General Information
Section 1
January 2009
Digital Talking-Book Player
12
Library Guide
SMIL file
where the chapter begins. The
NCX file
will also have a direct pointer to the audio clip that will render the
name of the chapter so that the user can quickly locate the navigation point of interest. Both the standard and
advanced players use information in the NCX file to report the book title and reading position location.
Before a protected book can be played, the player examines the
Authorization Object
to determine the secret key
required to extract the unique book keys from the
Authorization Object
. If the player has the key required, it will
decrypt the book keys and use them in turn to decrypt the book’s audio and navigation information. If it does not
have the secret key that this book was protected with, it will play the Façade Book.
Audio Files
db54321ann.3gp
db54321-01.3gp
db54321-02.3gp
db54321-03.3gp
db54321-04.3gp
db54321-05.3gp
db54321-06.3gp
db54321-07.3gp
SMIL Files
db54321-01.smil
db54321-02.smil
Package File
db54321.ppf
NCX File
(Navigation)
db54321.pncx
Audio File
db54321hdgs.3gp
Figure 1-6. Representation of a Typical NLS Digital Talking Book
Each navigation
mark points to a
SMIL element
within a SMIL file.
The “spine” of the
book contains a
list of SMIL files to
be played in
order.
Audio “label” clips
play when user
navigates (e.g.,
“Chapter One”).
Each SMIL
element points
to an audio clip
within an audio
file.
Authorization Object
us-nls-db54321.ao
The player contains the “private” key to
decrypt the Authorization Object which
hold the “Book Keys”
“Book Keys” required
to decrypt protected
files.
Façade Book
pdtb_protected.smil
protected.mp3
db54321.ncx
db54321.opf
