I went to Barcelona center today to try out some of the Galaxy S7 shooting modes. Here’s a sample video taken with the Samsung Galaxy S7 edge showing the slow motion video recording mode. In the S7 shooting modes info it says that you can play a specific section of each video in slow motion after recording it.
So basically, it records a video in high-frame rate and you can clearly see it when viewing it on the screen. Than after the video is captured, it allows you to view a specific areas in slow-motion in playback.