def callback(track_transfer_batch, entry, mediatype, extension, user_param1, ...)

The batch emits this to allow the creator to provide a destination URI for an entry being transferred. This is emitted after the output media type is decided, so the usual extension for the media type can be taken into consideration.

track_transfer_batch :

instance of RB.TrackTransferBatch that is emitting the signal

entry :

the RB.RhythmDBEntry to be transferred

mediatype :

the destination media type for the transfer

extension :

usual extension for the destionation media type

user_param1 :

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

... :

additional user parameters (if any)