ISO/IEC 23091-2:2025

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
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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Email: copyright@iso.org
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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:// www .electropedia .org/
3.1
bottom field
assembly of the odd-numbered rows of samples of the components (3.3) of a video frame using a numbering
of rows that starts with row number 0 as the top row
3.2
chroma
sample array or single sample representing one of the two colour difference signals related to the primary
colours, represented by the symbols Cb and Cr
Note 1 to entry: The term "chroma" is used rather than "chrominance" in order to avoid the implication of the use of
linear light transfer characteristics that is often associated with "chrominance".
3.3
component
array or single sample from one of the three arrays [luma (3.4) and two chroma (3.2)] that compose a picture
(3.5) in 4:2:0, 4:2:2, or 4:4:4 colour format or the array or a single sample of the array that compose a picture
in monochrome format
© ISO/IEC 2025 – All rights reserved
3.4
luma
sample array or single sample representing the monochrome signal related to the primary colours,
represented by the symbol or subscript Y or L
Note 1 to entry: The term "luma" is used rather than "luminance" in order to avoid the implication of the use of linear
light transfer characteristics that is often associated with "luminance". The symbol L is sometimes used instead of the
symbol Y to avoid confusion with the symbol y as used for vertical location.
3.5
picture
array of luma (3.4) samples in monochrome format or array of luma samples and two corresponding arrays
of chroma (3.2) samples in 4:2:0, 4:2:2, and 4:4:4 colour format
3.6
reserved
values of a particular code point that are for future use by ITU-T | ISO/IEC
Note 1 to entry: These values shall not be used in identifiers conforming to this edition of this document. It is possible
they will be used in a manner yet to be specified in some future extensions of this document by ITU-T | ISO/IEC.
3.7
top field
assembly of the even-numbered rows of samples of the components (3.3) of a video frame using a numbering
of rows that starts with row number 0 as the top row
3.8
unspecified
values of a particular code point that have no specified meaning in this edition of this document and will not
have a specified meaning in the future as an integral part of future editions of this document
4 Abbreviated terms
LSB least significant bit
MSB most significant bit
SAR sample aspect ratio
SMPTE Society of Motion Picture and Television Engineers
5 Conventions
NOTE The mathematical operators used in the pseudocode operations specified in this document are similar to
those used in the C programming language. However, integer division and arithmetic shift operations are specifically
defined. Numbering and counting conventions generally begin from 0.
5.1 Arithmetic operators
+ addition
− subtraction (as a two-argument operator) or negation (as a unary prefix operator)
* multiplication, including matrix multiplication
exponentiation, x to the power of y (in other contexts, such notation may be used for superscripting
y
x
not intended for interpretation as exponentiation)

© ISO/IEC 2025 – All rights reserved
integer division with truncation of the result toward zero (for example, 7 / 4 and (−7) / (−4) are
/
truncated to 1 and (−7) / 4 and 7 / (−4) are truncated to −1)
÷ division in mathematical expressions where no truncation or rounding is intended
x
division in mathematical expressions where no truncation or rounding is intended
y
y
summation of f( i ) with i taking all integer values from x up to and including y
fi()
∑
ix=
x % y modulus, remainder of x divided by y, defined only for integers x and y with x >= 0 and y > 0
5.2 Bit-wise operators
bit-wise "and" (when operating on integer arguments, operates on a two's complement
& representation of the integer value; when operating on a binary argument that contains fewer bits
than another argument, the shorter argument is extended by adding more significant bits equal to 0)
bit-wise "or" (when operating on integer arguments, operates on a two's complement
| representation of the integer value; when operating on a binary argument that contains fewer bits
than another argument, the shorter argument is extended by adding more significant bits equal to 0)
bit-wise "exclusive or" (when operating on integer arguments, operates on a two's
complement representation of the integer value; when operating on a binary argument that contains
^
fewer bits than another argument, the shorter argument is extended by adding more significant
bits equal to 0)
arithmetic right shift of a two's complement integer representation of x by y binary digits (defined
x >> y only for non-negative integer values of y; bits shifted into the MSBs as a result of the right shift
have a value equal to the MSB of x prior to the shift operation)
arithmetic left shift of a two's complement integer representation of x by y binary digits (defined
x << y only for non-negative integer values of y; bits shifted into the LSBs as a result of the left shift have
a value equal to 0)
5.3 Assignment operators
= assignment operator
increment, i.e. x++ is equivalent to x = x + 1; when used in an array index, evaluates to the value
++
of the variable prior to the increment operation
decrement, i.e. x− − is equivalent to x = x − 1; when used in an array index, evaluates to the value
− −
of the variable prior to the decrement operation
increment by amount given, i.e. x += 3 is equivalent to x = x + 3, and x += (−3) is equivalent to
+=
x = x + (−3)
decrement by amount given, i.e. x −= 3 is equivalent to x = x − 3, and x −= (−3) is equivalent to
−=
x = x − (−3)
© ISO/IEC 2025 – All rights reserved
5.4 Relational, logical, and other operators
= = equality operator
!= not equal to operator
!x logical negation "not"
> larger than operator
< smaller than operator
>= larger than or equal to operator
<= smaller than or equal to operator
conditional/logical "and" operator, performs a logical "and" of its Boolean operators, but only
&&
evaluates the second operand when necessary
conditional/logical "or" operator, performs a logical "or" of its Boolean operators, but only evalu-
| |
ates the second operand when necessary
ternary conditional, if condition a is true, then the result is equal to b; otherwise the result is
a ? b : c
equal to c
NOTE When a relational operator is applied to a code point or variable that has been assigned the value "na" (not
applicable), the value "na" is treated as a distinct value for the code point or variable. The value "na" is considered not
to be equal to any other value.
5.5 Mathematical functions
Pseudocode operations (1) to (10) specify functions for use in the pseudocode logic within this document.
x; x >= 0

Absx = (1)
()

−x; x < 0

Clip1 ( x ) = Clip3( 0, ( 1 << BitDepth ) − 1, x ), (2)
Y Y
where BitDepth is the representation bit depth of the corresponding luma colour component signal.
Y
Clip1 ( x ) = Clip3( 0, ( 1 << BitDepth ) − 1, x ), (3)
C C
where BitDepth is the representation bit depth of the corresponding chroma colour component signal
C
C. In general, BitDepth may be distinct for different chroma colour components signals C – e.g. for C
C
corresponding to Cb or Cr.
xz; 

Clip3( x, y, z ) = yz; >y (4)


zo; therwise

Floor( x ) is the largest integer less than or equal to x. (5)
Ln( x ) is the natural logarithm of x. (6)
Log10( x ) is the base-10 logarithm of x. (7)
Round( x ) = Sign( x ) * Floor( Abs( x ) + 0.5 ). (8)

© ISO/IEC 2025 – All rights reserved
1; x > 0


Sign()x= 0; x = = 0 (9)


−1; x < 0

Sqrt( x ) is the square root of x. (10)
5.6 Order of operations
When order of precedence in an expression is not indicated explicitly by use of parentheses, the following
rules apply:
— Operations of a higher precedence are evaluated before any operation of a lower precedence.
— Operations of the same precedence are evaluated sequentially from left to right.
Table 1 specifies the precedence of operations from highest to lowest; a higher position in the table indicates
a higher precedence.
NOTE For those operators that are also used in the C programming language, the order of precedence used in this
document is the same as used in the C programming language.
Table 1 — Operation precedence from highest (at top of table) to lowest (at bottom of table)
Operations (with operands x, y, and z)
"x++", "x− −"
"!x", "−x" (as a unary prefix operator)
y
"x "
x
"x * y", "x / y", "x ÷ y", " ", "x % y"
y
y
"x + y", "x − y" (as a two-argument operator), " fi "
()
∑
ix=
"x << y", "x >> y"
"x < y", "x <= y", "x > y", "x >= y"
"x = = y", "x != y"
"x & y"
"x | y"
"x && y"
"x | | y"
"x ? y : z"
"x = y", "x += y", "x −= y"
6 Specified code points
This clause identifies the code points defined in this document, as listed in Table 2 with cross-references to
the subclause in which each is specified.

© ISO/IEC 2025 – All rights reserved
Table 2 — List of code point definitions
Name Abstract Subclause
ColourPrimaries Video colour primaries 8.1
TransferCharacteristics Video colour transfer characteristics 8.2
MatrixCoefficients and VideoFullRangeFlag Video matrix colour coefficients 8.3
VideoFramePackingType and QuincunxSamplingFlag Video frame packing 8.4
PackedContentInterpretationType Interpretation of packed video frames 8.5
SampleAspectRatio, SarWidth, and SarHeight Sample aspect ratio of video 8.6
Chroma sampling grid alignment for video 8.7
Chroma420SampleLocType fields or frames having the 4:2:0 colour
format
7 Principles for definition and referencing of code points
7.1 Application usage
This document specifies code points for coding-independent description of video and image signal type
characteristics. These signal type identifiers can be used to provide universal descriptions to assist the
interpretation of signals following decoding or to describe properties of the signals prior to encoding.
An example of the usage of the code point identifiers specified in this document is illustrated in Figure 1.
The signal type identifier may be represented within the video elementary stream produced by an encoder.
Alternatively, or additionally, the signal type identifier may be carried outside of a video elementary stream
by other means, such as in a file storage format, in a system multiplex format, or in a streaming system
protocol.
Figure 1 — Example usage
Further information on the usage of video signal type code points, including the identification of code
point combinations that are widely used in production and video content workflows, is available in ITU-T
H-Suppl. 19 | ISO/IEC TR 23091-4.
7.2 Code point encoding and defaults
The code points defined herein may be specified as a value or a label of an enumerated list. The definition of
their encoding and representation (e.g. as a binary number) is the responsibility of the specification using the
code point, as is the identification of any applicable default value not specified herein. It is also possible for
external specifications to use a mapping to values defined here, if they wish to preserve identical semantics
but different code point assignments.
Guidance is given for each code point as to a suitable type (e.g. unsigned integer) and a suitable value range
(e.g. 0 to 63, inclusive) for assistance in writing derived specifications. In some instances, default flag values
are provided that are suggested to be inferred for code point parameters with associated flags that might
not be explicitly signalled or specified in derived specifications.

© ISO/IEC 2025 – All rights reserved
7.3 Externally defined values
If the external specification permits values not defined by this document to be identified in the same field
that carries values defined by this document, then that other specification shall identify how values defined
herein can be distinguished from values not defined herein.
7.4 Reference format
References to code points in this document should use only the code point name (i.e. a "Name" from Table 2)
and specification title, and not use subclause numbers or any other "fragile" reference such as a table
number. For example, for a hypothetical code point named "ChocolateDensity", a document can refer to
"ChocolateDensity as defined in Rec. ITU-T H.273 | ISO/IEC 23091-2".
7.5 Uniform resource name format
ISO/IEC 23091-1 specifies a uniform resource name format that may be used for the code points specified in
this document.
8 Video code points
8.1 Colour primaries
Type: Unsigned integer, enumeration
Range: 0 to 255, inclusive
ColourPrimaries indicates the chromaticity coordinates of the source colour primaries as specified
in Table 3 in terms of the CIE 1931 definition of x and y, which shall be interpreted as specified by
ISO/CIE 11664-1.
An 8-bit field should be adequate for representation of the ColourPrimaries code point.
Table 3 — Interpretation of colour primaries (ColourPrimaries) value
Value Colour primaries Informative remarks
0 Reserved For future use by ITU-T | ISO/IEC
1 primary x y Rec. ITU-R BT.709-6
Rec. ITU-R BT.1361-0 conventional colour gamut
green 0.300 0.600
system and extended colour gamut system
blue 0.150 0.060
(historical)
red 0.640 0.330
IEC 61966-2-1 sRGB or sYCC
white D65 0.3127 0.3290
IEC 61966-2-4
SMPTE RP 177 (1993) Annex B
2 Unspecified Image characteristics are unknown or are
determined by the application.
3 Reserved For future use by ITU-T | ISO/IEC
4 primary x y Rec. ITU-R BT.470-6 System M (historical)
United States National Television System
green 0.21 0.71
Committee 1953 Recommendation for
blue 0.14 0.08
transmission standards for colour television
red 0.67 0.33
United States Federal Communications
Commission Title 47 Code of Federal Regulations
white C 0.310 0.316
(2003) 73.682 (a) (20)
© ISO/IEC 2025 – All rights reserved
TTabablele 3 3 ((ccoonnttiinnueuedd))
Value Colour primaries Informative remarks
5 primary x y Rec. ITU-R BT.470-6 System B, G (historical)
Rec. ITU-R BT.601-7 625
green 0.29 0.60
Rec. ITU-R BT.1358-0 625 (historical)
blue 0.15 0.06
Rec. ITU-R BT.1700-0 625 PAL and 625 SECAM
red 0.64 0.33
white D65 0.3127 0.3290
6 primary x y Rec. ITU-R BT.601-7 525
Rec. ITU-R BT.1358-1 525 or 625 (historical)
green 0.310 0.595
Rec. ITU-R BT.1700-0 NTSC
blue 0.155 0.070
SMPTE ST 170 (2004)
red 0.630 0.340
(functionally the same as the value 7)
white D65 0.3127 0.3290
7 primary x y SMPTE ST 240 (1999)
(functionally the same as the value 6)
green 0.310 0.595
blue 0.155 0.070
red 0.630 0.340
white D65 0.3127 0.3290
8 primary x y Generic film (colour filters using Illuminant C)
green 0.243 0.692 (Wratten 58)
blue 0.145 0.049 (Wratten 47)
red 0.681 0.319 (Wratten 25)
white C 0.310 0.316
9 primary x y Rec. ITU-R BT.2020-2
Rec. ITU-R BT.2100-2
green 0.170 0.797
blue 0.131 0.046
red 0.708 0.292
white D65 0.3127 0.3290
10 primary x y SMPTE ST 428-1 (2019)
(CIE 1931 XYZ as in ISO/CIE 11664-1)
green (Y) 0.0 1.0
blue (Z) 0.0 0.0
red (X) 1.0 0.0
centre white 1 ÷ 3 1 ÷ 3
11 primary x y SMPTE RP 431-2 (2011)
green 0.265 0.690
blue 0.150 0.060
red 0.680 0.320
white 0.314 0.351
12 primary x y SMPTE EG 432-1 (2010)
green 0.265 0.690
blue 0.150 0.060
red 0.680 0.320
white D65 0.3127 0.3290
13 to 21 Reserved For future use by ITU-T | ISO/IEC

© ISO/IEC 2025 – All rights reserved
TTabablele 3 3 ((ccoonnttiinnueuedd))
Value Colour primaries Informative remarks
22 primary x y No corresponding industry specification identified
green 0.295 0.605
blue 0.155 0.077
red 0.630 0.340
white D65 0.3127 0.3290
23 to 255 Reserved For future use by ITU-T | ISO/IEC
8.2 Transfer characteristics
Type: Unsigned integer, enumeration
Range: 0 to 255, inclusive
TransferCharacteristics, as specified in Table 4, either indicates the reference opto-electronic transfer
characteristic function of the source picture as a function of a source input linear optical intensity input
L with a nominal real-valued range of 0 to 1, inclusive, or indicates the inverse of the reference electro-
c
optical transfer characteristic function as a function of an output linear optical intensity L with a nominal
o
real-valued range of 0 to 1, inclusive. For interpretation of entries in Table 4 that are expressed in terms
of multiple curve segments parameterized by the variable α over a region bounded by the variable β or
by the variables β and γ, the values of α and β are defined to be the positive constants necessary for the
curve segments that meet at the value β to have continuity of both value and slope at the value β. The value
of γ, when applicable, is defined to be the positive constant necessary for the associated curve segments
to meet at the value γ. For example, for TransferCharacteristics equal to 1, 6, 14, or 15, α has the value
1 + 5.5* β = 1.099 296 826 809 442. and β has the value 0.018 053 968 510 807.
An 8-bit field should be adequate for representation of the TransferCharacteristics code point.
NOTE 1 As indicated in Table 4, some values of TransferCharacteristics are defined in terms of a reference opto-
electronic transfer characteristic function and others are defined in terms of a reference electro-optical transfer
characteristic function, according to the convention that has been applied in other documents. In the cases of Rec.
ITU-R BT.709-6 and Rec. ITU-R BT.2020-2 (as can be indicated by TransferCharacteristics equal to 1, 6, 14, or 15),
although the value is defined in terms of a reference opto-electronic transfer characteristic function, a corresponding
reference electro-optical transfer characteristic function for flat panel displays used in HDTV studio production has
been specified in Rec. ITU-R BT.1886-0.
Depending on the application and for proper functioning of the pseudocode operations specified in
this document, it is possible that certain combinations of TransferCharacteristics, VideoFullRangeFlag,
BitDepth , and BitDepth will not be permitted.
Y C
© ISO/IEC 2025 – All rights reserved
Table 4 — Interpretation of transfer characteristics (TransferCharacteristics) value
Value Transfer characteristics Informative remarks
0 Reserved For future use by ITU-T | ISO/IEC
0.45
1 V = α * L − ( α − 1 ) for 1 >= L >= β Rec. ITU-R BT.709-6
c c
V = 4.500 * L for β > L >= 0 Rec. ITU-R BT.1361-0 convention-
c c
al colour gamut system (histor-
ical)
(functionally the same as the
values 6, 14, and 15)
2 Unspecified Image characteristics are un-
known or are determined by the
application.
3 Reserved For future use by ITU-T | ISO/IEC
4 Assumed display gamma 2.2 Rec. ITU-R BT.470-6 System M
(historical)
United States National Television
System Committee 1953 Rec-
ommendation for transmission
standards for colour television
United States Federal Communi-
cations Commission Title 47 Code
of Federal Regulations (2003)
73.682 (a) (20)
Rec. ITU-R BT.1700-0 625 PAL
and 625 SECAM
5 Assumed display gamma 2.8 Rec. ITU-R BT.470-6 System B, G
(historical)
0.45
6 V = α * L − ( α − 1 ) for 1 >= L >= β Rec. ITU-R BT.601-7 525 or 625
c c
V = 4.500 * L for β > L >= 0 Rec. ITU-R BT.1358-1 525 or 625
c c
(historical)
Rec. ITU-R BT.1700-0 NTSC
SMPTE ST 170 (2004)
(functionally the same as the
values 1, 14, and 15)
0.45
7 V = α * L − ( α − 1 ) for 1 >= L >= β SMPTE ST 240 (1999)
c c
V = 4.0 * L for β > L >= 0
c c
8 V = L for 1 > L >= 0 Linear transfer characteristics
c c
9 V = 1.0 + Log10( L ) ÷ 2 for 1 >= L >= 0.01 Logarithmic transfer characteris-
c c
tic (100 to 1 range)
V = 0.0 for 0.01 > L >= 0
c
10 V = 1.0 + Log10( L ) ÷ 2.5 for 1 >= L >= Logarithmic transfer characteris-
c c
Sqrt( 10 ) ÷ 1000 tic (100 * Sqrt( 10 ) to 1 range)
V = 0.0
for Sqrt( 10 ) ÷ 1000 > L
c
>= 0
0.45
11 V = α * L − ( α − 1 ) for L >= β IEC 61966-2-4
c c
V = 4.500 * L for β > L > −β
c c
0.45
V = −α * ( −L ) + ( α − 1 ) for −β >= L
c c
0.45
12 V = α * L − ( α − 1 ) for 1.33 > L >= β Rec. ITU-R BT.1361-0 extended
c c
colour gamut system (historical)
V = 4.500 * L for β > L >= −γ
c c
0.45
V = −( α * ( −4 * L ) − ( α − 1 ) ) ÷ 4 for −γ >= L >= −0.25
c c
© ISO/IEC 2025 – All rights reserved
TTabablele 4 4 ((ccoonnttiinnueuedd))
Value Transfer characteristics Informative remarks
13 —  If MatrixCoefficients is equal to 0 IEC 61966-2-1 sRGB (with Matrix-
( 1÷2.4 )
Coefficients equal to 0)
V = α * L − ( α − 1 ) for 1 > L >= β
c c
IEC 61966-2-1 sYCC (with Matrix-
V = 12.92 * L for β > L >= 0
c c
Coefficients equal to 5)
—  Otherwise
( 1÷2.4 )
V = α * L − ( α − 1 ) for L >= β
c c
V = 12.92 * L for β > L > −β
c c
( 1÷2.4 )
V = −α * ( −L ) + ( α − 1 ) for −β >= L
c c
0.45
14 V = α * L − ( α − 1 ) for 1 >= L >= β Rec. ITU-R BT.2020-2
c c
V = 4.500 * L for β > L >= 0 (functionally the same as the
c c
values 1, 6, and 15)
0.45
15 V = α * L − ( α − 1 ) for 1 >= L >= β Rec. ITU-R BT.2020-2
c c
V = 4.500 * L for β > L >= 0 (functionally the same as the
c c
values 1, 6, and 14)
n n m
16 V = ( ( c + c * L ) ÷ ( 1 + c * L ) ) for all values of L SMPTE ST 2084 (2014) for 10, 12,
1 2 o 3 o o
14, and 16-bit systems
c = c − c + 1 = 107 ÷ 128
1 3 2
= 0.835 937 5 Rec. ITU-R BT.2100-2 perceptual
quantization (PQ) system
c = 2413 ÷ 128 = 18.851 562 5
c = 2392 ÷ 128 = 18.687 5
m = 2523 ÷ 32 = 78.843 75
n = 1305 ÷ 8192 = 0.159 301 757 812 5
for which L equal to 1 for peak white is ordinarily intended to cor-
o
respond to a reference output luminance level of 10 000 candelas per
square metre
( 1 ÷ 2.6 )
17 V = ( 48 * L ÷ 52.37 ) for all values of L SMPTE ST 428-1 (2019)
o o
for which L equal to 1 for peak white is ordinarily intended to
o
correspond to a reference output luminance level of 48 candelas per
square metre
18 V = a * Ln( 12 * L − b ) + c for 1 >= L > 1 ÷ 12 Association of Radio Industries
c c
0.5
and Businesses (ARIB) STD-B67
V = Sqrt( 3 ) * L for 1 ÷ 12 >= L >= 0
c c
(2018)
a = 0.178 832 77
Rec. ITU-R BT.2100-2 hybrid
b = 0.284 668 92
log-gamma (HLG) system
c = 0.559 910 73
19 to 255 Reserved For future use by ITU-T | ISO/IEC
NOTE 2 For TransferCharacteristics equal to 13, the pseudocode operations given in Table 4 for interpretation with
MatrixCoefficients equal to 0 were specified as applying to all values of MatrixCoefficients in a previous edition of
this document. Closer study later determined that IEC 61966-2-1 had specified a wider range of values for L in the
c
context of sYCC usage corresponding to MatrixCoefficients equal to 5. This document was therefore revised to provide
a specification of TransferCharacteristics interpretation that depends on the value of MatrixCoefficients to address
this deficiency in the previous edition of the document.
NOTE 3 For TransferCharacteristics equal to 18, the pseudocode operations given in Table 4 are normalized for
a source input linear optical intensity L with a nominal real-valued range of 0 to 1, inclusive. An alternative scaling
c
[26]
that is mathematically equivalent is used in ARIB STD-B67 with the source input linear optical intensity having a
nominal real-valued range of 0 to 12, inclusive.
8.3 Matrix coefficients
Type: Unsigned integer, enumeration
Range: 0 to 255, inclusive, plus associated flag
MatrixCoefficients describes the matrix coefficients used in deriving luma and chroma signals from the
green, blue, and red, or X, Y, and Z primaries, as specified in Table 5 and the pseudocode logic expressions
specified below.
© ISO/IEC 2025 – All rights reserved
A flag, VideoFullRangeFlag, may be supplied with this code point (see below).
VideoFullRangeFlag specifies the scaling and offset values applied in association with the MatrixCoefficients.
When not present or not specified, the value 0 for VideoFullRangeFlag would ordinarily be inferred as the
default value for video imagery.
An 8-bit field should be adequate for representation of the MatrixCoefficients code point.
Certain values of MatrixCoefficients may be disallowed, depending on the application and the characteristics
and format of the signal, e.g. with regard to combinations of the chroma format sampling structure and the
values of BitDepth and BitDepth .
Y C
The interpretation of MatrixCoefficients is specified by the following pseudocode logic. E , E , and E are
R G B
defined as "linear-domain" real-valued signals based on the indicated colour primaries (see 8.1) before
applying the transfer characteristics (see 8.2).
For purposes of the YZX representation when MatrixCoefficients is equal to 0, the symbols R, G, and B are
substituted for X, Y, and Z, respectively, in pseudocode operations (11) to (19), (27) to (29), and (33) to (35),
and (48) to (50).
Nominal peak white is specified as having E equal to 1, E equal to 1, and E equal to 1.
R G B
Nominal black is specified as having E equal to 0, E equal to 0, and E equal to 0.
R G B
The application of the transfer characteristics function is denoted by ( x )′ for an argument x.
— If MatrixCoefficients is not equal to 14 or 15, the signals E′ , E′ , and E′ are determined by application
R G B
of the transfer characteristics function as per pseudocode operations (11) to (13):
E′ = (E )′ (11)
R R
E′ = (E )′ (12)
G G
E′ = (E )′ (13)
B B
In this case, the range of E′ , E′ , and E′ is specified as follows:
R G B
— If TransferCharacteristics is equal to 11 or 12, or TransferCharacteristics is equal to 13 and
MatrixCoefficients is not equal to 0, E′ , E′ , and E′ are real numbers with values that have a
R G B
larger range than the range of 0 to 1, inclusive, and their range is not specified in this document.
— Otherwise, E′ , E′ , and E′ are real numbers in the range of 0 to 1, inclusive.
R G B
— Otherwise (MatrixCoefficients is equal to 14 or 15), the signals E′ , E′ , and E′ are determined by the
L M S
following ordered pseudocode steps:
a) The "linear-domain" real-valued signals E , E , and E are determined as follows:
L M S
— If MatrixCoefficients is equal to 14, pseudocode operations (14) to (16) apply:
E = ( 1 688 * E + 2 146 * E + 262 * E ) ÷ 4 096 (14)
L R G B
E = ( 683 * E + 2 951 * E + 462 * E ) ÷ 4 096 (15)
M R G B
E = ( 99 * E + 309 * E + 3 688 * E ) ÷ 4 096 (16)
S R G B
— Otherwise (MatrixCoefficients is equal to 15), pseudocode operations (17) to (19) apply:

© ISO/IEC 2025 – All rights reserved
E = ( 1 747 * E + 2 169 * E + 180 * E ) ÷ 4 096 (17)
L R G B
E = ( 673 * E + 3 029 * E + 394 * E ) ÷ 4 096 (18)
M R G B
E = ( 50 * E + 207 * E + 3 839 * E ) ÷ 4 096 (19)
S R G B
b) The signals E′ , E′ , and E′ are determined by application of the transfer characteristics func-
L M S
tion as per pseudocode operations (20) to (22):
E′ = (E )′ (20)
L L
E′ = (E )′ (21)
M M
E′ = (E )′ (22)
S S
When MatrixCoefficients is equal to 0, 8, 16, or 17, the variables BitDepth and MaxVal are derived
RGB RGB
using the following ordered pseudocode steps:
a) The variable BitDepth is derived as follows:
RGB
— If MatrixCoefficients is equal to 0 or 8, the following applies:
BitDepth = BitDepth (23)
RGB Y
— Otherwise, if MatrixCoefficients is equal to 16, the following applies:
BitDepth = BitDepth − 2 (24)
RGB Y
— Otherwise (MatrixCoefficients is equal to 17), the following applies:
BitDepth = BitDepth − 1 (25)
RGB Y
b) The variable MaxVal is derived as follows:
RGB
MaxVal = ( 1 << BitDepth ) − 1 (26)
RGB RGB
The interpretation of MatrixCoefficients is specified as follows.
— If VideoFullRangeFlag is equal to 0, the following applies:
— If MatrixCoefficients is equal to 0, 8, 16, or 17, pseudocode operations (25) to (27) apply:
R = Clip3( 0, MaxVal , ( 1 << ( BitDepth − 8 ) ) * ( 219 * E′ + 16 ) ) (27)
RGB RGB R
G = Clip3( 0, MaxVal , ( 1 << ( BitDepth − 8 ) ) * ( 219 * E′ + 16 ) ) (28)
RGB RGB G
B = Clip3( 0, MaxVal , ( 1 << ( BitDepth − 8 ) ) * ( 219 * E′ + 16 ) ) (29)
RGB RGB B
NOTE 1 Pseudocode operations (27) to (29) are drafted under the assumption that BitDepth is greater than or
RGB
equal to 8.
© ISO/IEC 2025 – All rights reserved
— Otherwise, if MatrixCoefficients is equal to 1, 4, 5, 6, 7, 9, 10, 11, 12, 13, or 14, pseudocode op-
erations (30) to (32) apply:
Y = Clip1 ( Round( ( 1 << (BitDepth − 8 ) ) * ( 219 * E′ + 16 ) ) ) (30)
Y Y Y
Cb = Clip1 ( Round( ( 1 << (BitDepth − 8 ) ) * ( 224 * E′ + 128 ) ) ) (31)
C C PB
Cr = Clip1 ( Round( ( 1 << (BitDepth − 8 ) ) * ( 224 * E′ + 128 ) ) ) (32)
C C PR
NOTE 2 Pseudocode operations (30) to (32) are drafted under the assumption that BitDepth and BitDepth are
Y C
greater than or equal to 8.
— Otherwise, if MatrixCoefficients is equal to 2, the interpretation of the MatrixCoefficients code
point is unknown or is determined by the application.
— Otherwise (MatrixCoefficients is not equal to 0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, or 17),
the interpretation of the MatrixCoefficients code point is reserved for future definition by
ITU-T | ISO/IEC.
— Otherwise (VideoFullRangeFlag is equal to 1), the following pseudocode logic applies:
— If MatrixCoefficients is equal to 0,
...