Whats the purpose of Shuffle (albums) and Shuffle (directories) modes?
These modes can be used to reorder your playlist on album basis rather than track basis and play tracks in each album in sequential order. Shuffle (albums) is usable when your files are tagged properly (“%album artist% | %date% | %album%” evaluates to unique value for each of your album and doesn’t vary between tracks in one album); Shuffle (directories) is meant as a fallback when your tagging scheme renders Shuffle (albums) useless but you keep each album in a separate folder. Note that the album identification pattern can be customized in ‘Preferences → Advanced → Playback → Shuffle → Album grouping pattern’.