Samsung SM-N950F/DS User Manual page 120

Apps and features
Playing super slow motion videos
Select a super slow motion video and tap Play super slow-mo video.
Random background music will automatically accompany the video during playback.
To capture an image while playing a video, tap
Editing super slow motion videos
On the playback screen, you can edit the video and save it as a different file or share it.
To edit the super slow motion section, drag
Start bracket
.
to the left or right.
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Change the background
music.
End bracket
Super slow motion section