SkyboxVR stutter on 8K VR MKV - Win 10

x3style

Hi,
I would like to report a bug that happens with the latest version of the Meta Quest 3.

Context:
I started having stutter problems after i updated to the latest SkyBoxVR version as well as latest Meta Quest 3. While running SkyBox VR on the PC via Meta Link.
MetaQuest3: v83.1028 - Build 5156385.14650.520
SKYBOXVR: v1.1.8-2669

Replicate
It seems to occur after the PC has started for a while 30mins or more and seems to arbitrarily get fixed on reboot but not always.

Debugging steps
After checking everything else, bandwidth, connectivity, etc. I ended up with the conclusion that it must be running on some lower priority or performance mode.
I could replicate the behaviour on 2 completely separate machines/network setup. So it's related to either the device/drivers or the skybox vr software. And i tend to lean on the latter as other apps do not have this issue.

Workaround
So i started checking it out using task manager but it turned out that as soon as i open the Oculus_SourceVRPlayer.exe thread stack [that runs 2 executables underneath: SKYBOX and UnityCrashHandler64] in Task manager. Once i click on SKYBOX the app thread the whole app springs to life and starts performing as expected. This behaviour tells me that for some reasons although the window is active and in foreground it seems the app is started in some background priority mode for PC resources which throttles CPU and GPU resources.

If you can please investigate.

I hope this helps everyone else that might be having this issue, if i am having it on 2 completely separate PC's and locations then it must be affecting many others.

At least now i found a workaroudn that i hope helps everyone else until the root cause is found and fixed.

Best regards

Lucy

x3style
Hello,

Thanks so much for your detailed feedback!

We will do some tests to further look into the problem. To help us diagnose the issue more effectively, could you please share the app logs with us?

You just need to:

Click SKYBOX's "Global Settings", change the "Logging Levels" to "Info".
Reproduce the issue you mentioned.
Click the "BUG" icon in the upper-right corner of "Global Settings".
Tick the "upload logs" box, and submit the in-app feedback.

Thank you for your cooperation.

x3style

I've done what you asked and put this forum post link into the (Optional) Description for quick reference.

Lucy

x3style
Hello,

Thank you for sharing the logs.

We still need to investigate this issue further, and it may take some time. We will get back to you as soon as we have any new findings.

If you have the MPV player on your computer, could you please try playing this 8K VR video with MPV and see if it plays smoothly? Additionally, would you be able to share the particular video with us for testing? Thanks!

Best regards.
Lucy

x3style

Lucy
So i hope by MPV you meant https://mpv.io/. If that is the case i tried a windows build of it and it seemed to stutter as well on some videos.In this case it seems some of the videos stutter other don't and the task manager fix does not work.
It seems that decoding drops no frames but output drops frames which is where the stutter seems to come from.

Futher investigating into stutter steps turns out that if i add hwdec=auto to MPV's mpv.conf the stutters go away and the videos play perfectly.

This leads me to belive the player does not initiate HW decoding correctly on certain videos for some reason. This is clear from the very high CPU usage without the hwdec=auto configuration doing 60-80% CPU on all cores. dropping to 10% when hwdec=auto kicks in there is also a 4GB spike in GPU VRAM usage when hwdecoding actually functions.

Unfortunately i am unable to share the videos ....😅

x3style

Updated to:
MetaQuest3: v85.1028 - Build 5176473.12500.520 - updated
SKYBOXVR: v1.1.8-2669 - Same, latest

Problem persists in the same way. As soon as i open the task manager oculus entry the Hardware Acceleration kicks in and stays on for the session.

I even reinstalled Meta Link which received a new version -> Meta Horizon Link version 85.0.0.232.552
You can notice the wobbly logo interface as the app itself is loading as well.
Like 1-2 seconds before the screen goes blank and it loads the player interface.

x3style

I've done some more extensive testing turns out that some of the newer videos are of a slightly higher resolutions and they all consistently exhibit this issue it might help you reproduce it.

The 8192*4096 consistently lags unless I do the task manager trick, then it works fine. So for this the hardware acceleration does not automatically kick in.

The lower ress works fine.

Lucy

x3style
Hello, thank you for taking the time to share such detailed information.

This issue may not be addressed immediately. But we've added this to our backlog and will review it when planning future updates. Feel free to contact us if you have other problems.

Lucy

x3style
Hello, thank you for taking the time to share such detailed information.

This issue may not be addressed immediately. But we've added this to our backlog and will review it when planning future updates. Feel free to contact us if you have other problems.