Have you ever thought about using a screen recorder? That's what I do. I use Joyoshare's best screen recorder for PC and Mac to record and save what I want. I think it has edges over other video downloaders as it can save any part of a video or audio in any format instead of the entire one. Moreover, it supports a number of built-in video editing tools, so that you can save any online videos in the way you like. Just to add, now you can follow Joyoshare on Facebook to get an Amazon gift card or free license of this tool.