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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 a metadata reference. 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 . 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 QTPlgMetaData class lets you manage metadata references

This class requires QuickTime 7 or later.







The QTPlgMetaData class constructors are called when you create a new instance of the class, while the ˜QTPlgMetaData 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.

The class provides you with the following initializer methods:
(source as )
This is the default constructor. The object will be initialized with the metadata reference associated to the specified source
Note: a more convenient way to access the container’s metadata is to use the object returned from the class instance in use
[Deprecated]: since version 6.1 of the plugin this redundant constructor is deprecated and will be removed from a future plugin version
(other as QTPlgMetaData)
This is the copy constructor. The properties of the object to be copied will be used to initialize the new class instance properties

indicates the four–char code that identifies the owner of this metaadata object (i.e. "moov" for movie)
a collection of objects that list all of the metadata containers associated to this metadata object


([storageFormat as ]) as integer
use this method to find about how many are associated to the metadata container specified by the optional storageFormat parameter; if you omit this parameter the result is set to the total number of contained by the metadata reference regardless of the type of metadata container
returns the number of items or 0 if some error occurs; this being the case, you can check the class property for errors
([storageFormat as ])
use this method to remove every from the metadata container specified by the optional storageFormat parameter; to remove all of the items contained by the metadata reference in use, simply omit to indicate a specific metadata container
returns nothing. Check the class property for errors
([storageFormat as ]) as
use this method to obtain a collection of associated to the metadata container specified by the optional storageFormat parameter; do not specify any storage format if you want to obtain the list of all of the owned by the metadata reference in use
returns a list of metadata items or nil if some error occurs. Check the class property for errors
(key as ) as
use this method to obtain a collection of that are labeled with the specified key. The metadata container to look for is implicitly specified by the ; if the value is , then this method will scan any metadata container associated to the metadata container in use
returns a list of metadata items or nil if some error occurs. Check the class property for errors
(item as )
use this method to set the value of an existing
returns nothing. Check the class property for errors
(item as ) as
by this method you can add a new to a metadata container; the metadata container target is implictly deduced by the of the . You can not use the constant value to specify the format of the key; this being the case, the method will fail to add the metadata item to the metadata container
returns the newly created metadata item reference or nil if some error occurs. Check the class property for errors
(key as ) as boolean
use this method to remove from the metadata container in use just the first labeled with the specified key if it exists
returns true if the metadata item has been successfully deleted or false if the deletion failed or the item does not exist. Check the class property for errors
(key as ) as boolean
use this method to remove from the metadata container in use all of the labeled with the specified key
returns true if the metadata items have been successfully deleted or false if the deletion failed. Check the class property for errors


identifies the new QuickTime metadata format
identifies the iTunes metadata format
identifies the user data format