Programming With QuickTime VR
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A QuickTime atom container is a basic structure for storing information in QuickTime files. An atom container is a tree structured hierarchy of QT atoms. By definition, only the leaf atoms in the hierarchy contain data. Intermediate atoms serve as parent atoms that contain any number of child atoms, which may in turn be either leaf atoms or more parent atoms. Each parent's child atom is uniquely identified by its atom type and atom ID. The atom container itself is considered the parent of the highest level atoms.
Many of the atom types contained in the VR world and node information atom containers are unique within their container. For example, each has a single header atom. Most of the parent atoms within an atom container are unique as well, such as the node parent atom in the VR world atom container or the hot spot parent atom in the node information atom container. For these one time only atoms, the atom ID is always set to 1. Unless otherwise mentioned in the descriptions of the atoms that follow, assume that the atom ID is 1.
Many of the atom structures contain two version fields, majorVersion and minorVersion . The values of these fields correspond to the constants kQTVRMajorVersion and kQTVRMinorVersion found in the header file QuickTimeVRFormat.h . For QuickTime 2.0 files, these values are 2 and 0.
QuickTime provides many routines for creating and accessing atom containers. Those are described in QuickTime 3 Reference .
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