Some action films feature a scene, often at the beginning of the movie, where the acting President of the United States is seen talking about an issue related to the plot of the film. A good example of that is at the beginning of Dawn of the Planet of the Apes at around 2:00, according to Netflix's time-stamp. In this example, Barack Obama can be seen talking about getting "your family ready for evacuation".
How do filmmakers obtain those video sequences? I can imagine that in some cases, at least, they can use real footage of past speeches but I also cannot imagine that this would be a fitting solution all the time.
So what do they do? Does the White House schedule a day where filmmakers submit texts they want the acting president to say and possibly pay for it?