I'm glad you have your problem sorted out...
I'll give you one additional piece of advice. No extra charge.
You're going to need to spend some time learning how to read an interpret the MadVR diag screen. It is telling you important things.
It is telling you that your computer system, as a whole, is not fast enough to display video with MadVR at those settings at that resolution.
See the line that starts vsync? It indicates you have 16.68ms to display a frame.
Look at the 3 lines under average stats, towards the bottom. The sum of those three stats must remain less than 16.68ms, or you will have problems (dropped frames) which create visual glitches in the motion of your video playback. Your total is 26.09.
If those times continue, you will see the dropped frames count constantly increasing. That's bad.
(If you see "repeated frames" constantly increasing, that means you're playing at the wrong framerate. Also bad. With correct playback, a few seconds after playback begins, you will see both "dropped frames" and "repeated frames" stop increasing and remain constant. There are always a few, just as playback begins.)
There are exactly two ways to fix a problem like this: make your settings less demanding so that the computer needs less time to prepare the frame, or make your computer faster, so it can do more work in the 16.68ms available.
Your MadVR settings are already modest. Not much room to decrease them. You could improve performance, at the expense of quality, by changing your image upscaling algorithm from Lanczos to DXVA2 or Bilinear. If you mess with the MadVR settings, you will have to experiment, stopping and restarting playback after each change to see how the stats respond. As I said before, learning how to optimize MadVR is a whole thing in itself. You will need to spend a lot of time googling it. You can also refer to this guide:
https://wiki.mikejung.biz/index.php?title=MadVRand to this:
https://wiki.jriver.com/index.php/MadVR_Expert_Guideand to this:
https://forum.doom9.org/showthread.php?p=1709584But I think something else is at play. Based on the system configuration you have in your signature, I should think your processor and video card are adequate to run MadVR at these settings. The problem may just be you don't have enough RAM in your system. 4GB is a paltry amount for Win7x64. 8GB is a practical minimum. You should upgrade your amount of RAM, going to 8 or 16GB, just for general system performance. With that done, you may find you can actually INCREASE your MadVR settings to improve visual quality. But as it stands, that's out of the question.
Good luck...