Hi,
If you go to Preferences / Engine, you will see if MadMapper is running on nVidia or Intel GPU. Can you tell me which GPU it's using ?
Anyway it doesn't mean that hardware decoding will be done on nVidia GPU.
You should first update your Intel & nVidia drivers and see if the problem gets solved. Most issues on windows are solved with GPU drivers update...
Another point: using hardware decoding is great on very small CPUs (I used it to get full HD playback on Intel Nuc / Intel ComputeStick or Azus Vivostick because CPU doesn't handle a single Full HD h264 movie). But on a decent CPU, it's better to keep CPU decoding. I can decode about 8 4k movies on my desktop before getting frame drops. If you need more than your PU can give, use HAP or HapQ codec:
https://hap.video/ We have native support of this codec, it's really optimized: frames are zipped with a fast decoding library and store in a format that your graphics card can directly receive (so doing part of the decoding)
Cheers