Hi have had the same problem, It will be great if XBMC (now Kodi) Team can implement a solution for that I have a lot of things in mind on how to do it
x) write stars in file tags, (can be turned on-off by configuration, and format can be choosed in configuration)
x) when exporting libraries writing a .nfo for each album with this knd of information
x) have a cloud server to store all libraries data as backup and be able to retrieve it...
in the mean while, this issue cn be solved with a sqlite script that can copy the rating value (last played, playcount, etc) from the old database to the new one... those are the steps to perform it:
1) download sqlitestudie, very helpfull for working with your database
2) copy the old MusicXX.db to a place where it can be found
3) scan the music lib in the new xbmc, and import .nfo files
4) locate the new MusicXX.db in your computer
5) open the sqlitestudio and creates both connections to both databases, for the old database name the connection OldDatabase
6) connect both conection and open a sql editor based on the connection of the new database
and run this query:
Code:
replace into song
(
idSong, idAlbum, idPath, strArtists, strGenres, strTitle, iTrack, iDuration, iYear, dwFileNameCRC, strFileName, strMusicBrainzTrackID, iTimesPlayed,
iStartOffset, iEndOffset, idThumb, lastplayed, rating, comment
)
select
s.idSong, s.idAlbum, s.idPath, s.strArtists, s.strGenres, s.strTitle, s.iTrack, s.iDuration, s.iYear, s.dwFileNameCRC, s.strFileName, s.strMusicBrainzTrackID, s2.iTimesPlayed,
s.iStartOffset, s.iEndOffset, s.idThumb, s2.lastplayed, s2.rating, s.comment
from song s
left join path on path.idPath = s.idPath
left join OldDatabase.path p2 on p2.strPath = path.strPath
left join OldDatabase.song s2 on p2.idPath = s2.idPath and s2.strFileName = s.strFileName
where s2.strFileName is not null