mastery700 Below is just my copy/pasted response from a prior post on this issue, but it's a good place to start. Especially since you more or less already confirmed that the h264 files work and (I assume) since you specifically brought that up, it means that h265/hevc files DON'T work for you.
1.) go to the Microsoft Store and download the HEVC codec. Used to be free though now it costs $0.99, but just search reddit and a link to a free version has been posted a few times on r/oculusnsfw
2.) make sure you have the k-lite codec pack installed
The above are specifically for helping to play h265 files, which is what virtually any 5-6k+ video will be.
If you can start with the above and if it doesn't resolve your issue we can go from there!
