As you have probably noticed, 3D 360 cameras are one of the major trends of 2017 with multiple 3D 360 cameras released for consumers (e.g., Vuze, TwoEyesVR, and Hubblo VR) and for professionals (e.g., Insta360 Pro). One of the 360 video sharing platforms that supports 4k 3D 360 videos is VeeR.tv.
VeeR.tv is a platform for user-generated 360 videos, and supports uploads in 2D 360, 3D 360 over-under format, and 3D 360 side-by-side format. I’ve been able to upload up to 4k. (I haven’t tested higher resolutions.)
VeeR.tv is currently available for Android, iOS, Samsung Gear VR (reviewed here) and via most modern web browsers. It will soon be available for HTC Vive (reviewed here), Oculus Rift (reviewed here), Playstation VR (reviewed here), and Mi VR.
Uploaded videos can be shared on any of the supported platforms or via URL, and can also be embedded on a website.