Hey,
DVDs are absolutely fine. When I Rew/FF a blu, it 'starts off' OK, but after 2 seconds or so the image and time bar 'freeze' so you don't know where it's rewinded/ff to. But it does actually do it because when you hit play again it plays from that point.
I just can't see where it's gone to, so have no control. A bit like doing it with a blindfold on.