Since QuickTime 7, a new architecture has been introduced in order to read and write metainformation in a QuickTime movie. This architecture defines a new metainformation storage format called the QuickTime metadata format. In this type of storage, metadata is accessed via . There is one metadata reference per , , or . A single metadata reference can pick out one or more metadata containers, which are distinguished from one another by their .
A metadata container holds one or more metadata items. Each metadata item is accessed by a metadata item reference. A given metadata item has a number of attributes, including its and its . The key is analogous to the , insofar as it is a label for the sort of data contained in the metadata item. The of the key for a specific metadata item depends on the of that item.
The QTPlgMetaDataItem class lets you deal with such a metadata items reference
This class requires QuickTime 7 or later.
The QTPlgMetaDataItem class constructors are called when you create a new instance of the class, while the ˜QTPlgMetaDataItem class destructor, is called automatically when the class is no more in use. Also, you can invoke the class destructor by setting the instance of the class to nil.
Once a new class instance is returned, it is good practice to check the class property to be sure that the new object can be used. A QTPlgMetaDataItem object is valid if it has a valid
The class provides you with the following initializer methods: