Default [REQ] Bulk renaming application

Is there an app for bulk renaming?

For example i have a lot of mp4 files named like this


Eiffel tower.mp4
Manchester.mp4
Ukraine.mp4



And so on.



This app should remove all the extensions and rename files like this


Eiffel tower.
Manchester.
Ukraine.




OR






Eiffel tower.PDF
Manchester.PDF
Ukraine.PDF



And allow me to do vice versa as well. Is it possible?