Agreed, one to one is the only way to learn anything, but you can still use video to back it up. I train with Sensei Julian Mead in RyuKyu Kobujutsu, but being the busy man he is, it's not on a regular weekly basis. When I do get the opportunity, at courses etc, I make sure I video tape important parts of the content such as kihons, combinations and kata. That way I can refer back to my instructors demonstration for help and then when I train with him I can ask him to review what I have learnt and offer feedback for improvement.