Describes: what is meant by conformance of what is specified in ISO/IEC 23002-4, the structure of the reference software related to what is specified in ISO/IEC 23002-4. Currently the following profiles are included in ISO/IEC 23002-4 and in this document as reference software: ISO/IEC 14496-2 Simple Profile, ISO/IEC 14496-10 Constrained Baseline Profile, ISO/IEC 14496-10 Progressive High Profile, ISO/IEC 14496-16 SC3DMC, and ISO/IEC 23008-2 Main Profile.