For Windows, there are some screen recording applications to help record video of screen, like DemoCreator(30 days for trial version), Camtasia(Full function for 30 days trial but high price), Adobe Captive(Great but high price). Those are able to edit your screen recording before finalizing. The free ones such as Camstudio, Jing project just can record what happened on your screen. TipCam could be better if it improve its screen recording quality.
If you want to record runescape videos, you should use some screen recorder to help you. The one I used can help me capture what's being on your computer, so you can use it to help you record video when you are playing the game.