The following article provides information on how to move videos from a YouTube account into a Panopto account along with subtitles (captions) that may have been manually created.
Tutorial Video
How to download videos and subtitles from the eCampusvideo YouTube account and upload them to the eCampusvideo Panopto account.
Subtitle File Conversions
YouTube creates SBV or TXT files. Panopto does not accept these.
https://www.public.asu.edu/~saghafoo/sbv-to-srt/ - Free online tool to convert files for Panopto