ISO/IEC 23091-2:2025
(Main)Information technology — Coding-independent code points — Part 2: Video
Information technology — Coding-independent code points — Part 2: Video
This document defines various code points and fields that establish properties of a video (or still image) representation and are independent of the compression encoding and bit rate. These properties can describe the appropriate interpretation of decoded data or can, similarly, describe the characteristics of such a signal before the signal is compressed by an encoder that is suitable for compressing such an input signal.
Technologies de l'information — Points de code indépendants du codage — Partie 2: Vidéo
General Information
Relations
Standards Content (Sample)
International
Standard
ISO/IEC 23091-2
Third edition
Information technology — Coding-
2025-02
independent code points —
Part 2:
Video
Technologies de l'information — Points de code indépendants du
codage —
Partie 2: Vidéo
Reference number
© ISO/IEC 2025
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© ISO/IEC 2025 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Conventions . 2
5.1 Arithmetic operators .2
5.2 Bit-wise operators .3
5.3 Assignment operators .3
5.4 Relational, logical, and other operators .4
5.5 Mathematical functions .4
5.6 Order of operations .5
6 Specified code points. 5
7 Principles for definition and referencing of code points . 6
7.1 Application usage .6
7.2 Code point encoding and defaults .6
7.3 Externally defined values .7
7.4 Reference format .7
7.5 Uniform resource name format .7
8 Video code points . 7
8.1 Colour primaries .7
8.2 Transfer characteristics .9
8.3 Matrix coefficients .11
8.4 Video frame packing type .19
8.5 Packed video content interpretation .24
8.6 Sample aspect ratio .24
8.7 Chroma 4:2:0 sample location type . 26
Bibliography .29
© ISO/IEC 2025 – 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.
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 or www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had not
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
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, in collaboration with
ITU-T [as Rec. ITU-T H.273 (07/2024)].
This third edition cancels and replaces the second edition (ISO/IEC 23091-2:2021), which has been
technically revised.
The main changes are as follows:
— correction of the range of values for analogue colour primary signals for the sYCC colour representation
specified in IEC 61966-2-1;
— addition of a colour representation developed in the Society of Motion Picture and Television Engineers
that is referred to as IPT-C2;
— specification of code point identifiers, referred to as YCgCo-Re and YCgCo-Ro, for YCoCg-R colour
representation with equal luma and chroma bit depths, where the number of bits added to a source
RGB bit depth is 2 (i.e. even) and 1 (odd), respectively, as indicated by the “e” and “o” appended to the
abbreviated names;
A list of all parts in the ISO/IEC 23091 series can be found on the ISO and IEC websites.
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 and
www.iec.ch/national-committees.
© ISO/IEC 2025 – All rights reserved
iv
Introduction
In a number of specifications, there is a need to identify some characteristics of video (or still image) media
content that are logically independent of the compression format. These characteristics can include, for
example, aspects that relate to the sourcing or presentation, or the role of the video (or still image) media
component. These characteristics have typically been documented by fields that take an encoded value or
item selected from an enumerated list, herein called code points.
These code points are typically defined in the specification of compression formats to document these
characteristics of the media. In past practices, the definition of these fields has been copied from document
to document, sometimes with new values being added in later documents (and sometimes with later
amendments specified to add new entries to existing documents).
This past practice has raised a number of issues, including the following:
a) A lack of a formal way to avoid conflicting assignments being made in different documents.
b) Having additional values defined in later specifications that can be practically used with older
compression formats, but without clear formal applicability of these new values to older documents.
c) Any update or correction of code point semantics can incur significant effort to update all documents
in which the code point is specified, instead of enabling a single central specification to apply across
different referencing specifications.
d) The choice of reference for other specifications (such as container or delivery formats) not being obvious;
wherein a formal reference to a compression format document appears to favour that one format over
others, and also appears to preclude definitions defined in other compression format specifications.
e) Burdensome maintenance needs to ensure that a reference to material defined in a compression format
specification is maintained appropriately over different revisions of the referenced format specification,
as the content of a compression format specification can change over time and is ordinarily not intended
as a point of reference for defining such code points.
This document provides a central definition of such code points for video and image applications to address
these issues. This document can be used to provide universal descriptions to assist interpretation of video
and image signals following decoding, or to describe the properties of these signals before they are encoded.
© ISO/IEC 2025 – All rights reserved
v
International Standard ISO/IEC 23091-2:2025(en)
Information technology — Coding-independent code
points —
Part 2:
Video
1 Scope
This document defines various code points and fields that establish properties of a video (or still image)
representation and are independent of the compression encoding and bit rate. These properties can describe
the appropriate interpretation of decoded data or can, similarly, describe the characteristics of such a signal
before the signal is compressed by an encoder that is suitable for compressing such an input signal.
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/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https
...
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