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

Media Data Atom TypesSprite MediaSprite MediaNote Sprite media is deprecated in the QuickTime file format. The information that follows is intendedto document existing content containing sprite media and should not be used for new development.Sprite media is used to store character-based animation data in QuickTime movies. It has a media type of'sprt'.Sprite Sample DescriptionThe sprite sample description uses the standard sample description header, as described in “Sample DescriptionAtoms” (page 99).The data format field in the sample description is always set to 'sprt'. The sprite media handler adds noadditional fields to the sample description.Sprite Sample DataAll sprite samples are stored in QT atom structures. The sprite media uses both key frames and differencedframes. The key frames contain all of the sprite’s image data, and the initial settings for each of the sprite’sproperties.A key frame always contains a shared data atom of type 'dflt'. This atom contains data to be shared betweenthe sprites, consisting mainly of image data and sample descriptions. The shared data atom contains a singlesprite image container atom, with an atom type value of 'imct' and an ID value of 1.The sprite image container atom stores one or more sprite image atoms of type 'imag'. Each sprite imageatom contains an image sample description immediately followed by the sprite’s compressed image data. Thesprite image atoms should have ID numbers starting at 1 and counting consecutively upward.The key frame also must contain definitions for each sprite in atoms of type 'sprt'. Sprite atoms should haveID numbers start at 1 and count consecutively upward. Each sprite atom contains a list of properties. Table4-13 (page 209) shows all currently defined sprite properties.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.208