Microsoft's patent application describes a free-to-play system that would pause games at lulls for ads, then give players credits delaying the next ad. It suggests breaks such as loading screens or quest endings; the filing does not confirm a launch.
The system would use machine learning to select ad slots and integrate with the game engine. Other suggested moments include menus, the end of a cutscene and after a boss fight; gameplay would remain paused while an ad played.
Separately, Microsoft has experimented with a free, ad-backed tier for Xbox Cloud Gaming.
