GMC 2011 Sierra Denali Owner's Manual page 214

7-26 Infotainment System
No Folder
When the disc contains only
compressed files, the files are
located under the root folder. The
next and previous folder function
does not function on a disc that was
recorded without folders or playlists.
When displaying the name of the
folder, the radio displays ROOT.
When the disc contains only
playlists and compressed audio
files, but no folders, all files are
located under the root folder.
The folder down and the folder up
buttons search playlists first and
then go to the root folder. When the
radio displays the name of the
folder, the radio displays ROOT.
Order of Play
Compressed audio files are
accessed in the following order:
Playlists (Px).
Files stored in the root directory.
Files stored in folders in the root
directory.
Tracks are played in the following
order:
Play begins from the first track in
the first playlist and continues
sequentially through all tracks in
each playlist. When the last
track of the last playlist has
played, play continues from the
first track of the first playlist.
Play begins from the first track
in the first folder and continues
sequentially through all tracks in
each folder. When the last track
of the last folder has played,
play continues from the first
track of the first folder.
When play enters a new folder, the
display does not automatically show
the new folder name unless the
folder mode has been chosen as
the default display. The new track
name displays.
File System and Naming
The song name that displays is the
song name that is contained in the
ID3 tag. If the song name is not
present in the ID3 tag, then the
radio displays the file name without
the extension (such as .mp3) as the
track name.
Track names longer than
32 characters or 4 pages are
shortened. Parts of words on the
last page of text and the extension
of the file name do not display.