Beginning to perform in broadcast encore (6)
I believe the answer is:
replay
'encore' is the definition.
(thesaurus)
'beginning to perform in broadcast' is the wordplay.
'beginning to' suggests taking the first letters.
'in' means one lot of letters goes inside another.
'broadcast' becomes 'relay' (I've seen this before).
The initial letter of 'perform' is 'p'.
'p' put within 'relay' is 'REPLAY'.
(Other definitions for replay that I've seen before include "Match held again" , "another game" , "Repeated match" , "A cup tie; clip shown over and over" , "Repeat recording of part of game" .)