EDIT - Ehh oops I just noticed it's about Oculus Quest... I guess that is the wireless one and my advice/experience is with the Rift. Not sure how it differs in terms of what is doing the decoding of the video so my comment below may not apply to the Quest.
It's probably not using hardware decoding, you could install and use LAV filters: https://github.com/Nevcairiel/LAVFilters/releases
(I think LAV filters alone does the trick, but just in case this might help too, free on MS store anyway: https://www.microsoft.com/store/productId/9n4wgh0z6vhq)
Also I'd recommend using DeoVR (or SLRs own player) over the SkyboxVR player. Does not have the fancy room but far better video support and adjustment options.