RB.SongInfo::pre-metadata-change

def callback(song_info, entry, user_param1, ...)

Emitted just before the changes made in the song properties window are applied to the database. This is only emitted in the single-entry case.

song_info :

instance of RB.SongInfo that is emitting the signal

entry :

the RB.RhythmDBEntry being changed

user_param1 :

first user parameter (if any) specified with the connect() method

... :

additional user parameters (if any)