- 
Tracks — Data structure to store metadata about an iPod track
- 
Playlists — Data structure to represent an iPod playlist
- 
Smart Playlists — Data structure to represent an iPod smart playlist
- 
Artwork — Data structure to store iPod artwork (album covers)
- 
Chapter Data — Data structure to store chapter data for tracks
- 
Device — Data structure holding information about the iPod (model, mount point, etc.)