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                                                 765
        SECTION 9.1                                                                Multimedia



KEY   TYPE              VALUE

MH    dictionary        (Optional) A dictionary whose entries (see Table 9.11) must be honored for the me-
                        dia clip data to be considered viable.

BE    dictionary        (Optional) A dictionary whose entries (see Table 9.11) need only be honored in a
                        “best effort” sense.

        The media clip data object must be considered non-viable if the object referenced
        by the D entry does not contain a Type entry, the Type entry is unrecognized, or
        the referenced object is not a dictionary or stream. Note that this excludes the use
        of simple file specifications (see Section 3.10, “File Specifications”).

        If D references a file specification that has an embedded file stream (see Section
        3.10.3, “Embedded File Streams”), the embedded file stream’s Subtype entry is ig-
        nored if present, and the media clip data dictionary’s CT entry identifies the type
        of data.

        If D references a form XObject, the associated player is implicitly the viewer ap-
        plication, and the form XObject should be rendered as if it were any other data
        type. For example, the F and D entries in the media play parameters dictionary
        (see Table 9.14) apply to a form XObject just as they do to a QuickTime movie.

        For media other than form XObjects, the media clip object must provide enough
        information to allow a viewer application to locate an appropriate player. This can
        be done by providing one or both of the following entries:

        • A CT entry that specifies the content type of the media (the preferred method).
          If this entry is present, any player that is selected must support this content
          type.
        • A PL entry that specifies one or more players that can be used to play the refer-
          enced media. It is highly recommended if CT is present. However, see imple-
          mentation note 149 in Appendix H.

        The P entry specifies a media permissions dictionary (see Table 9.10) specifying
        the manner in which the data referenced by the media may be used by a viewer
        application. These permissions allow authors control over how their data is ex-
        posed to operations that could allow it to be copied. If the dictionary contains un-
        recognized entries or entries with unrecognized values, it should be considered
        non-viable, and the viewer application should not play the media.

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