Wired Movies and Sprites

Extending the SWF Format

QuickTime 4 extends the SWF file format to allow the execution of any of its wired actions, in addition to the much smaller set of Flash actions. For example, you may use a SWF file as a user interface element in a QuickTime movie, controlling properties of the movie and other tracks. QuickTime also allows SWF files to be compressed using the zlib data compressor. This can significantly lower the bandwidth required when downloading a SWF file when it is in a QuickTime movie.

By using wired actions within a Flash track, compressing your Flash tracks, and combining Flash tracks with other types of QuickTime media, you can create compact and sophisticated multimedia content.

The SWF File Format Specification consists of a header followed by a series of tagged data blocks. The types of tagged data blocks you need to use are the DefineButton2 and DoAction . The DefineButton2 block allows Flash actions to be associated with a mouse state transition. The DoAction allows actions to be executed when the tag is encountered. These are analogous to mouse-related QT Event handlers and the Frame Loaded event in wired movies.

Flash actions are stored in an ActionRecord . Each Flash action has its own tag, such as ActionPlay and ActionNextFrame . QuickTime defines one new tag: QuickTimeActions , which is 0xAA . The data for the QuickTimeActions tag is simply a QTAtomContainer with the QuickTime wired actions to execute in it.

There are also fields you need to change in order to add wired actions to a SWF file. Additionally, there is one tag missing from the SWF file format that is described below.

What You Need to Modify