ISO/IEC 18477-4:2017

INTERNATIONAL ISO/IEC
STANDARD 18477-4
First edition
2017-10
Information technology — Scalable
compression and coding of
continuous-tone still images —
Part 4:
Conformance testing
Technologies de l'information — Compression échelonnable et codage
d'images plates en ton continu —
Partie 4: Essai de conformité
Reference number
©
ISO/IEC 2017
© ISO/IEC 2017, Published in Switzerland
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ii © ISO/IEC 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms, definitions, abbreviated terms and symbols . 2
3.1 Terms and definitions . 2
3.2 Symbols . 8
3.3 Abbreviated terms . 8
4 Conventions . 8
4.1 Conformance language . 8
4.2 Operators . 9
4.2.1 Arithmetic operators . 9
4.2.2 Logical operators . 9
4.2.3 Relational operators . 9
4.2.4 Precedence order of operators . 9
4.2.5 Mathematical functions .10
5 Conventions .10
6 General description .10
6.1 Overview .10
6.2 Parts and profiles .10
6.3 Decoders .11
6.4 Implementation conformance statement .11
6.5 Abstract test suites .11
6.6 Decoder conformance testing procedures .11
7 Copyright .11
8 Conformance files availability and updates .11
Annex A (normative) Decoder conformance testing procedures .12
Annex B (normative) Decoder conformance tests .18
Annex C (normative) Codestream conformance .29
Bibliography .31
© ISO/IEC 2017 – All rights reserved iii

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
A list of all parts in the ISO/IEC 18477 series can be found on the ISO website.
iv © ISO/IEC 2017 – All rights reserved

Introduction
The ISO/IEC 18477 series, also known under the term JPEG XT, specifies lossy and lossless codestream
formats for storage of continous-tone high and low dynamic range photographic content. All parts
of the ISO/IEC 18477 series are compatible to the Recommendation ITU-T T.81 | ISO/IEC 10918, also
commonly known as JPEG. That is, any decoder conforming to the latter standard will be able to
reconstruct codestreams from the ISO/IEC 18477 series to an 8 bits/sample image. Additional features
offered by ISO/IEC 18477, such as representation of intermediate or high-dynamic range images,
or lossless reconstruction require an extended decoder that implements, in addition to the Rec.
ITU-T T.81 | ISO/IEC 10918-1, also one or multiple members of ISO/IEC 18477.
This document provides the framework, concepts and methodology for testing codestreams and
implementations, and the criteria to be achieved to claim conformance to the parts and profiles
of ISO/IEC 18477. The objective of this document is to promote interoperability between JPEG XT
decoders, and to test these systems for conformance to one or multiple specifications that are part
of the JPEG XT. Conformance testing is the testing of a candidate implementation for the existence of
specific characteristics required by a standard. It involves testing the capabilities of an implementation
against the conformance requirements in the relevant standard.
The purpose of this document is to define a common test methodology, to provide a framework for
specific abstract test suites (ATS) and to define the procedures to be followed during conformance
testing.
Any organization contemplating the use of the test methods defined in this document should carefully
consider the constraints on their applicability. Conformance testing does not include robustness testing,
acceptance testing, and performance testing, all of which are outside the scope of this text.
© ISO/IEC 2017 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 18477-4:2017(E)
Information technology — Scalable compression and
coding of continuous-tone still images —
Part 4:
Conformance testing
1 Scope
This document specifies the framework, concepts, methodology for testing, and criteria to be achieved
to claim conformance to one or multiple parts of ISO/IEC 18477 as listed below. It provides a framework
for specifying abstract test suites and for defining the procedures to be followed during conformance
testing.
This document
— specifies conformance testing procedures for decoding of ISO/IEC 18477-1, 18477-2, ISO/IEC 18477-
6, ISO/IEC 18477-7, ISO/IEC 18477-8 and ISO/IEC 18477-9,
— specifies conformance testing procedures for codestreams to the above International Standards,
— specifies codestreams, decoded images, and error metrics to be used within the decoder testing
procedures, and
— specifies abstract test suites.
This document does not include the following tests:
— testing decoders for conformance to ISO/IEC 18477-3 only. ISO/IEC 18477-6, ISO/IEC 18477-
7, ISO/IEC 18477-8 and ISO/IEC 18477-9 are extensions of ISO/IEC 18477-3 and the required
functionality of ISO/IEC 18477-3 is tested as part of the former standards. Testing codestreams for
conformance to ISO/IEC 18477-3 is specified in C.2;
— testing codestreams for conformance to ISO/IEC 18477-7 beyond testing them for conformance
to individual profiles of this document. Testing such codestreams ("full profile codestreams") for
syntactical correctness is, however, covered by testing them for conformance to ISO/IEC 18477-3;
— testing of the composition of background and foreground for images reconstructed from
ISO/IEC 18477-9 codestreams as this operation is application dependent;
— acceptance testing: the process of determining whether an implementation satisfies acceptance
criteria and enables the user to determine whether or not to accept the implementation. This
includes the planning and execution of several kinds of tests (e.g. functionality, quality, and speed
performance testing) that demonstrate that the implementation satisfies the user requirements;
— performance testing: measures the performance characteristics of an implementation under test
(IUT) such as its throughput, responsiveness, etc. under various conditions.
— robustness testing: the process of determining how well an implementation process data which
contains errors.
The ISO/IEC 18477 series consists of multiple parts, each of which defines one or multiple profiles.
A given IUT (implementation under test) may claim to implement various parts and profiles of
ISO/IEC 18477 at once. To test such implementations, they have to be tested with the Abstract Test
Suites of each part and profile they claim to conform to.
© ISO/IEC 2017 – All rights reserved 1

2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 18477-1, Information technology — Scalable compression and coding of continuous-tone still
image
...