ISO/IEC 21122-5:2022 情報技術 — JPEG XS 低遅延軽量画像符号化システム — Part 5: リファレンス ソフトウェア | ページ 2

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.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, 1. In particular, the different approval criteria needed for the different types of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, 2 (see www.iso.org/directives or www.iec.ch/members_experts/refdocs ).

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC 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 ) or the IEC list of patent declarations received (see https://patents.iec.ch ).

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of 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 www.iso.org/iso/foreword.html . In the IEC, see www.iec.ch/understanding-standards .

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.

This second edition cancels and replaces the first edition (ISO/IEC 21122-5:2020), which has been technically revised.

The main changes are as follows:

• Updated reference software.

A list of all parts in the ISO/IEC 21122 series can be found on the ISO and IEC websites.

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Introduction

This document is part of a series of standards for a low-latency lightweight image coding system, denoted JPEG XS.

It provides the software reference implementation of the ISO/IEC 21122-1 and ISO/IEC 21122-2 standards. It has been successfully compiled and tested on various operating systems at the time of writing. It is important to note that this reference software implementation represents just one way of implementing JPEG XS. This implementation can serve as a validation anchor to other implementations.

No guarantee of the quality that will be achieved by an encoder is provided by its conformance to ISO/IEC 21122-1 and ISO/IEC 21122-2, as the conformance is only defined in terms of specific constraints imposed on the syntax of the generated codestream. In particular, while sample encoder software implementations may suffice to provide some illustrative examples of which quality can be achieved within the ISO/IEC 21122 series, they provide neither an assurance of minimum guaranteed image encoding quality nor maximum achievable image encoding quality.

Similarly, the computation resource characteristics in terms of program or data memory usage, execution speed, etc. of sample software encoder or decoder implementations should not be construed as a representative of the typical, minimal or maximal computational resource characteristics to be exhibited by implementations of the ISO/IEC 21122 series.

The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) draw attention to the fact that it is claimed that compliance with this document may involve the use of a patent.

ISO and IEC take no position concerning the evidence, validity and scope of this patent right.

The holder of this patent right has assured ISO and IEC that he/she is willing to negotiate licences under reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this respect, the statement of the holder of this patent right is registered with ISO and IEC. Information may be obtained from the patent database available at www.iso.org/patents or https://patents.iec.ch .

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights other than those in the patent database. ISO and IEC shall not be held responsible for identifying any or all such patent rights.

1 Scope

This document contains the reference software of the ISO/IEC 21122 series. It acts as a guideline for implementation and as a reference for conformance testing.

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.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 21122-1 and ISO/IEC 21122-2 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

Bibliography