Informs the delegate that the capture output object emitted new metadata objects.
- iOS 6.0+
- UIKit for Mac 13.0+Beta
AVCaptureobject that captured and emitted the metadata objects.
An array of
AVMetadatainstances representing the newly emitted metadata. Because
AVMetadatais an abstract class, the objects in this array are always instances of a concrete subclass.
The capture connection through which the objects were emitted.
AVCapture object emits only metadata objects whose types are included in its
metadata property. The delegate implements this method to perform additional processing on metadata objects as they become available. If you plan to use metadata objects outside the scope of this method, you must store strong references to them and remove those references when the objects are no longer required.
This method is executed on the dispatch queue specified by the
metadata property of the capture metadata output object. Because this method may be called frequently, your implementation should be efficient to prevent capture performance problems, including dropped metadata objects.