It may be more efficient and convenient for application to use this signal instead of metaDataChanged(). metaDataChanged() signal is emitted for compatibility, backends should emit both signals. Signal added QMetadataReader/WritterControl, QMediaObject and QMediaRecorder. Change-Id: I5ca34a40e64b22034e6fde8cd7f9735cc3f72c68 Reviewed-by: Michael Goddard <michael.goddard@nokia.com>