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

Media Data Atom TypesSprite Media Atom and Data TypeskSpritePropertyBackgroundColorA leaf atom containing the background color property which is of type RGBColor. This atom is used ina sprite track’s MediaPropertyAtom atom container.kSpritePropertyOffscreenBitDepthA leaf atom containing the preferred offscreen bit depth which is of type short. This atom is used in asprite track’s MediaPropertyAtom atom container.kSpritePropertySampleFormatA leaf atom containing the sample format property, which is of type short. This atom is used in a spritetrack’s MediaPropertyAtom atom container.kSpriteImageRegistrationAtomTypeSprite images have a default registration point of 0, 0. To specify a different point, add an atom of typekSpriteImageRegistrationAtomType as a child atom of the kSpriteImageAtomType and set itsleaf data to a FixedPoint value with the desired registration point.kSpriteImageGroupIDAtomTypeYou must assign group IDs to sets of equivalent images in your key frame sample. For example, if thesample contains ten images where the first two images are equivalent, and the last eight images areequivalent, then you could assign a group ID of 1000 to the first two images, and a group ID of 1001 tothe last eight images. This divides the images in the sample into two sets. The actual ID does not matter,it just needs to be a unique positive integer.Each image in a sprite media key frame sample is assigned to a group. Add an atom of typekSpriteImageGroupIDAtomType as a child of the kSpriteImageAtomType atom and set its leaf datato a long containing the group ID.Important You must assign group IDs to your sprite sample if you want a sprite to display images withnon-equivalent image descriptions (i.e., images with different dimensions).For each of the following atom types (added to QuickTime 4)—except kSpriteBehaviorsAtomType—youfill in the structure QTSpriteButtonBehaviorStruct, which contains a value for each of the four states.kSpriteBehaviorsAtomTypeThis is the parent atom of kSpriteImageBehaviorAtomType, kSpriteCursorBehaviorAtomType,and kSpriteStatusStringsBehaviorAtomType.kSpriteImageBehaviorAtomTypeSpecifies the imageIndex.kSpriteCursorBehaviorAtomTypeSpecifies the cursorID.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.217