Get latest video file captured by device

Hi All

I have an app that runs in the background for a media event that is coming up, the requirement is for the app to detect when the phone captures a new video using the camera (with the native functionality of the phone, the standard camera app) and when a new file is detected it uploads that file to a server for displaying on their tv’s they will have at the event.

So essentially all I am struggling with is having the app get the latest video file that is in the gallery. From there I will do all the checks etc.

So anyone have suggestions on how to get the latest video file captured on a device?