Nepomuk has been a great semantic framework in recent years with many applications like Dolphin using it for managing metadata associated with its files and resources. And now, even Amarok uses Nepomuk to fetch tracks in your computer. This collection doesn't use the SQLite backend to store statistics and metadata ( artist, album, year, genre, Labels etc ). It instead uses Nepomuk to store them and fetch them.
For more details on Nepomuk, please visit its official page.
Nepomuk is a system wide backend with multiple applications already using it for search and metadata. So when you rate a track in Amarok, it reflects in Dolphin as well. When you burn your music tracks onto a disc, the ratings will be included too! You don't have to remember where you have stored your music tracks anymore. Nepomuk fetches tracks from all over your computer. You don't have to organize your music tracks into one single folder! Imagine the number of times you downloaded a track again just 'cos you couldn't find it in your computer -- not anymore.
For your tracks to show up in Amarok, they need to be indexed by Nepomuk first. And Nepomuk does not index every file on the hard drive. Its default configuration in most Linux distributions excludes some common patterns for backup files and configuration directories and it only indexes certain directories in your home folder.
Beware: indexing files may take a lot of time depending upon the number of files that are to be indexed as well as on the amount of memory that is allowed to the desktop search for indexing. See also Search Desktop.
Directories that are to be indexed can be changed in. As of KDE 4.11, this is the dialog you will see:
The Nepomuk Collection in Amarok is a plugin that can be enabled in. After enabling, restart Amarok for the plugin to load completely.
After enabling the plugin, there will be a new collection named Nepomuk Collection containing the tracks indexed by Nepomuk.
After enabling the Desktop Search with Nepomuk, tracks and other files can be rated in the Dolphin file browser. Tracks in the Nepomuk Collection can be rated outside and rating will be shown instantly in Amarok.
Tracks shown in the Nepomuk Collection can be played even if they are moved out of their original location. They would be usable also if you rename them.
Every feature of Nepomuk can be used with created playlists too.