If enabled the Find Duplicates within same audio format only option searches can be restricted to be within a particular format. This makes it easy to keep multiple versions of the same file but with different formats (e.g large lossless and small lossy file) whilst still finding actual duplicates within an audio format.
Remember any number of files can be considered duplicates, only one of them is kept. The rest are either deleted if When you have a duplicate songs option is set to Delete duplicates or moved to the selected folder if option is set to Move duplicate to Duplicates folder
Now of course if SongKong deletes (or moves) duplicates so there are no music files left in a folder we don’t probably want to keep the folder anymore. So if the When find duplicates delete folder and any sub folders if empty or only contains the following files is enabled if the folder is empty it is removed. Also if the folder contains any files in the list they are deleted and then if the folder is deleted if now empty.
And if its parent folder is now empty then this is deleted as well. The idea is that we don’t end up with lots of empty folders after deleting duplicate files.
We can add files to the list, and the list understands the asterisk (*) as a wildcard, so for example all jpeg files are removed because of the *.jpg rule.