Programming With QuickTime VR
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QuickTime VR uses track references to establish a relationship between the various tracks in the file. The AddTrackReference routine is used to create the reference. A reference to a particular track is identified by its reference type and index. When you add a track reference, you supply the type and QuickTime returns an index, which always starts at 1 for a particular type. The QTVR track contains a reference to the panorama and object tracks in the movie. The reference types are kQTVRPanoramaType ( 'pano' ) and kQTVRObjectType ( 'obje' ). To add a reference to the panorama track from the QTVR track you would use the following line of code:
err = AddTrackReference (qtvrTrack, panoTrack, kQTVRPanoramaType, &index);
Because there are at most one panorama track and one object track in QuickTime VR 2.1 movies, the index is always one and hence is not stored in the file. The panorama and object tracks in turn contain track references to their image and hot spot tracks. The reference types for these are kQTVRImageTrackRefType ( 'imgt' ) and kQTVRHotSpotTrackRefType ( 'hott' ). There can be many image and hot spot tracks, so the track reference indexes returned by the AddTrackReference call are stored in data structures in the panorama and object tracks as described later in this chapter.
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