And VHS wasn’t intended to record the whole of the the PAL/NTSC signal either, just needed to be good enough to view the pictures. The subtitles/closed caption data could be included on several frames a second, meanwhile the several hundred or thousand other pages may only occur once every while (main and section indexes get repeated more often).
It wasn’t uncommon to see corrupt frames from broadcast tv, and I suspect FastText would take several tries to cache a page, if it didn’t see it right first time. So no surprise at all that ancient VHS tape might take a few tries to get an accurate page, and if you’ve got half an hour of footage, then why not take a look at all the versions of a page in that time to figure out a byte-perfect page. Sounds like maybe the archivists have devised some super-clever way to avoid any manual intervention, but I doubt it’s the cusp of anything.
