If you've specified the duration for each slide in the PowerPoint presentation or configured the animation effects to be played automatically, then this time will be taken into account in the final video. If your presentation consists of slides of different lengths, then adjust the duration of the slide show for each slide by specifying the time for changing slides in PowerPoint.
If your presentation contains animations, transitions, we recommend that you use the following settings for each slide:
Change the start option for each animation effect on the Animations tab in PowerPoint: choose Start With Previous or Start After Previous
Set the Duration and Delay options of each effect (if necessary)
Select the On Mouse Click check box on the Transitions tab to advance the slide when you click the mouse.