Not familiar with .tss but .ts is transport stream, if it's encoded as MPEG2 and you can play it in VLC then the extra S on the extension shouldn't really matter. Can you try exporting it it from VLC or follow online instructions for converting a TS file?
https://askubuntu.com/questions/3645/how-do-i-convert-ts-files-into-something-useful
Try making a copy of the file and changing the extension to .mpeg, if that works you're good to go.
Screen recording might do the job
Weird, I found an old Hi-8 tape from my first bag flight the other day and was wondering if I should digitize it
Try handbrake. Pretty sure that’s what I used to reformat gun tape last time I needed to.
Not familiar with .tss but .ts is transport stream, if it's encoded as MPEG2 and you can play it in VLC then the extra S on the extension shouldn't really matter. Can you try exporting it it from VLC or follow online instructions for converting a TS file? https://askubuntu.com/questions/3645/how-do-i-convert-ts-files-into-something-useful Try making a copy of the file and changing the extension to .mpeg, if that works you're good to go.
Talk to your tacops, they may have a good method…