How video editing softwares change the FPS from ~29.87 FPS to 30 FPS. Where do the extra frames come from?

Question

How video editing softwares change the FPS from ~29.87 FPS to 30 FPS. Where do the extra frames come from?

In: 39

Answer 1

The easiest way is that the video simply becomes shorter. The audio has to be sped up very slightly but that’s easy to do. The speed change is exactly in the ratio 1001:1000 which is too small of a change in pitch to be noticed (less than 2 cents) and means the video is only 3.6 seconds shorter per hour.