Dolby AC-4 has inheirited the basic principles of Metadata as established in Dolby Digital and Dolby Digital Plus. Important Metadata is carried along with the essence to the decoder in the home to enhance the user experience and maintain creative intent. While some pieces of Metadata have been retained, for example Dialog Normalization (dialnorm), other Metadata has been either added or in some cases removed.


Full details of Metadata in Dolby AC-4 can be found in section 4.2.14 of ETSI TS 103 190 v1.1.1