Quicktime File Format (2012-08-14).pdf

Media Data Atom TypesFlash MediakActionListAtomType 1, 1[(ActionListAtoms)] // may contain nested conditionalactionsFlash MediaNote Flash media is deprecated in the QuickTime file format. The information that follows is intendedto document existing content containing flash media and should not be used for new development.Flash is a vector-based graphics and animation technology designed for the Internet. As an authoring tool,Flash lets content authors and developers create a wide range of interactive vector animations. The filesexported by this tool are called SWF (pronounced “swiff”) files. SWF files are commonly played back usingMacromedia’s ShockWave plug-in. In an effort to establish Flash as an industrywide standard, Macromedia haspublished the SWF File Format and made the specification publicly available on its website athttp://www.macromedia.com/software/flash/open/spec/.The Flash media handler, introduced in QuickTime 4, allows a Macromedia Flash SWF 3.0 file to be treated asa track within a QuickTime movie. Thus, QuickTime 4 extends the SWF file format, enabling the execution ofany of its wired actions. See “Adding Wired Actions To a Flash Track” (page 347) for an example of how to addwired actions.Because a QuickTime movie may contain any number of tracks, multiple SWF tracks may be added to the samemovie. The Flash media handler also provides support for an optimized case using the alpha channel graphicsmode, which allows a Flash track to be composited cleanly over other tracks.QuickTime supports all Flash actions except for the Flash load movie action. For example, when a Flash trackin a QuickTime movie contains an action that goes to a particular Flash frame, QuickTime converts this to awired action that goes to the QuickTime movie time in the corresponding Flash frame.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.234