Sometimes, you transfer your video files from iDevice to computer and remove them from your iDevices.
One day, you have to edit your videos in iDevices. You suddenly found there is no way to transfer the video files back to "Camera Roll". The normal sync app could only transfer video files to "Videos" and seldom app could read files from it.
This app is designed to deal with it. It can transfer your video files back to "Camera Roll" in your iDevice from computer via a USB cable.