MPEG provides different kinds of support to implementers. Firstly, a Technical Report is issued that contains software that describes the decoder and an example encoder. This software can be used by implementers to analyze and to get accustomed with the algorithms, and could be used as a basis for an implementation. This encoder can be used to generate test sequences. The Technical Report is published as part 5 of the standard, i.e. ISO/IEC 11172-5 for MPEG-1 and ISO/IEC 13818-5 for MPEG-2, ISO/IEC 13818-5 for MPEG-2 AAC.
Secondly, a conformance document is issued. This document provides guidelines to test conformance to the standard of bitstreams, and conformance of decoders. It also describes the accuracy level that a decoder should meet in order to be called an MPEG audio decoder or a 'high accuracy' MPEG Audio decoder.
An important part of the conformance document is a set of bitstreams and the corresponding reference decoder output, that address several functionalities of the decoder. The conformance document is published as part 4 of the standard, i.e. ISO/IEC 11172-4 for MPEG-1 and ISO/IEC 13818-4 for MPEG-2 and ISO/IEC 13818-4 for MPEG-2 AAC.
For MPEG-2 ISO/IEC 13818-5 there are reference bitstreams needed to perform the conformance test of the decoder implementations. These can be downloaded from the ITTF website.