VLC can loop a part of a song or a video over and over again. To use this feature, go to Tools > Advanced controls. The loop button should appear on the playback bar. Open the file you want to start the loop at. Click on the b~'ttcin again at the part of the file you want the loop to end. VLC will now start playing that portion of a file in an endless loop till you click on the loop button again to stop the loop.