Can be used to uniquely identify the object represented by this element for external binding reference purposes.
The value of the refID shall be unique for each object within the AVFunction and is implementation-specific. May be a GUID.
Source
<xsi:complexType name="avClusterControlType"><xsi:annotation><xsi:documentation>Describes a full AVCluster.</xsi:documentation><xsi:documentation>The videoCluster, audioCluster, and metadataCluster elements are optional but at least one shall be present. Two or all may be present.</xsi:documentation></xsi:annotation><xsi:choice><xsi:sequence><xsi:element name="videoCluster" type="videoClusterType" minOccurs="0"/><xsi:element name="audioCluster" type="audioClusterType" minOccurs="0"/><xsi:element name="metadataCluster" type="metadataClusterType" minOccurs="0"/></xsi:sequence><xsi:element name="rawDataCluster" type="emptyElementType"/></xsi:choice><xsi:attributeGroup ref="refID"/></xsi:complexType>