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IDProjectCategoryView StatusDate SubmittedLast Update
0000623madVRbugpublic2019-10-30 03:372019-10-31 17:31
Assigned To 
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
Decoder (with version info)LAV Decoder
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
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.
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.

- 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

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