Choppy Trackir View with Vsync off on 60hz monitor

[Ram69]

[Raven434th]

I use trackIR as well, Are you using an SSD or HDD??   if HDD try optimize defragging your DCS folder ,I do this with every patch and it gets me smooth no stutter game play(this does NOT however fix FPS issues, that's a different animal.)

Edited November 29, 2021 by Raven434th

[Bossco82]

Well I am not gonna join in any Track IR based argument. Its only going to get in the way of Ram69 solving his problem. Ram69 if you continue to have a problem running DCS in any way mate please feel free to drop me a pm for any ideas that might solve whatever problem that might be. Take it easy all.

[scampaboy]

Can I throw a spanner among the pidgeons ? 
 

I suffer a lot from shimmer and I was thinking about why and one of the hypothetical nonsense ideas I came up with was the electrifying electric chair issue. 
 

For example in the UK and the USA we both use a different frequency of electricity. I can’t remember which frequency is where but if you used a video camera for a market with a different frequency and weren’t able to adjust the shitter speed you would get severe shimmering and aliasing on lines in the video. Early American iPhones suffered from this in Europe etc. 

just throwing a pidgeon in the works but maybe it’s related to this problem. The track ir sensor is a camera after all and we can’t really do much with the shutter speed. Maybe that’s what’s causing the stutter. 

[SharpeXB]

All your peripherals can change the view on the screen. Even your keyboard. None of those are synced to the screen refresh rate. You can pan your view right and left with the A and D keys, does that cause a stutter? I think the deal with head tracking is that it makes any stutter or tearing more noticeable but it’s not causing the effect. 

[Raven434th]

My suspicion is it has to do with how and how fast the data on the drive is being accessed that's causing stutter. In my case on an HDD I always have to defrag and optimize the installation folder or it stutters...I also noticed if I switch to maps/missions that I don't normally use...it stutters...then I defrag and optimize then  the stutter goes away. How this may apply to a SSD I do not know. Keep in mind this is all speculation and something entirely different may be going on, it's just what I perceive to be the cause. Again I use track IR on a 22 inch monitor@60hz and get smooth game play at anything above 24 fps...when it drops below 24 (and It does a lot of the time) ,is when I see the slow down(not to be confused with Stutter)

[silverdevil]

On 12/6/2021 at 1:09 PM, scampaboy said:

Can I throw a spanner among the pidgeons ? 

######

For example in the UK and the USA we both use a different frequency of electricity. 

LOL. "Blasted pidgeons" Good point. I know a UPS helps this effect. There are line conditioners too.

[scampaboy]

3 hours ago, silverdevil said:

LOL. "Blasted pidgeons" Good point. I know a UPS helps this effect. There are line conditioners too.

I don’t know what line conditioners and UPS are. It was just a mad theory I had about shimmer and stutter. 
I’m  wondering apart from the option of 60 and 120 are there any other frequencies we could use, I know in my track hat software it’s either 60 or 120 maybe there is a config file that could be edited. 

Edited December 8, 2021 by scampaboy
Bad spelling

[Py]

3 hours ago, scampaboy said:

I don’t know what line conditioners and UPS are. It was just a mad theory I had about shimmer and stutter. 
I’m  wondering apart from the option of 60 and 120 are there any other frequencies we could use, I know in my track hat software it’s either 60 or 120 maybe there is a config file that could be edited. 

 

60/120 FPS are US-centric framerates, in countries with 50 Hz power cameras should run at 50/100 FPS for consistent brightness when using mains-powered lighting.

That doesn't apply to trackIR though, as it provides it's own IR lighting (with no flicker).

It does seem likely that the asynchronous updates of camera position from trackIR vs frame render time are causing stuttering, as smooth head motion is being chopped up into uneven steps for display. Locking display refresh rate to 60/120 Hz *should* fix it, if that's the only cause, but it shouldn't be necessary and removes the benefit of g-sync etc.

I can think of two ways to fix it properly, one by naturalpoint (doubt they will bother), and one by ED:

1. Change trackIR position reporting from a fixed rate set by the camera, to a request from the user (eg from DCS). The software already does motion smoothing so should be able to give interpolated/extrapolated position at the exact render time, eliminating uneven motion even if the frame rate is varying.

2. DCS could get the polled 120 Hz data and do it's own motion smoothing/estimation, then use the position estimated at the time of render. That would probably need to be done in a separate thread, but would be pretty simple to do. ED already has a huge TODO list, but if this feature can be added to the new multi-threaded engine they are working on it *should* solve the issue.

I think this isn't a problem for VR because steamVR etc is already doing the motion smoothing and extrapolation of position data before providing it to DCS.

[Ram69]

I've spent far too much time digging into this. I'm less convinced it's actually a trackir-specific thing. As someone else mentioned, I'm more thinking now that it's just exacerbated by Trackir. 

 

What I think is more likely going on is something to do with vsync being off and/or slipping from a perfect 60fps. I managed to create a situation a few times through jacking settings higher and an actual mission with AI where my fps got locked down to 30 a few times. Interestingly, 30 was actually a smoother experience than 50. 50 (and pretty much anything under or over 60) feels more like about 15. 

 

30 feels like 30, but only sometimes. Locking my fps to 30 and/or going with half-refresh vsync doesn't consistently make it behave like 30. Even if it did, that's a pretty bad compromise. 

 

I don't know what's causing it. Tried many, many things, and read too many good and bad suggestions around the interwebz about it or that seemed adjacent to it. But, off of 60 (except sometimes with a perfect 30) or vsync off just behaves like 15fps or so. 

 

I happily played many games in the mid 40s in years past, so it's not just a situation of me being picky. Things just don't behave properly off of a perfect 60, for the most part. I do get higher frametime and more spikes when I'm off of that perfect 60. I'm sure it's related somehow. 

 

It's just not my historical experience at all that playing games off of 60 (with vsync on and a 60hz monitor) behaves so poorly where basically any other frame rate is essentially akin to playing at 15fps. 

 

Perhaps I'm just running into a situation where I'm a bit CPU bottlenecked once I add AI into the mix, due to the engine limitations of DCS on the multithreading front. Consequently, perhaps I'd experience this less with better per-thread performance. I don't think that fully explains why anything off of 60 is so poor in terms of "smoothness", however, as it's not at all representative of what 50 actually plays like, for example. But, I suppose my GPU waiting around for instructions from the CPU could cause the frametime degradation, and consequently the lettuce chopping experience. That still wouldn't explain why such a poor experience when playing at 70 or 100, however; only when falling below 60 in this case.

 

I'm not planning on a new CPU just yet. Waiting to see what 2022 brings on that front before considering an upgrade, and that would be an overkill of a "workaround" -- at best -- for this particular situation. 

 

50 is just a lot more likely once you throw ai and an actual mission into the mix. If it was 5% of the time, I wouldn't really care. But, it's more like 50% of the time when you're trying to do anything other than fly around, which is making it a bit untenable for me. 

 

Anyhoo, long post to basically say  Don't know why things behave so poorly off of a pure and steady 60, and the lettuce chopping is not representative of my historical experience of playing at 50, or 70, or 40 for that matter. Don't know why it's an issue now, when not in the past. The two variables between then and now would be playing DCS again for first time in about 5 or so years, and a 3080 bought about a year ago. 

Edited December 8, 2021 by Ram69

[Ram69]

Just fired up Star Citizen for the first time in a decent while. A game guaranteed to give you a sub-60 fps test bed  

 

Even at 26-35fps it was a considerably smoother experience with or without trackir. It was night and day different compared to even 50 in DCS. That's saying something when I can call Star Citizen smooth in comparison

 

So, DCS seems almost definitely to be part of the equation for this issue (whatever this issue is). Of course, Start citizen is using about half of my GPU memory and utilization, where DCS pretty much always likes to gobble all 10GB of my video memory. 

 

Star Citizen performs relative to its framerate, be it 30, 45, 70 or whatever, with Vsync on or off. DCS World, for some reason does not. It's seemingly the only variable here when I get the "lettuce chopping" off of a pure and steady 60 and/or with vsync off. I have no idea why, but it's a shame when 55 or 75 is pretty unplayable (on DCS) for me

Edited December 8, 2021 by Ram69

[Hiob]

I'm repeating myself here -

The framerate is not the cause for TrackIR-stuttering. That's a very simple prediction of a very simple theorie that can easily be falsified. Which it was. (among others, by yourself)

 

[Ram69]

Trackir doesn't appear to be the cause of stuttering either (for me). It just exacerbates it.

 

But something to do w dcs does, when fps is off of pure 60, either above or below that magical number. If it's 50, or 100, it is more like a slow motion, choppy mess.

 

Something that I'm not experiencing in other games currently or historically. 

 

Doesn't seem too likely to me at this point that there is an end-user cause or fix, since DCS is the only remaining variable from where I'm sitting. 

 

Trying to do anything and everything to maintain a perfect 60 (never above or below) is a workaround, imo, not a "fix". Going off of 60 is not the cause either (at least not outside of DCS). 

Edited December 8, 2021 by Ram69