Hi, I need some help. I'm trying to create a blu ray disc from 4K video shot on my iphone 6s plus and iphone 7 plus. I am using roxio toast 15. For the video quailty settings, I choose "best". I have attached a screenshot of the settings. My question is, Why does roxio reencode my video? It takes hours for reencoding, Why does it do that? Why can't it just use the original video quality? Thanks!