Go to Advanced controls located under the View menu
you will see four extra buttons above the normal play/pause button. We will use the first button from the left called the record button.
Basically we will not be cutting the video here; we will rather play the video and record the segment using the built-in VLC decoder. So seek to the position you want to start your recording and press both play and record button simultaneously
Again press the Record button when you want to stop the recording