Hi!
I almost do not update this player anymore, for this reason I have reduced the cost.
For example, you can take stereo shaders for your purposes, there is such an opportunity there and already modify your player.
Also included is a file browser.
Nothing prevents you from making your own functional player for your needs. In fact, you copy the shader, attach it to your sphere, create a media player sheet, and add your 3D objects to the sphere.
As for decoding, a standard media framework is used here, you can check the operation of 8k videos in a regular Epic games player, and check the performance.
https://docs.unrealengine.com/5.2/en-US/media-framework-technical-reference-for-unreal-engine/ → please find Playback Optimization