Music Libraries are plug-ins that provide the data for the tracks in the Playlist so it's easy to organize and cache your music collection. The library plug-in that installs with QCD performs CDDB lookups for CDs and MP3 , reads ID3 tags for MP3 files, allows you to edit the information, and so on. You can also import and export libraries.
Developers can create library plug-ins that can also collect and organize all CDs and tracks that, in turn, get used by QCD (the installed library plug-in doesn't do this).
To select a library plug-in to launch
In the top left corner of the base skin, click the green Main Menu button, choose Preferences > Plug-ins > Libraries/Caches, and then choose the format you want.