ISO/IEC 29199-2:2020

INTERNATIONAL ISO/IEC
STANDARD 29199-2
Fourth edition
2020-05
Information technology — JPEG XR
image coding system —
Part 2:
Image coding specification
Technologies de l'information — Système de codage d'image JPEG
XR —
Partie 2: Spécification de codage d'image
Reference number
©
ISO/IEC 2020
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO/IEC 2020 – All rights reserved

Contents                                 Page
Foreword …………………………………………………………………………………………………………………………………………………v
Introduction . vi
1 Scope 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 9
5 Conventions . 9
5.6 Adaptive VLC deltaDisc tables . 25
5.7 Adaptive inverse scanning tables . 25
6 General provisions, provisions specified in annexes, and image and codestream structures . 26
6.1 General . 26
6.2 Image planes and component arrays . 26
6.3 Image windowing . 27
6.4 Image partitioning . 27
6.5 Transform coefficients and frequency bands . 28
6.6 Codestream structure . 29
6.7 Precision and word length . 29
7 Overview of decoder . 30
7.1 General . 30
7.2 Overview of parsing process . 31
7.3 Overview of the decoding process . 32
8 Syntax, semantics, and parsing process . 33
8.1 General . 33
8.2 CODED_IMAGE( ) . 34
8.3 IMAGE_HEADER( ) . 35
8.4 IMAGE_PLANE_HEADER( ) . 45
8.5 INDEX_TABLE_TILES( ) . 53
8.6 PROFILE_LEVEL_INFO( ) . 54
8.7 CODED_TILES( ) . 55
8.8 Adaptive VLC code table selection . 87
8.9 Adaptation of CBPLP state variables . 94
8.10 Adaptive CBPHP prediction . 95
8.11 Adaptive inverse scanning . 96

© ISO/IEC 2020 – All rights reserved
iii
8.12 Adaptive coefficient normalization . 99
9 Decoding process. 101
9.1 General . 101
9.2 Image decoding . 101
9.3 Image plane decoding . 102
9.4 Tile transform coefficient processing . 102
9.5 Coefficient remapping . 104
9.6 Transform coefficient prediction . 106
9.7 Derivation of quantization parameters . 115
9.8 Dequantization . 118
9.9 Sample reconstruction . 121
9.10 Output formatting. 152
Annex A (normative) Tag-based file format . 167
Annex B (normative) Profiles and levels . 195
Annex C (informative) Colour imagery representation and colour management . 199
Annex D (informative) Encoder processing . 202
Annex E (normative) Media type specification for the Annex A tag-based file format . 217
Annex F (normative) Storage in the ISO/IEC 23008-12 image file format and associated media type
registrations . 219
Bibliography . 227

© ISO/IEC 2020 – All rights reserved
iv
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
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ISO and IEC technical committees collaborate in fields of mutual interest. Other international
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work.
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 document 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 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 http://patents.iec.ch).
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
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World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT)
see www.iso.org/iso/foreword.html.
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, in collaboration
with ITU-T. The technically identical text is published as Rec. ITU-T T.832.
This fourth edition cancels and replaces the third edition (ISO/IEC 29199-2:2012), which has been
technically revised. It also incorporates the Amendment ISO/IEC 29199-2:2012/Amd.1:2017.
The main changes compared to the previous edition include:
  the specification of additional colour type identifiers;
  the specification of an alternative file storage format based on ISO/IEC 23008-12 for the storage
and interchange of JPEG XR coded images and image sequences;
  the specification of media type identifiers for use for use in various internet protocols.
A list of all parts in the ISO/IEC 29199 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

© ISO/IEC 2020 – All rights reserved
v
Introduction
This document specifies requirements and implementation guidelines for the compressed representation of
digital images for storage and interchange in a form referred to as JPEG XR. The JPEG XR design provides a
practical coding technology for a broad range of applications with excellent compression capability and important
additional functionalities. An input image is typically operated on by an encoder to create a JPEG XR coded image.
The decoder then operates on the coded image to produce an output image that is either an exact or approximate
reconstruction of the input image.
The primary intended application of JPEG XR is the representation of continuous-tone still images such as
photographic images. The manner of representation of the compressed image data and the associated decoding
process are specified. These processes and representations are generic, that is, they are applicable to a broad
range of applications using compressed colour and grayscale images in communications and computer systems
and within embedded applications, including mobile devices.
As of 2008, the most widely used digital photography format is a nominal implementation of the first JPEG coding
format as specified in ITU-T Recommendation T.81 | ISO/IEC 10918-1. This encoding uses a bit depth of 8 for each
of three channels, resulting in 256 representable values per channel (a total of 16 777 216 representable colour
values).
More demanding applications may require a bit depth of 16, providing 65 536 representable values for each
colour values. Additional scenarios may necessitate even greater bit
channel, and resulting in over 2.8 * 10
depths and sample representation formats. When memory or processing power is at a premium, as few as five or
six bits per channel may be used.
The JPEG XR specification enables greater effective use of compressed imagery with this broadened diversity of
application requirements. JPEG XR supports a wide range of colour encoding formats including monochrome, RGB,
CMYK an
...