Just found this series of links, explaining hard way of capturing videotapes - directly from VCR heads!

https://github.com/oyvindln/vhs-decode

thread with more links and history (VERY tech heavy!) 

https://forum.videohelp.com/threads/394168-Current-status-of-ld-decode-vhs-decode-%28true-backup-of-RF-signals%29

some notes on cx-series of capture cards might be applicable even for using them normally