Manually recorded videos from playback are saved to this folder
Files are numeric (e.g. 1526426401.mp4) with date stamps on when the manual record was made.
The preview videos for notifications are saved in
Camera's ID number prefixes the video name followed by a video ID number. To make it easier, use the share function then file manager within the application to see the nickname of each video and its actual recording time, then copy it to your downloads folder.