How To Fix OBS Black Screen in Display Capture and Game Capture

There is simple steps we need to follow

1. Right click on  desktop and go to nvidia control panel or 
2. Manage 3D settings -> program setting -> Select program to customize
3. Add -> select obs studio and apply
4. Select preferred graphics processor for this progra 
5. Select integrated graphics for display capture  
6. select high performance NVIDIA processor for game capture
7.