The title that iTunes uses when it sorts by album title.
If no sort title is specified, this property is
nil and iTunes uses the value of the
title property when it sorts by album title.
Obtaining Album Information
The rating of this album.
Indicates whether the rating of this album was computed based upon the ratings of individual tracks in the album.
Whether this album is gapless.
The index (1, 2, 3, and so on) of the disc within an album that is a multiple-disc set.
The number of discs in this multiple-disc set.
The name of the artist associated with this album.