Index (not sure about HTC vive series)

Edited March 30, 2023 by VirusAM

[actually_fred]

Just to clarify: there is no such thing as 'OpenXR Motion Reprojection'; there is WMR motion reprojection, which confusingly can be enabled from OpenXR Tools for Windows Mixed Reality, or OpenXR Toolkit - but it is part of WMR, not OpenXR.

For WMR DCS players, it can look like an OpenXR thing both because of where the settings are, and because when using SteamVR, SteamVR motion reprojection is used instead of WMR motion reprojection. It has no effect whatsoever on other headsets. Some other manufacturers have similar technology (like Oculus ASW).

I'm being pedantic here as there is a huge amount of content talking about 'OpenXR' features which are written by G2 users, is WMR-specific, and is very confusing to others because it doesn't apply to Pixmax/Varjo/Oculus/... even when using OpenXR.

Edited April 2, 2023 by actually_fred

[Rifter]

2 hours ago, actually_fred said:

For WMR DCS players, it can look like an OpenXR thing both because of where the settings are, and because when using SteamVR, SteamVR motion reprojection is used instead of WMR motion reprojection. It has no effect whatsoever on other headsets. Some other manufacturers have similar technology (like Oculus ASW).

To be even more pedantic: SteamVR motion reprojection cannot be used on anything else than Vive and Index devices. WMR VR headsets cannot be run with SteamVR in terms of a WMR replacement - they can only use SteamVR as a frontend to make use of WMR functionalities and to allow a per-application control setting. Motion reprojection itself will just be handed over to WMR.

There is an unbelievable amount of placebo effect user reports on the forum like ‘when I use SteamVR motion reprojection on my WMR device it runs better/smoother’.

 

[Temetre]

vor 7 Stunden schrieb actually_fred:

Just to clarify: there is no such thing as 'OpenXR Motion Reprojection'; there is WMR motion reprojection, which confusingly can be enabled from OpenXR Tools for Windows Mixed Reality, or OpenXR Toolkit - but it is part of WMR, not OpenXR.

For WMR DCS players, it can look like an OpenXR thing both because of where the settings are, and because when using SteamVR, SteamVR motion reprojection is used instead of WMR motion reprojection. It has no effect whatsoever on other headsets. Some other manufacturers have similar technology (like Oculus ASW).

I'm being pedantic here as there is a huge amount of content talking about 'OpenXR' features which are written by G2 users, is WMR-specific, and is very confusing to others because it doesn't apply to Pixmax/Varjo/Oculus/... even when using OpenXR.

Thank you. Im new to VR and its really difficult to find any accurate information about a lot of this tech. Even the most basic stuff.

So if I understand correctly, when Im using a Pico 4, is SteamVR not using any kind of motion reprojection? I suppose the reprojection is the ASW I can switch on in the Picos streaming software?

Edited April 2, 2023 by Temetre

[Mars Exulte]

9 hours ago, actually_fred said:

Stuff

 

7 hours ago, Rifter said:

More stuff

That would explain why they always seemed the same to me, I reckon.

[Chaos_Out]

On 4/2/2023 at 10:41 AM, Rifter said:

To be even more pedantic: SteamVR motion reprojection cannot be used on anything else than Vive and Index devices. WMR VR headsets cannot be run with SteamVR in terms of a WMR replacement - they can only use SteamVR as a frontend to make use of WMR functionalities and to allow a per-application control setting. Motion reprojection itself will just be handed over to WMR.

There is an unbelievable amount of placebo effect user reports on the forum like ‘when I use SteamVR motion reprojection on my WMR device it runs better/smoother’.

 

I wouldn't call it placebo, when most of those user reports are simply "I use steamVR, no stutter, when I use OpenXR, massive stutter."  I'm one of those that thought using SteamVR with a G2 made one use the SteamVR motion reprojection.  I can say for 100% fact that going from SteamVR to openXR, while mimicking the SteamVR settings and optimization mods as best as possible, the motion reprojection and performance IS worse, in both clarity and stuttering, for me and others on here (yes, used openxr toolkit).  I have better performance in single thread DCS using SteamVR than I do in multi-thread openxr dcs.  I have a 5900X and 3090.

[Rifter]

14 hours ago, Chaos_Out said:

I wouldn't call it placebo, when most of those user reports are simply "I use steamVR, no stutter, when I use OpenXR, massive stutter."  I'm one of those that thought using SteamVR with a G2 made one use the SteamVR motion reprojection.  I can say for 100% fact that going from SteamVR to openXR, while mimicking the SteamVR settings and optimization mods as best as possible, the motion reprojection and performance IS worse, in both clarity and stuttering, for me and others on here (yes, used openxr toolkit).  I have better performance in single thread DCS using SteamVR than I do in multi-thread openxr dcs.  I have a 5900X and 3090.

Motion reprojection (asynchronous space warp, etc.) is respectively the proprietary implementation of the different VR device manufacturers. It runs fully within the VR software.

The motion reprojection of SteamVR cannot be used as an alternative to WMR reprojection on a WMR device. If someone thinks otherwise, I’m looking forward with great expectation to the technical explanation for that.

Also I’m not aware of the fact that OpenXR Toolkit delivers its ‘own’ motion reprojection implementation as an alternative to the native motion reprojection of WMR. Even the dev of OpenXR Toolkit (mbucchia) was perplexed by the user reports about different behaviours (ghosting, stuttering, ...). OpenXR Toolkit just sets a registry key that enables the setting from OpenXR Tools for motion reprojection in WMR.

If anyone experiences differences in motion reprojection depending on his settings back and forth (SteamVR - WMR - OpenXR - whatever) that is a pure coincidence or something else (probably some other mess on his machine).

[Mk1_Trebuchet]

Just trying to wrap my head around which actors are responsible for Motion Reprojection.   I have a G2 and have been running OpenXR (Forced in the DCS Shortcut - No Steam whatsoever).  I use OpenXR Toolkit to enable (ON) Motion reprojection (unlocked frames).  It works pretty well, I get a decent and smooth experience at 45 FPS (jumping to 90 in open skies). 

As an experiment, I disabled OpenXR Toolkit and installed the Windows version of OpenXR tools... and forced ON Motion Reprojection. With no other changes, I got about 10 glorious minutes of super smooth, 90fps at ground level with very minimal, but still noticeable MR artifacts.  About 10 minutes into the flight, DCS hard crashed.  And since then, I get a hard DCS crash every time I try to run it with the Windows Tools and MR forced on.... reverting back to OpenXR Toolkit, I can force MR on with no issue (FSR or NIS selected) but the frame rate is back down to 45 (acceptable) and there is slightly more noticeable MR artifacts.

So if it is just WMR reprojection being used by OpenXR Tooklit and OpenXR Tools... where is the hard crash behavior likely coming from? (Seriously, I'm curious because I'm pretty sure I don't fully understand which components/software is responsible for which functions)

 

 

[freehand]

2 hours ago, Rifter said:

 

If anyone experiences differences in motion reprojection depending on his settings back and forth (SteamVR - WMR - OpenXR - whatever) that is a pure coincidence or something else (probably some other mess on his machine).

lol kidding right ? it's is known fact the G2 in vr using Openxr is a wobbling mess compared to steamVR but Openxr is still preferable because of other benefits 

Edited April 4, 2023 by freehand

[GCDV31]

@Mk1_Trebuchet same here with Reverb G2 DCS open beta. If Reprojection is ON in "OpenXR tools for WMR" DCS craches. If reprojection in OFF in "OpenXR tools for WMR" and ON in OpenXR toolkit no problem. Before last Update I used SteamVR because reprojection is bettre from my point of wiev I hope in next update we can choose Open XR or not.

[Mk1_Trebuchet]

@GCDV31 You can still choose whether to run OpenXR natively or through Steam.  Just open Steam VR and go to SETTINGS --> DEVELOPER and choose "SteamVR as the OpenXR Runtime"

 

I'm seeing some VERY curious results as I've been experimenting with all these setting options.  I'm truly not sure what is happening.   

For reference, I've been running the Native OpenXR and XR-Toolkit for as long as it's been an option. (Used Opencomposite before that)

Last night I changed over to Steam as the OpenXR Runtime - in the SteamVR settings, adjusted the scaling to 80%, and Turned ON Motion Smoothing.... unintentionally leaving OpenXR toolkit active.... and POW - 90Fps, clear as a bell with zero frame drop, and less than 1.5% reprojection.   Then I disabled OpenXR Toolkit.... 50-70 Fps Fluctuating and dropping frames - a total mess.  Re-enable the toolkit - Back to 90Fps....  (Not other changes or reboots, just restarted DCS)

I have had Toolkit also set to 80% and MR on via NIS... So I was intending to mimic those settings in SteamVR.

So is it that the Steam version of OpenXR is that much better?  is my system scaling the render stream twice? (80% x 80%) ...and somehow making the visuals FASTER and CLEARER?

I just can't wrap my head around the logical flow here.

(edited for spelling due to low caffeine levels)

 

 

 

Edited April 5, 2023 by Mk1_Trebuchet

[Rifter]

21 hours ago, freehand said:

lol kidding right ? it's is known fact the G2 in vr using Openxr is a wobbling mess compared to steamVR but Openxr is still preferable because of other benefits

I have no doubts about your specific experience - I’m very well aware of the fact that some people observe severe problems here.

But that has nothing to do with the usage of a ‘good working version’ of motion reprojection versus a ‘not so good working version’.

There is a big misconception that motion reprojection is something which can be changed by the user or applied as an alternative. As a G2 user you only have the opportunity to use the WMR version of motion reprojection. SteamVR motion reprojection works only for Vive and Index. Asynchronous Space Warp only applies to Oculus/Meta. And OpenXR Toolkit has no motion reprojection solution to offer at all. Selecting the option motion reprojection for a G2 in SteamVR or OpenXR Toolkit does not - surprise, surprise - select a specific motion reprojection variant. It just tells WMR to switch on its motion reprojection. SteamVR and OpenXR Toolkit only act as a frontend to the WMR Runtime.

I have different VR headsets and therefore always edit the windows registry for the desired VR runtime.
This can also be done by a tool: https://github.com/WaGi-Coding/OpenXR-Runtime-Switcher
It does nothing else than setting the registry to the selected VR runtime.

Never experienced any ‘wobbling mess’ with my G2 *). Never experienced differences in motion reprojection quality no matter in which tool I switch it on.

I want to apologize for my wording ‘placebo effect’. I did not want to offend anyone. I know that VR can be a pain in the <profanity>. But it is of no help when problems are broken down to the wrong causes. That just creates esoteric and snake oil solutions.

 

*) I tested a 6900 XT some time ago. That created a wobbling mess for all of my VR headsets when using motion reprojection. But that is due to the fact that AMD cards are not so suitable for that specific VR functionality. No problems with my 3090 at all.

[Baldrick33]

In my experience with my hardware after quite a lot of back to back testing there is a distinct difference between using the Mixed Reality OpenXR runtime vs the SteamVR OpenXR runtime. The latter is smoother and has less artefacts. I can also run motion reprojection without the OpenXR toolkit only with the SteamVR OpenXR runtime, otherwise I need the fix in the toolkit to run WMR OpenXR runtime. WMR runtime will drop to 30 or 22fps, SteamVR runtime is limited to 45. They are quite different experiences. 

[freehand]

2 hours ago, Rifter said:

I have no doubts about your specific experience - I’m very well aware of the fact that some people observe severe problems here.

But that has nothing to do with the usage of a ‘good working version’ of motion reprojection versus a ‘not so good working version’.

There is a big misconception that motion reprojection is something which can be changed by the user or applied as an alternative. As a G2 user you only have the opportunity to use the WMR version of motion reprojection. SteamVR motion reprojection works only for Vive and Index. Asynchronous Space Warp only applies to Oculus/Meta. And OpenXR Toolkit has no motion reprojection solution to offer at all. Selecting the option motion reprojection for a G2 in SteamVR or OpenXR Toolkit does not - surprise, surprise - select a specific motion reprojection variant. It just tells WMR to switch on its motion reprojection. SteamVR and OpenXR Toolkit only act as a frontend to the WMR Runtime.

I have different VR headsets and therefore always edit the windows registry for the desired VR runtime.
This can also be done by a tool: https://github.com/WaGi-Coding/OpenXR-Runtime-Switcher
It does nothing else than setting the registry to the selected VR runtime.

Never experienced any ‘wobbling mess’ with my G2 *). Never experienced differences in motion reprojection quality no matter in which tool I switch it on.

I want to apologize for my wording ‘placebo effect’. I did not want to offend anyone. I know that VR can be a pain in the <profanity>. But it is of no help when problems are broken down to the wrong causes. That just creates esoteric and snake oil solutions.

 

*) I tested a 6900 XT some time ago. That created a wobbling mess for all of my VR headsets when using motion reprojection. But that is due to the fact that AMD cards are not so suitable for that specific VR functionality. No problems with my 3090 at all.

So the rotor blades on the apache has no wobble in front of your view ? this is news to me.

Edited April 5, 2023 by freehand

[Mk1_Trebuchet]

Thanks for the clarification Rifter, the pieces are starting to come together.  I read the in-depth MR explanation that mbucchia posted in the MSFS forums (I believe you linked to it in another thread) and that was dense but helpful.    MR Explanation

As I'm understanding it, there is no 'tweaking' any of the MR variants, just on/off, and the performance of MR is dictated by what it is given, and how it's programmed to employ.  So your individual experience with it will be dictated by the system and settings you have.  (And the more MR interpretation frames your system generates and relies on to hit your fps goal, the more wobbly artifacts you will see.)

If Steam VR and OpenXR Toolkit have MR 'on'... it won't matter because they are both just turning the feature on. (correct?) But the Runtimes (SteamVR for OpenXR or Native OpenXR) each have their own MR code and may produce different performances on different systems (VR ecosystems) but it's still just on/off. (?)

In the Toolkit, is there a difference between choosing FSR or NIS with MR?

[Rifter]

2 hours ago, Mk1_Trebuchet said:

As I'm understanding it, there is no 'tweaking' any of the MR variants, just on/off, and the performance of MR is dictated by what it is given, and how it's programmed to employ.  So your individual experience with it will be dictated by the system and settings you have.  (And the more MR interpretation frames your system generates and relies on to hit your fps goal, the more wobbly artifacts you will see.)

If Steam VR and OpenXR Toolkit have MR 'on'... it won't matter because they are both just turning the feature on. (correct?) But the Runtimes (SteamVR for OpenXR or Native OpenXR) each have their own MR code and may produce different performances on different systems (VR ecosystems) but it's still just on/off. (?)

In the Toolkit, is there a difference between choosing FSR or NIS with MR?

Every VR ecosystem has its own implementation of motion reprojection - it is part of their IP. There is no cross-usage of those implementations possible. One would have to reverse engineer a VR system to do that.

Motion reprojection can be set to permanently on/off or can be set to be activated when a certain amount of fps is not reached. Those settings can also be set outside of a VR ecosystems (in SteamVR or OpenXR Toolkit) - which obviously confuses a lot of people.

Historically DCS supported OpenVR (SteamVR) and LibOVR (Oculus). DCS never supported WMR so there was no other way to use a WMR Headset (like a G2) than via SteamVR. That had always being a pain because the WMR plugin for SteamVR was not a masterpiece performance wise. It was a kind of ‘lost in translation’ thing.

With DCS now supporting OpenXR all of that should be history because all VR ecosystems have OpenXR implemented and can now be run native by DCS. So if motion reprojection on a G2 performs better with SteamVR (OpenXR) than with WMR (OpenXR), there must be something wrong with the OpenXR API implementation on the WMR side.

It would actually mean that the chain
DCS —> OpenXR —> SteamVR (WMR OpenXR) —> WMR motion reprojection ( = OpenXR via SteamVR as a fallback)
works better than
DCS —> OpenXR —> WMR (OpenXR) —> WMR motion reprojection (= native WMR OpenXR path)

Hence on a WMR device there is no
DCS —> OpenXR —> SteamVR (OpenXR) —> SteamVR motion reprojection

The up-scaling technologies FSR and NIS have nothing to do with motion reprojection - they can be used according to your own taste and you can always decide to use motion reprojection on top of that.

[Joe1978]

I have the same experience that Mk1_Trebuchet, Baldrick33 and GCDV31 with my HP Reverb.

hace 16 horas, GCDV31 dijo:

...If reprojection in OFF in "OpenXR tools for WMR" and ON in OpenXR toolkit no problem. Before last Update I used SteamVR because reprojection is bettre from my point of wiev.

Even so, with this last option, I still have some artifacts... although I can live with them, I prefer SteamVr too. 

 

[mbucchia]

Patience folks... there should be some good news coming in the next couple of weeks.