Mostly wanted to fully automate the pipeline (auto-rewind tape, scan tape head position, etc) and iMovie is just using the same AVFoundation APIs under the scene that you can call manually. Took some notes here if helpful:
https://pierce.dev/notes/automating-our-home-video-importsWish vhsdecode was easier to use in practice! Such a cool idea but a bit too inconvenient to hack your own hardware like this...