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IDProjectCategoryView StatusDate SubmittedLast Update
0000623madVRbugpublic2019-10-30 03:372020-03-02 17:38
Reportermeowmeow 
Assigned To 
PrioritynormalSeveritymajorReproducibilityalways
StatusnewResolutionopen 
PlatformWindowsOSWindows 10 Education 64 bitOS Version1903
Summary0000623: Presentation glitches occur when "after copy to backbuffer" set to "don't flush"
DescriptionDefine SETTING = "after copy to backbuffer" in Windowed Mode under Rendering
Define ACTIONS = "go to fullscreen or jump during a video playback"

With SETTING default to "don't flush", whenever I perform ACTIONS, presentation glitches almost always (95% of the time) occur. However if I change SETTING to "fush" or "flush & wait(sleep)" and repeat the same ACTIONS, presentation glitches NEVER occur.

I have repeated this experiment with a variety of video files, including 720p, 1080p, 2160p, HDR, SDR, and 10bit SDR, all produce the exact same result.

I also experimented with another setting "after D3D presentation" and it has no effect on presentation glitches wether it's set to "don't flush" or "flush" or "flush & wait".

Considering "don't flush" is the current default value for SETTING and that it causes the glitch problem, may I suggest that the default change to "Flush & wait" in future releases? Or will there be any negative effect from that? "Flush" also works but it uses much more CPU (about 7-8% on a 9900k, compared to 1-2% used by "Flush & wait").
Additional InformationNote: the "Decoding" is done by "D3D11" however this option is not avaiable in the drop-down menu below so I list it here. Please ignore my selection below.

My monitor is 144hz, 8bit+FRC. I selected "10bit(or higher)" under devices/properties. In NVidia control panel I have set the display profile to use 144hz, 10bit, RGB, Full.
TagsNo tags attached.
madVR Versionv0.92.17
Media Player (with version info)MPC-HC (64bit) 1.8.8 (82efc58f7) by clsid2
Splitter (with version info)LAV Splitter 0.74.1.24-git
Decoder (with version info)LAV Decoder 0.74.1.24-git
DecodingSoftware
Deinterlacingnone (progressive)
DXVA2 Scaling Activeno
Aero / Desktop CompositionOn
Problem occurs with modeall modes
GPU ManufacturerNVidia
GPU ModelEVGA 2080 Ti FTW3 Ultra
GPU Driver Version436.48
Attached Filespng file icon This_is_with_default_setting.PNG [^] (331,862 bytes) 2019-10-30 03:42

- Relationships

-  Notes
(0002574)
meowmeow (reporter)
2019-10-31 05:15

Another observation: if I set the number of frames to be presented in advance to 2, 3, or 6, then I will not need to do flushing at all (all 4 flushing options down below can be set to "don't flush") and will not get any presentation glitch. However any other number of presented frames in advance, including 1, 8, 10, etc., will give me lots of presentation glitch.
(0002577)
madshi (administrator)
2019-10-31 17:31

This is often somewhat "random". Changing the defaults might make things better for you, but could potentially introduce issues for other users.

Anyway, if these glitches only occur if you perform some kind of "action", it's not overly important, anyway. The important thing is that playback is completely smooth while you just sit there and enjoy the movie.
(0002685)
Medea (reporter)
2020-02-29 15:55

You mentioned your monitor is 144Hz. Do you happen to have a second monitor with a different refresh rate?
I've been having many presentation glitches per second (during regular playback, and even when paused) on my 144Hz monitor. Any redraw of my other, 60Hz, monitor will cause glitches.
This is a known issue with Windows and might (mostly) be fixed soon thanks to this update: https://blurbusters.com/new-windows-update-fixes-mixed-hz-multimonitor/ [^]

But for now, this made watching videos in windowed mode on my main monitor unbearable, and lately even fullscreen mode is having this issue for me. ("regular" fullscreen, not exclusive mode which I can't even get to work)
So I googled my issue, found this bug report and tried your solution.
I can confirm that changing "after copy to backbuffer" to "flush & wait (sleep)" (or any of the other flush modes) completely eliminates the glitches, and so does changing the number of frames to be presented in advance from 8 to 6 (or anything less than 8).

I don't know if I should create a separate report for my issue, but I just wanted to say thank you meowmeow for posting a working solution.
(0002686)
huhn (reporter)
2020-03-02 17:38

composition rate mismatches are a common issue with windows 10 and 7.

another workaround is overlay rendering it avoid this whole problem.
i had a report about composition rate here before.
it was out of his hands or something like that it's been years.
what so ever windows 8 fixed it too.

if you want to try getting FSE working again you can try this: with mpc-hc you can go to the properties of the exe-> compatibility and check "disable fullscreen optimisation" this restored FSE to it older glory but i have bad experience doing that in new windows versions. so do that at your own risk.

- Issue History
Date Modified Username Field Change
2019-10-30 03:37 meowmeow New Issue
2019-10-30 03:42 meowmeow File Added: This_is_with_default_setting.PNG
2019-10-31 05:15 meowmeow Note Added: 0002574
2019-10-31 17:31 madshi Note Added: 0002577
2020-02-29 15:55 Medea Note Added: 0002685
2020-03-02 17:38 huhn Note Added: 0002686


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