CHAPTER 9
784
Multimedia Features
least the following formats (assuming the platform has sufficient hardware and
OS support to play sounds at all):
R
C
B
E
8000, 11,025, or 22,050 samples per second
1 or 2 channels
8 or 16 bits per channel
Raw
,
Signed
, or
muLaw
encoding
If the encoding (
E
) is
Raw
or
Signed
,
R
must be 11,025 or 22,050 samples per
channel. If the encoding is
muLaw
,
R
must be 8000 samples per channel,
C
must
be 1 channel, and
B
must be 8 bits per channel. Sound players should be prepared
to convert between formats, downsample rates, and combine channels as neces-
sary to render sound on the target platform.
9.3 Movies
Note:
The features described in this section are obsolescent and their use is no longer
recommended. They are superseded by the general multimedia framework described
in Section 9.1, “Multimedia.”
PDF includes the ability to embed
movies
within a document by means of movie
annotations (see “Movie Annotations” on page 639). Despite the name, a movie
may consist entirely of sound with no visible images to be displayed on the
screen. The
Movie
and
A
(activation) entries in the movie annotation dictionary
refer, respectively, to a
movie dictionary
teristics of the movie and a
movie activation dictionary
how it should be presented.
TABLE 9.30 Entries in a movie dictionary
KEY
TYPE
VALUE
F
file specification
(Required)
A file specification identifying a self-describing movie file.
Note:
The format of a self-describing movie file is left unspecified, and there is
no guarantee of portability.
Aspect
array
(Optional)
The width and height of the movie’s bounding box, in pixels, spec-
ified as
[
width height
].
This entry should be omitted for a movie consisting
entirely of sound with no visible images. See implementation note 151 in Ap-