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       CHAPTER 9                                                              Multimedia Features



KEY      TYPE         VALUE

MH       dictionary   (Optional) A dictionary whose entries (see Table 9.2) must be honored for the ren-
                      dition to be considered viable.

BE       dictionary   (Optional) A dictionary whose entries (see Table 9.2) need only be honored in a
                      “best effort” sense.



                       TABLE 9.2 Entries in a rendition MH/BE dictionary
KEY      TYPE         VALUE

C        dictionary   (Optional) A media criteria dictionary (see Table 9.3).
                      Note: The media criteria dictionary behaves somewhat differently than other MH/BE
                      entries described in Section 9.1.1, “Viability.” The criteria specified by all of its entries
                      must be met regardless of whether it is in an MH or a BE dictionary. The only exception
                      is that if an entry in a BE dictionary is unrecognized by the viewer application, it does
                      not affect the viability of the object.




                         TABLE 9.3 Entries in a media criteria dictionary
KEY      TYPE         VALUE

Type     name         (Optional) The type of PDF object that this dictionary describes; if present, must be
                      MediaCriteria for a media criteria dictionary.

A        boolean      (Optional) If specified, the value of this entry must match the user’s preference for
                      whether to hear audio descriptions in order for this object to be viable. Equivalent
                      to SMIL’s systemAudioDesc attribute.

C        boolean      (Optional) If specified, the value of this entry must match the user’s preference for
                      whether to see text captions in order for this object to be viable. Equivalent to
                      SMIL’s systemCaptions attribute.

O        boolean      (Optional) If specified, the value of this entry must match the user’s preference for
                      whether to hear audio overdubs in order for this object to be viable.

S        boolean      (Optional) If specified, the value of this entry must match the user’s preference for
                      whether to see subtitles in order for this object to be viable.

R        integer      (Optional) If specified, the system’s bandwidth (in bits per second) must be greater
                      than or equal to the value of this entry in order for this object to be viable. Equiva-
                      lent to SMIL’s systemBitrate attribute.

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