1)Files should not be hacked during play,pause etc
2)They should be either hided or not shown during play,pause etc
3)All files should be in encrypted state if shown at any point of time,encryotion and decryption is already there in app so nothing to worry at this point.
4)It should not be detected by third party tools or any other tools .
This is very small task which can be done in an [url removed, login to view] do not apply if you do not have similar experience .Have more tasks which will be given to right selected [url removed, login to view] work on Teamviewer.