Wired Movies and Sprites

Sprite Tracks

For sprites in a sprite track, all sprite images are stored in one of the sprite track's key frame samples. This allows the sprites in the sprite track to share images. A sprite's image index (kSpritePropertyImageIndex ) specifies the sprite's current image in the pool of available images. All images assigned to a sprite must share the same image description, unless you assign group IDs (kSpriteImagePropertyGroupID ).

For sprites in a sprite track, you modify a sprite property by creating an override sample of the appropriate type.

Three sprite track properties, kSpriteTrackPropertyBackgroundColor , kSpriteTrackPropertyOffscreenBitDepth , and kSpriteTrackPropertySampleFormat , describe properties of a sprite track in a QuickTime movie. These properties are discussed in more detail in Chapter 2, "The Sprite Media Handler."