Tweaking the HP Reverb

Hi !

Moving from a Pimax-thread to not get too OT there.

 

I keep hearing that 45fps looks great on the Reverb, with no ghosting or stuttering, but I sure did notice those two, even with the frame rate locked at 45fps (often going up to 60 in quiet areas).

If you have reprojection on, you should really only se 45 or 90 FPS, and for very short moments the calc could get in between when the FPS-calculator in DCS gets a average that contains some part time at 45 and some at 90fps. If I go to very dense areas of forrest that also has a lot of hills and mountains and do Quick turns and rolls at very low level I can see the counter just briefly leave 45 and show perhaps 43 for like one frame. Its possbile to not have this by lowering the grahpics but I tried to find the best sweet spot between performance and quality.

Asynchronous Reprojection must come with ghosting and stuttering. The HMD API has to "fake" every second frame, so these side-effects are present.

When I was answering the first few answers about stuttering, I came from around 3 years of Oculus Rift CV1 and DCS. With Oculus Rift you have to learn to accept stuttering and ghosting and most of the time tweaking is to try tyo make it as little as possible. It takes a lot of time to tweak oculus, but the reverb was way quicker( some come from being used to but most is the fpsVR-software). I hope you have used it, because it show you inside the VR headset in real time when you get stutter or ghosting, you also can se the reason.

Hi !

The vid is up. Remember that showing 45hz(fps) on a 60hz Viewer(Youtube video and your normal 2d display) newer vill come out smooth even if the source was smooth.

I did the same and took a screenshot from the video I produced on my phone showing 45fps over the buildings. It was a solid 45fps all through from take off to run over town.

The only thing I get ghosting with typically is other aircraft in dogfighting. buildings will only ghost and stutter if I drop below 45 which normally doesn't happen. That is at 100% supersampling. If I change this to 200% then I will get stutters and ghosting doing the F14 take off.

Yes as Baldrick says, 100% supersampling.

I Think its possible that we kick in some already open doors but to be sure...

The best idea is to start with at following the guide bu thud at vr4dcs.com: https://vr4dcs.com/2019/08/08/moving-from-oculus-to-reverb/

If you (GunSlingerAUS) keep seing a lot of stuttering we first must check that you actually did get motionreprojection working. Its in the guide, but what you have to do is take away those // in front of the string "motionReprojectionmode" : "auto", ( black marking in pic )

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Yoy cant test by removing the // for the motionreprojectionindicatorenabled". If you have success youll get a green or blue Square on top of the VR-headest Picture. Its supposed to help with tuning, but I Think fpsVR is a much better tool. To get rid of the indicator, just put the // back and save.

For the Supersampling. I could find a slightly sharper picture of increasing the SS to a higher value but my i9 9900KS+RTX2080ti cant handle this(maybe if lowering a lot of other settings.

You should not have pixeldensity set to anything else but 1.0 in DCS VR-settings. Pixeldensity does the same as supersampling in reverbs/steam settings but at a higher cost of performance.

The resulotion should be set to 100%(check that it equals resulotion 2207 x 2160).

Theres a lot of other settings, mainly covered in vr4dcs.com but those should be the one to check if you setup is ok to begin with.

Do you overclock the videocard ? I have an Asus RTX2080ti and I use the asus overclock tool. It give me around 10% extra GPU-Power which comes in very handy when playing DCS in VR.

Again, I cannot stress enough the importance of using fpsVR and in real time se what is the limiting factor and also seing how close the hardware is to their limits.

You guys are absolute bloody legends! Thank you so, so much for doing this, and taking the time to help me get to the bottom of this issue. It proves I'm not crazy! ;) Unfortunately screen shots won't show these problems, as it needs to capture in video to see this. I’m not sure if NVIDIA’s built-in video capture program will work for this, as it may rebuild the video one frame at a time. I’m not certain on this though.

Even though YouTube compresses the video, and in the process tries to smooth out judder, I can still see the stuttering in the F-14 take-off mission. If you're not sure what I mean when it comes to judder (also called stuttering), this explanation is a good one. Even though it is talking about 24fps playback on a 60Hz display, the end result is exactly the same.

Ghosting is very different, as this displays a weird shadow/ghost of fast moving objects that extend behind the object. You can see this effect clearly if you run the F-14 instant action dogfighting mission. Look at the Flanker as it passes to your right after the merge, and you'll see it looks bloody horrible.

If you guys could capture the F-14 instant action take-off mission again but in much higher quality and framerate, and this time look out the left side of your canopy as you’re turning left over the town at the left of the runway, you should see the problem. Looking straight ahead is quite smooth when it comes to ghosting/judder, as there aren’t many objects in the scene moving at high speed. But as soon as you look out the side of your canopy or start manoeuvring quickly, the ghosting shows up. Alas, this scenario is commonplace for fighter pilots. If we were flying boring airliners, we’d probably never notice, as you’d be constantly looking forward, and the speed isn’t high. This could be why ground-pounders don’t notice the issue quite as much.

I’ll pop up a video today of my experience, so we can do a direct comparison. Oh, and thank you for the offer of assistance, but as mentioned I’ve tried every thing known of to man, and then some. And triple thank you for helping me out. I'm sure many people will be helped by this information.

Here's a funny question: I run DCS non Steam version (not sure if relevant), and Windows Mixed Reality for SteamVR Beta, enabled the reprojection/indicator lines as per MS and all other instructions, and and reprojection is not working and the indicator is not shown.

Any ideas if it's related to the fact that I use non Steam DCS?

Here's a funny question: I run DCS non Steam version (not sure if relevant), and Windows Mixed Reality for SteamVR Beta, enabled the reprojection/indicator lines as per MS and all other instructions, and and reprojection is not working and the indicator is not shown.

 

 

Any ideas if it's related to the fact that I use non Steam DCS?

I'm on non-Steam DCS with my Reverb, and reprojection works just fine. When I have the indicator turned on though, sometimes I have to pull the HMD up a little on my face to see it.

 

If you guys could capture the F-14 instant action take-off mission again but in much higher quality and framerate,

I think this is where we're having our collective communication breakdown on this never-ending subject. If we go to much higher quality, we're going to get the same results you're getting. That's why we're not going there. What is the point of exceeding the known, current limitations of the system? Its not a direct, apples-to-apples comparison if you're doing that and the rest of us aren't.

I'm on non-Steam DCS with my Reverb, and reprojection works just fine. When I have the indicator turned on though, sometimes I have to pull the HMD up a little on my face to see it.

Ok good to know. It just flat out refuses to work here and to show the indicator no matter how I move the headset.

The config:

{
   "driver_Holographic" : {
   },
   "driver_Holographic_Experimental" : {
       // Motion reprojection doubles framerate through motion vector extrapolation 
       //     motionvector = force application to always run at half framerate with motion vector reprojection
       //     auto         = automatically use motion reprojection when the application can not maintain native framerate
        "motionReprojectionMode" : "auto",

       // Automatic motion reprojection indicator to display the mode currently selected
framerate
        "motionReprojectionIndicatorEnabled" : true,
   
       // Motion indicator size and position in 0-1 space
       "motionReprojectionIndicatorSize" : 0.05,
       "motionReprojectionIndicatorXPosition" : 0.3125,
       "motionReprojectionIndicatorYPosition" : 0.3125,
       
       // Some people may experience increased discomfort such as nausea, motion sickness, dizziness,
       // disorientation, headache, fatigue, or eye strain when using thumbstick controls in Windows Mixed Reality.
       //
       // Setting thumbstickControlsMoveEnabled to true may cause application compatibility issues
       "thumbstickControlsTurnEnabled" : false, // true = use thumbsticks for artificial turn, false = default application thumbstick behavior
       "thumbstickControlsMoveEnabled" : false, // true = use thumbsticks for artificial move, false = default application thumbstick behavior
       "thumbstickControlsReversed" : false,
       "thumbstickTurnSmooth" : false,
       "thumbstickDeadzone" : 0.25,

       // During some transitions (typically entering Home), controller events start accumulate and the system has difficulties to catch up
       // Settings a mximum age for a contoller input allows ensuring that the events queue does not grow indefinitely
       "obsoleteStateMaxTimeInSeconds":  1.0,

       // Disable DX12 support
       "forceDisableDX12": false
   },
   "NoInterEyeRotation" : {
       "battlezone_dx11.exe" : true,
       "battlezone_dx12.exe" : true,
       "DOOMVFRx64.exe" : true,
       "Fallout4VR.exe" : true
   }
}

I think this is where we're having our collective communication breakdown on this never-ending subject. If we go to much higher quality, we're going to get the same results you're getting. That's why we're not going there. What is the point of exceeding the known, current limitations of the system? Its not a direct, apples-to-apples comparison if you're doing that and the rest of us aren't.

Sorry, I meant higher quality and resolution of the video recording. Apologies if I wasn’t clear, but I thought my reference to capturing at a higher framerate indicated I was talking about video.

Sorry, I meant higher quality and resolution of the video recording. Apologies if I wasn’t clear.

Ahhh...got it. :) It'll be interesting to see if that reveals anything, or if it shows things that aren't even there. You might be right about a direct recording re-constructing things, and the smartphone method might introduce all new variables by not quite syncing properly with the scan rate of the HMD.

Ok good to know. It just flat out refuses to work here and to show the indicator no matter how I move the headset.

 

 

That config all looks good. Just a question that I'm only asking because I got bitten by it myself: After you made the change to the file, did you shut everything down and restart? SteamVR for WMR only runs the config instructions when it is initially started. Just something I found out the hard way, and then kicked myself afterward for missing something that should have been obvious to me. :doh::D

Ahhh...got it. :) It'll be interesting to see if that reveals anything, or if it shows things that aren't even there. You might be right about a direct recording re-constructing things, and the smartphone method might introduce all new variables by not quite syncing properly with the scan rate of the HMD.

Provided the camera records at a higher framerate than 45fps, it won’t introduce new artefacts. From memory the recent phone cameras record at 60fps. This is how monitor testers check for motion blur on displays. The pros at rtings.com have some great examples, where they go into detail about how they do all of their testing. Best guys in the biz if you ask me!

:lol:

Provided the camera records at a higher framerate than 45fps, it won’t introduce new artefacts. From memory the recent phone cameras record at 60fps

The video is recorded with 60fps and 1080p/ 1920x1080. I Did cut down sides showing black instead of my desktop so its still 1920x1080x60hz.

I made a mistake letting Final Cut Pro send it directly to my youtubechannel without checking the compression settings. It didnt come out as sharp as I wanted. Ill do it again tonight.

The judder is what is was talking about before putting the vid’ out. All of this is introduced by filming at a different framerate than the source. Not e of this is seen in the VR-headset at all.

Your idea that recording at a higher frame rate doesnt introduce judder is not correct.

It can be done if filming with a multiple of the source, for example if source is 45fps then a 90 fps filming is ok. But 45fps source and 60fps filming will introduce a not perfect flow due to exactly the same reasons as in your link to the explanation, but there the source is 24fps and output 60 fps.( I am a home cinema nerd since 20 years with projector and HTPC and I am quite allergic to judder in TV and movies).

We cannot really overcome the judder from 45fps source when showing on a 60hz screen, even if I film it at 120 or 240fps.

It would be possible to set the reverb to 60fps, and when the computer is able to project 60fps it would be smooth but when comming down to 30fps with motionreprojection it will not flow that nice. No judder introduced because 60 is a multiple of 30 but I dont think 30fps is good enough and anyway, we cannot show reverb at the settings we are talking a out now.

Could I bug one of you to show a screencap of the reprojection indicator in DCS with your Reverb? I am trying to see exactly how it will look and where it will be in the game (and not just the MS doc)

Thanks in advance.

I wonder if my reprojection isn't working due to an older win10 version? HMMM (but sounds unlikely)

Could I bug one of you to show a screencap of the reprojection indicator in DCS with your Reverb? I am trying to see exactly how it will look and where it will be in the game (and not just the MS doc)

 

 

Thanks in advance.

 

 

I wonder if my reprojection isn't working due to an older win10 version? HMMM (but sounds unlikely)

Yep, no problems. This night!

Provided the camera records at a higher framerate than 45fps, it won’t introduce new artefacts. From memory the recent phone cameras record at 60fps. This is how monitor testers check for motion blur on displays. The pros at rtings.com have some great examples, where they go into detail about how they do all of their testing. Best guys in the biz if you ask me!

Simply matching scan rates isn't enough. They have to be synchronized or you get destructive interference which introduces recorded visual anomalies.

I took a Picture inside the Reverb for bn880 tonight, to show the motionreprojectorindicator.

Its quite clear that I wont manage to film the Picture inside the reverb with the Iphone X.

I have a gopro though, possible that it can be done in 120fps, and because the Youtube doesnt allow anything higher than 60hz it still cant be shown smooth. It would be possible to put the Movie in itself in for example a dropbox or something like that. With 120fps it would at least capture all 45 dual frames so I dont Think it would come upp with judder that you see.

If it is Worth the work, I dont know. I know that I have quite nice smooth gaming, and compared to the Oculus Rift it is much smoother.

.

Could you make a video of your stuttering and ghosting problems ?

I hope you run Pixeldensity 1.0 in DCS, and what resulotion do you run in Steam VR ? ( 100% 2207x2160 should be the one to begin with.

Also, do youm see either 90 or 45 fps, or do you se all other "free flowing numbers", like 73 and 55 and so on ?(thinking if you didnt get reprojection to work ?

Updated the same video, just new rendering with lot less compression:

The judder we see is the catching of 45 fps with a 60 fps recording. ( 60fps = 16.67ms and 45fps 22.22ms).

If we start both projecting and recording at the same time, after 4 frames of 60fps there has only been 3 frames and at frame 5 of 60fps, there will be recorded two frames of the same projected 45fps movie. This will create a non smooth video in 60fps, because the frames that is shot twice causes the movie to appear as ”frozen” during 1 frame. This will happen 45/4 times per sekond or roughly 10 times/second. This is also what we see in this movie.

Regarding the shooting of a 45fps image at 60fHz, won’t the only visual anomaly be screen tearing, and not judder (stuttering)? Or is that incorrect?

Will grab video now.

Updated the same video, just new rendering with lot less compression:

 

 

 

The judder we see is the catching of 45 fps with a 60 fps recording. ( 60fps = 16.67ms and 45fps 22.22ms).

 

If we start both projecting and recording at the same time, after 4 frames of 60fps there has only been 3 frames and at frame 5 of 60fps, there will be recorded two frames of the same projected 45fps movie. This will create a non smooth video in 60fps, because the frames that is shot twice causes the movie to appear as ”frozen” during 1 frame. This will happen 45/4 times per sekond or roughly 10 times/second. This is also what we see in this movie.

Just checking if your latest video used a through the lens capture? It doesn’t appear to.

Just checking if your latest video used a through the lens capture? It doesn’t appear to.

No, I wasnt able to take a descent shot. It either focused on the lens itself or nothing which made the movie useless.

I think I can maybe try with a gopro and shoot 120fps. That should be such hi fps that we not get disturbed by the unevenes comming from non matching frame rates. But to se it, it has to be the raw movie put for example on droxbox or another cloud service.

I didnt find any online movie serviceprovider that offers more than 60fps.

Im not sure it is worth the time( for me anyhow, already knowing I get a smooth experience for the most on REVERB+DCS).

I actually think discussing the settings you use on WMR, SteamVR etc. I think the problem is in that area.

What resulotion do you run for dcs ( steamVR)?

You should use the beta and 100%( it has to say resulotion 2207x2160) if you supersample it higher you most likely will not have smooth 45fps. This is because you bog down the GPU.

The small software fpsVR will show you very important info avout what it limiting or even close to limiting. For example when I can see the videocard RAM reaching 10.7Gb of 11 Gb possible I know that inreasing for example visibility range vill inrease the RAM, probably reach the limit.

Withput this software(4usd) I do not kniw what is limiting me.

Have you updated to windows 10 version 1909?

WMR updated ?

The thuds guide at vr4dcs.com tool me straight to nice flow. I only needed a couple of hours to get really good settings with the close to optimum setting with smooth 45 or 90 fps and high quality.

Regarding the shooting of a 45fps image at 60fHz, won’t the only visual anomaly be screen tearing, and not judder (stuttering)? Or is that incorrect?

 

Will grab video now.

No, tearing isnt a problem in this case. Tearing was very common in the home theather PC world earlier, the movie video renders had problems.

Basically, if the computer is in the process of rendering a a frame and during this process takes the unfinisched frame and tries to show it, it can end up in two different parts of pictures shown together.

Ive think Ive seen tearing in PC gaming also, but it was a long time ago and mostly when trying to do things the video card couldnt...in some cases maybe glitches in drivers etc.

In this case, both shooting via the lens with a camera or capture via the mvidia software, the whole frame will be shown. Id say the camera shutter time is way longer than the time it takes for the monitor to draw the complete picture, making each frame complete.

My lack of reprojection was indeed the windows version, I had 1803 and going to 1903 made the reprojection work right away.

I notice however a drop of 15% in raw FPS now in DCS (15% longer frametime), however with reprojection working things are looking bloody great now (smooth)!

Thanks for the help/tips.