TrackIR Stutter in DCS 2.8 at framerates other than 60 and 120 fps

[jillian.smythe]

Hello hughlb,

I appreciate your patience. One of our software engineers just provided some additional information. He says you are "right in that TrackIR polls at 120hz. It is really up to the developers and game engines to make sure that they retrieve the data at the right time and smooth out any stuttering that is a result of not being in sync. TrackIR does attempt some smoothing, but again, only reports that same data 120 times a second. If the game is out of sync, you will see periods of time where the game and TrackIR line up, and periods of time where it does not. This results in multiple frames in a row receiving the same data, and some frames even being lost. The jumping/acceleration the user observes is likely the game engine not polling at the right rate with his configuration. This is especially a problem if the game is depending on the framerate to poll TrackIR information. It should be its own process independent of framerate. I also see games often do their own smoothing for other input sources so that this is less noticeable if anything goes out of sync."

He also say that based on what you have said, "at some point windows full screen fixed this and made sure that the game was in sync and was receiving the right messages from TrackIR at the right times, and perhaps the game devs even programmed the game with the assumption this would not change." Windows and graphics card drivers have changed a lot since the TrackIR and DCS were first created, so if they made this assumption, it would not be surprising that there may be issues such as this.

The software engineer also asks if you have "any Microsoft products running in the background like Teams. He also mentioned that if your hard drive is near capacity, this could also contribute to the stuttering. He asked that I share this Reddit post with you to see if it helps:
https://www.reddit.com/r/hoggit/comment ... nd_system/

Kind Regards,

[hughlb]

Hi Jillian, thanks again for your response and investigation.

It is really up to the developers and game engines to make sure that they retrieve the data at the right time and smooth out any stuttering that is a result of not being in sync.

This is really critical information, and something I feel developers, such as Eagle Dynamics, should be better alerted to by NaturalPoint. FYI, I have a lengthy troubleshooting thread on both the Eagle Dynamics forum, and through an open support ticket. Almost everything has been suggested with the exception of recognition that this may be an in-engine issue in how the tracking data is retrieved and, consequently, smoothed.

at some point windows full screen fixed this and made sure that the game was in sync and was receiving the right messages from TrackIR at the right times, and perhaps the game devs even programmed the game with the assumption this would not change.

Again, really critical information for developers. They may be implementing TrackIR support without fully understanding how to manage its data, and circumvent this stuttering issue.

any Microsoft products running in the background like Teams. He also mentioned that if your hard drive is near capacity, this could also contribute to the stuttering. He asked that I share this Reddit post with you to see if it helps:
https://www.reddit.com/r/hoggit/comment ... nd_system/

Again, no change after looking into these suggestions. I think we can, at this point, assume the issue is a TrackIR polling rate, frame rate interaction, and how that is handled by the game engine. The only "fix" to this issue we have come across, is switching game engines. MSFS can have a variable framerate, as can IL2 Great Battles, without causing this stuttering problem, or at least minimizes it significantly. However, DCS is severely hampered by stuttering at framerates outside of a fixed 120 or 60 fps. The fact also, that for several years, and prior to their current 2.8/2.9 versions, they had resolved this issue (perhaps inadvertently), again support that this isn't a user issue with hardware or software conflicts and settings.

I will update my ticket with Eagle Dynamics and make these suggestions, but it would be useful if NaturalPoint could reach out and alert ED to the fact this issue can be both triggered, but also resolved by the developer. They might then look at how they can smooth TrackIR input data, perhaps even review previous versions where the issue wasn't apparent.

[hughlb]

Hi Jillian,

I have been in contact with Eagle Dynamics, and upon inspection of my dxdiag, they noted a number of BEX events involving TrackIR, can you clarify if this may be causing the stuttering issue? I have attached my dxdiag, and below is the message from Eagle Dynamics:

"Hey Hugh,

looking at your DXDiag I see a lot of these events:

Windows Error Reporting:
+++ WER0 +++:
Fault bucket 116150394282, type 5
Event Name: BEX
Response: Not available
Cab Id: 0

Problem signature:
P1: TrackIR5.exe
P2: 5.4.2.27545
P3: 570588ce
P4: TIRViews.dll
P5: 3.3.39.0
P6: 52e96a5d
P7: 00005bd2
P8: c0000005
P9: 00000008
P10: "

[jillian.smythe]

Hello hughlb,

If they haven't already, would you please ask Eagle Dynamics to review our latest SDK documentation? I did pass along the error you provided to our developers, but they don't think this related to the stuttering. Do you have this issue with any other games or simulators, or is it limited to DCS?

Kind Regards,

[hughlb]

Hi Jillian, I have passed on your message to Eagle Dynamics, now awaiting a response. On the BEX issue, it seems to be the only error in the dxdiag, and it came up a number of times - any idea of what it is? Even if unrelated to the stutter issue.

To answer your question, the issue is limited to DCS. MSFS and IL2 GB both don't have the issue, or the issue is minimized the point of being unnoticeable.TrackIR is smooth at variable framerates. However, with MSFS, I did need to enable both vsync and gsync to remove the issue. With IL2 GB, no changes were necessary. Although I do tend to cap framerates to 100 FPS, to match my 100 Hz monitor.

[jillian.smythe]

Hello Hugh,

I believe TIRViews.dll is only used by certain games. You could try renaming it temporarily to see if the BEX errors stop.

Kind Regards,

[Kurtosis]

Sorry to bring the bad news, but nothing will fix this issue besides capping your framerate to either 30, 40, 60, 120 FPS, etc As long as it either divides or multiplies 120 with an integer number. And of course you need to maintain that frame rate as closely as possible. So for DCS, 60 FPS is probably the best choice.

Otherwise the syncing issue, as reported by their software engineer, will make things appear unsmooth.

Best approach is to use the NVIDIA or AMD driver level frame rate limiters.

[hughlb]

Sorry to bring the bad news, but nothing will fix this issue besides capping your framerate to either 30, 40, 60, 120 FPS

This isn't true - I have a different experience depending on the application. For instance, In both IL-2 Great Battles and Microsoft Flight Simulator, this issue is not as apparent. It is significantly worse in DCS. This, in combination with the feedback from NP, suggest a form of smoothing within each title may be mitigating the issue. But I don't think it is a simple as this, as DCS has never had a smoothing option, and this problem was resolved for me prior to 2.8, for several years. So whilst I agree, setting it to 60 or 120 immediately resolves this issue in all titles, it is not the only solution to the problem.