place cfg file in C:\Program Files (x86)\Steam\steamapps\common\call of duty 4\main

you should make a new account in cod4 called 'movie' for example and set all graphics to best. 

then play the demo on that account then type into console /exec N3Tomm 
When recording spam F11 to keep killfeed colours ( not shown crafted video ) and to keep Hud of screen.