How do you film a computer game and make it look clean and clear

The best way to capture a video of a computer game on your computer is to use a screencast application. A screencast application uses the output data of your computer and records it. Most applications will also record output audio, which in most cases is pretty important for computer game action. There are several different options of many platforms like this screencaster - http://camstudio.org This is a free open source project for Windows platforms.