I did some experiments yesterday about how one might do picture-in-picture in VR180 (stereoscopic 180). The video is made for VR headsets, so I'm only providing a link to download the video instead of uploading it as a stereo 360
The monoscopic bullet time video created by the Insta360 ONE camera can easily be converted to a 3D video by showing it separately to each eye with a time offset (1 frame). Because the camera is in motion (mostly) horizontally, a time delay creates a virtual left and right eye's point of view.
I posted a video of my son the other day, and I was able to both shoot and participate in the video. I shot the video using an Insta360 ONE 360 camera on a light stand and "re-shot" the video as traditional video using Insta360's "FreeCapture" feature in the iOS app. All I did was frame the video in real time while watching it in FreeCapture mode and export it as a traditional video. It worked pretty well, but export took many minutes, which was challenging to complete on a smartphone (if it goes to sleep, the camera turns off, and it cancels the export).
TL;DR: Use ProRes, or command-line ffmpeg to get 6K into H.264 outside of standard level specs.
The problem with trying to encode and upload videos in 6K is that it's hard to encode 6K video using highly-compressed codecs that are upload friendly. H.264 is currently the standard video codec used to compress video for Internet sharing, and its highest performance level doesn't support video resolutions higher than 4K. Here are two possible solutions.
Video and stills comparison from 8 current 360 cameras including the Giroptic iO (pre-production), Insta360 Nano, LG 360 Cam, Nikon KeyMission 360, Panono, Ricoh Theta S, Samsung Gear 360 and Z CAM S1 (screengrab from 6K video).
Just before sunset today, a gorgeous double rainbow appeared over the San Francisco bay. I happened to have a fisheye lens attached to my camera, so I ran outside and snapped this shot. The rainbow stuck around for a few minutes, so I had time to shoot using a few different setups.