Convert the footage to Equirectangular?

have you considered using UVC FullHD Blender (free software from RICOH ) to stream the output to a PC or Mac in equirectangular and then use something like OBS to save the output as an equirectangular file? The USB cable used for streaming should charge the THETA S while you are streaming. (You may need a powered hub).

In this article, I saved a short clip with OBS to my computer from live streaming, then was able to upload it to YouTube.

This article about the RICOH R Dev Kit may be interesting. It outputs equirectangular from the camera.