The complete file path of a file comprises of the Base Folder, Sub Folders and File name. When this option is enabled only the file name part will be modified using the file name part of the defined rename mask. This allows files to be renamed base don new metadata without modifying structure.
The common reason for using this option is as follows. You have a folder containing songs that have not been tagged, the folder either represents an album that is not known to the Albunack Server so with the default matching options SongKong is unable to match the songs. You decide to uncheck the Only allow match if all songs in grouping match to one album option on the Basic tab to give the SongKong the best chance of finding a match. And because the existing tracks are just labelled Track1.mp3, Track2.mp3 you want to Rename files based on Metadata to give the files more useful names, but you don’t want the tracks to be moved because you know they all belong to one album. Enabling Rename file name only allows you to do this.
Regardless of the rename mask selected only the name part of the rename mask will be used to replace the name part of the existing file path. So if the existing file path has sub-folders they will remain even if the rename mask does nothave a sub folder component. If the existing file path does not have sub-folders then no sub-folders will be added even if the rename mask does have sub-folders.
e.g... assuming the song actually is With or Without You by U2 on the Joshua Tree album
Existing filepath /Music/U2/Best Of/Track1.mp3 gives Base Folder=/Music, Sub Folder=U2/The Joshua Tree and File name=Track1.mp3
Rename Mask: Artist/Album/TrackNo - Title, Rename file only:false would give
/Music/U2/The Joshua Tree/03 - With or Without You.mp3
Rename Mask: Artist/Album/TrackNo - Title, Rename file only:true would give
/Music/U2/Best Of/03 - With or Without You.mp3
Rename Mask: TrackNo - Title, Rename file only:false would give
/Music/03 - With or Without You.mp3
Rename Mask: TrackNo - Title, Rename file only:true would give
/Music/U2/Best Of/03 - With or Without You.mp3