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  "title" : "Metadata Format Description Constants"
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# Metadata Format Description Constants

Constants that identify metadata format descriptions.

## Topics

### Constants

[`let kCMMetadataBaseDataType_AffineTransformF64: CFString`](/documentation/CoreMedia/kCMMetadataBaseDataType_AffineTransformF64)

A type that identifies a 3x3 matrix of 64-bit big endian floating point numbers in a row-major order that specify an affine transform.

[`let kCMMetadataFormatDescriptionKey_ConformingDataTypes: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_ConformingDataTypes)

A key that identifies the conforming data types.

[`let kCMMetadataFormatDescriptionKey_DataType: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_DataType)

A key that identifies the data type.

[`let kCMMetadataFormatDescriptionKey_DataTypeNamespace: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_DataTypeNamespace)

A key that identifies the data type namespace.

[`let kCMMetadataFormatDescriptionKey_LanguageTag: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_LanguageTag)

A key that identifies the language tag.

[`let kCMMetadataFormatDescriptionKey_LocalID: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_LocalID)

A key that identifies the local identifier.

[`let kCMMetadataFormatDescriptionKey_Namespace: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_Namespace)

A key that identifies the namespace.

[`let kCMMetadataFormatDescriptionKey_SetupData: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_SetupData)

A key that identifies setup data.

[`let kCMMetadataFormatDescriptionKey_StructuralDependency: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_StructuralDependency)

A key that identifies the structural dependency.

[`let kCMMetadataFormatDescriptionKey_Value: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionKey_Value)

A key that identifies the value.

[`let kCMMetadataFormatDescriptionMetadataSpecificationKey_DataType: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionMetadataSpecificationKey_DataType)

A specification key that identifies the data type.

[`let kCMMetadataFormatDescriptionMetadataSpecificationKey_ExtendedLanguageTag: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionMetadataSpecificationKey_ExtendedLanguageTag)

A specification key that identifies the extended language tag.

[`let kCMMetadataFormatDescriptionMetadataSpecificationKey_Identifier: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionMetadataSpecificationKey_Identifier)

A specification key that identifies the identifier.

[`let kCMMetadataFormatDescriptionMetadataSpecificationKey_SetupData: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionMetadataSpecificationKey_SetupData)

A specification key that identifies the setup data.

[`let kCMMetadataFormatDescriptionMetadataSpecificationKey_StructuralDependency: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescriptionMetadataSpecificationKey_StructuralDependency)

A specification key that identifies dependencies.

[`let kCMMetadataFormatDescription_StructuralDependencyKey_DependencyIsInvalidFlag: CFString`](/documentation/CoreMedia/kCMMetadataFormatDescription_StructuralDependencyKey_DependencyIsInvalidFlag)

A specification key that identifies the depencency isn’t valid.


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