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CHAPTER 9                                                         Multimedia Features



• Media objects may have multiple renditions, which can be chosen at play-time
  based on considerations such as available bandwidth.
• Document authors can control play-time requirements, such as which player
  software should be used to play a given media object.
• Media objects can be played in various ways; for example, in a floating window
  as well as in a region on a page.
• Future extensions to the media constructs can be handled in an appropriate
  manner by current viewer applications. Authors can control how old viewers
  treat future extensions.
• Document authors can adapt the use of multimedia to accessibility require-
  ments.
• On-line media objects can be played efficiently, even when very large.
The following list summarizes the multimedia features and indicates where each
feature is discussed:

• Section 9.1.1, “Viability,” describes the rules for determining when media ob-
  jects are suitable for playing on a particular system.
• Rendition actions (see “Rendition Actions” on page 668) are used to begin the
  playing of multimedia content.
• A rendition action associates a screen annotation (see “Screen Annotations” on
  page 639) with a rendition (see Section 9.1.2, “Renditions”).
• Renditions are of two varieties: media renditions (see “Media Renditions” on
  page 762) that define the characteristics of the media to be played, and selector
  renditions (see “Selector Renditions” on page 763) that enables choosing which
  of a set of media renditions should be played.
• Media renditions contain entries that specify what should be played (see Sec-
  tion 9.1.3, “Media Clip Objects”), how it should be played (see Section 9.1.4,
  “Media Play Parameters”), and where it should be played (see Section 9.1.5,
  “Media Screen Parameters”).
• Section 9.1.6, “Other Multimedia Objects,” describes several PDF objects that
  are referenced by the major objects listed above.

Note: Some of the features described in the following sections have references to cor-
responding elements in the Synchronized Multimedia Integration Language (SMIL
2.0) standard (see the Bibliography).

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