Creates a format description based on the receiver's items.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
An instance of
CMMetadata sufficient to describe the contents of all the items referenced by the object.
The returned format description is suitable for use as the format hint parameter when creating an instance of
Each item referenced by the receiver must carry a non-
nil value for its
data property. An exception will be thrown if any item does not have a data type.