Video What influences the quality of videos inserted into Unity scenes?

I have inserted videos into my unity scene and they work (with attached video player to object). When I build my game however (.exe file), the videos are not super fluent (they run better in unity itself). What are the screws I have to work on here?

Is it because my computer is generally not the best? So does it depend on computer power, or is it something in the program settings that I can adjust to solve this issue?

Thank you for your help!