Hello, I have a new interesting question.

For example: A videofile wmw has 30 frames per second.

It would be a full screen video in the game.

FPS_max is limited to 60. Would it have any effect on the video?

Or would it be better to change the FPS limit to 30 before starting the video and turn it back to 60 after it ends?

The question is if the engine does need the double power to show the video if the fps is 60. Or the GPU.

It depends on whether you're rendering the level while displaying the video. If not, a higher fps_max does not matter much. If you're rendering the level and displaying the video on a level texture, it would save CPU resources to change the FPS limit to 30, but any other movement in the level is then less smooth.