Defines a Multimedia Content Description Interface, specifying a series of interfaces from system to application level to allow disparate systems to interchange information about multimedia content. It describes the architecture for systems, a language for extensions and specific applications, description tools in the audio and visual domains, as well as tools that are not specific to audio-visual domains. As a whole, this International Standard encompassing all of the aforementioned components is known as MPEG-7. MPEG-7 is divided into eight parts (as defined in the Foreword). This part of the MPEG-7 Standard (Part 4: Audio) specifies description tools that pertain to multimedia in the audio domain. See below for further details of application.