ÖNORM EN ISO/IEC 11172-4

This part of ISO/IEC 11172 specifies how tests can be designed to verify whether bitstreams and decoders meet requirements specified in parts 1, 2 and 3 of ISO/IEC 11172. In this part of ISO/IEC 11172, encoders are not addressed specifically. An encoder is entitled to be an ISO/IEC 11172 encoder if it generates bitstreams compliant with the syntactic and semantic bitstream requirements specified in parts 1, 2 and 3 of ISO/IEC 11172. Characteristics of coded bitstreams and decoders are defined for parts 1, 2 and 3 of ISO/IEC 11172. The characteristics of a bitstream define the subset of the standard that is exploited in the bitstream. Examples are the applied values or range of the picture size and bitrate parameters. Decoder characteristics define the properties and capabilities of the applied decoding process. An example of a property is the applied arithmetic accuracy. The capabilities of a decoder specify which coded bitstreams the decoder can decode and reconstruct, by defining the subset of the standard that may be exploited in decodable bitstreams. A bitstream can be decoded by a decoder if the characteristics of the coded bitstream are within the subset of the standard specified by the decoder capabilities. Procedures are descibed for testing compliance of bitstreams and decoders to the requirements defined in parts 1, 2 and 3 of ISO/IEC 11172. Given the set of characteristics claimed, the requirements that must be met are fully determined by parts 1, 2 and 3 of ISO/IEC 11172. This part of ISO/IEC 11172 summarizes the requirements, cross references them to characteristics, and defines how compliance with them can be tested. Guidelines are given how to construct tests and determine their outcome. Some actual tests are defined only for audio.