audioobject Description This empty element points to external audio data. Processing expectations There are two ways to provide content for audiodata : entityref or fileref . It is best to use only one of these methods. However, if multiple sources are provided, entityref will be used in favor of fileref . Attributes Common attributes. entityref Identifies the location of the data by external identifier (entity name) fileref Identifies the location of the data by URI format Specifies the format of the data Examples See audioobject for an example.