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

Media Data Atom TypesObject TracksThe number of entries in the track reference array atom is determined by dividing the size of the atom bysizeof (QTVRTrackRefEntry).kQTVRPreviewTrackRes is a special value for the trackResolution field in the QTVRTrackRefEntrystructure. This is used to indicate the presence of a special preview image track.Object TracksNote VR Media is deprecated in the QuickTime file format. The information that follows is intendedto document existing content containing VR Media and should not be used for new development.A movie’s object track is a track that contains information about the object nodes in a scene. The media typeof the object track is 'obje'. Each sample in an object track corresponds to a single object node in the scene.The samples of the object track contain information describing the object images stored in the object imagetrack.These object information samples parallel the corresponding node samples in the QTVR track and are equalin time and duration to a particular object node’s image samples in the object’s image track as well as theobject node’s hot spot samples in the object’s hot spot track.Object tracks do not have a sample description (although QuickTime requires that you specify a dummy sampledescription when you call AddMediaSample to add a sample to an object track). The sample itself is an atomcontainer that contains a single object sample atom and other optional atoms.Object Sample Atom Structureobject sample atom describes a single object, including information about the default viewing angles and theview settings. The structure of an object sample atom is defined by the QTVRObjectSampleAtom data type:typedef struct VRObjectSampleAtom {UInt16UInt16UInt16UInt16UInt16UInt16UInt32majorVersion;minorVersion;movieType;viewStateCount;defaultViewState;mouseDownViewState;viewDuration;2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.302