D3D11+switching display mode=skipped beginning

Hi,

I am currently setting up my new media PC (Intel NUC Hades Canyon) and specific settings brings me to trouble.
Since it's a new PC, I would like to use hardware acceleration D3D11. Choosing that option and also activating display mode switch, makes the videodecoding freeze for about 7 seconds. Well, it skips the beginning and display the image in future.
Because it is hard to describe, I made a video, to show:

https://youtu.be/6vtgKSi32zc

The sound is muted, because of YouTube, but when I start the video, the sound plays fine directly at beginning and the video plays normally, when the sound pass the position of the frozen image, so it seems related only to videodecoding.

So what do I show:

1. D3D11+Automatic+changing refresh rate = freeze for about 7 seconds
   
2. D3D11+Automatic+no change of refresh rate = no issue
   
3. Software decoder+automatic freshare change = no issue
   
4. DXVA2(native)+automatic refresh rate = no issue
   
5. D3D11+force Intel HD 630+automatic refresh rate = it seems to be ignored and software decoder is used
   

It seems unrelated to the Codec, I tried h.264 8-Bit and HEVC 10-Bit. Both files shows the same symptom.
I would like to see Hardware Decoding made by Intel HD 630 (better support) and image quality improvement by Radeon RX Vega M Graphics. (Is this possible anyway?) "Automatic (Native)" picks the Radeon for Decoding I think. Forcing Intel HD 630 by Windows makes also madVR goes over Intel HD.
Is there any downside to choose "the old" DXVA2 instead D3D11?

So..... do you have any idea whats the cause is? The drivers are the current one offered by Intel. What can I try? Is it related to LAV Decoder? Is it an issue of the graphics driver? It looks like D3D11 is not ready after a refresh rate change.

I appreciate any tip and idea you have. Thank you

The benefit of D3D11 compared to DXVA2 copyback is that it may give a bit better performance. Most noticeable on 4k resolution. If you mostly only play 1080p stuff, then using DXVA2 is usually perfectly fine too.
The downside of D3D11 decoding is that it currently does not yet support deinterlacing in Madvr (when running in native mode). Not a big problem since normal video is not interlaced.
If DXVA2 works for you, then there is no reason to not use it. D3D11 will probably get improvements in future Madvr versions.

Display mode switching itself can take a few seconds.

Regarding the long delay, there are several things that may cause this. For example something else running at same time that also uses D3D11, such as a game, a browser, or animated desktop background. Disabling DWM.exe (to force Aero Basic Theme in Windows) can also cause it.

In LAV Video decoder you can select which GPU must be used, if both are exposed, which is not always the case for switchable laptop graphics. But generally speaking I would not advice to use different GPUs for decoding and rendering. Copying the data back and forth hurts performance.

Also disable fullscreen exclusive mode in Madvr settings. That can also cause a delay on Windows 10.

Thank you for explain. So I go for DXVA2 and let Windows decide himself which GPU to use.

4K will play a role in soon future for me. This PC should be ready for.

The contect I play is always progressive. Interlaced material will be deinterlaced by myelf with QTGMC or whatever the source wants. So no issue for me.

To your speculation:
None of this is the case. No game is running, no other application in background, no browser with hardware acceleration. Only MPC-HC which makes use of GPU regarding in task-manager.

Also: It's always repeatable in the exact same way, without excuse and starts at the exact same frame in ahead, which shouldn't be displayed at the moment. You can see at the beginning of my uploaded video. So no performance issue at all.
It's like: "Oh, I am not ready after a change of refresh rate. I will already display the frame ahead until I am ready and wait for the sound to be sync again."
But then again I ask myself: How does the program know, at which frame it can go fine? Why DXVA2 works without issue directly after a refresh rate change?

DWM is not disabled. Is it even possible? I thought Microsoft removed the option for Winodws 10.

Exclusive mode is also not enabled. It's "windowed fullscreen". I just set the hook to start MPC-HC in fullscreen. But it also happens when I start the file in windowmode.

Would it be smart to post this in the madVR thread?

EDIT: Okay, after some more tries with DXVA2, software decoding is still the best ^^ But D3D11 would be a nice, very useful alternative, if it would work properly.

Yes, posting in Madvr thread is good idea.

D3D11 is still a bit experimental. It would not surprise me if this gets fixed in next Madvr update. Unfortunately, Madshi is currently busy with commercial work, so the wait takes longer than normal.