IEC 61966-12-2:2024

Multimedia systems and equipment - Colour measurement and management - Part 12-2: Simple metadata format for identification of colour gamut

IEC 61966-12-2:2024 specifies the colour gamut metadata format for video systems intended for use in CE (consumer electronics) devices. The metadata specified in this part of IEC 61966-12 is limited to the gamut description for display types comprising the three primary additive colours, whose white and black points have the same chromaticity. It is fundamentally based on the conventional VESA-EDID format.
When associated with content, the simple metadata format defines the gamut for which the content was created. It can be used by the display for controlled colour reproduction even if the display’s colour gamut is different from that of the content. When associated with a display, the simple metadata format defines the display colour gamut. It can be used during content creation to enable improved colour reproduction.
This document provides the simplest, but unambiguous solution for typical CE devices that are based on colour gamut information communication.
IEC 61966-12-2:2024 cancels and replaces the first edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the number of bits of metadata format has been extended in Clause 4;
b) Annex C has been added for handling HDR content.

General Information

• Status: Published
• Publication Date: 21-Oct-2024
• ICS: 17.180.20 - Colours and measurement of light
• ICS: 33.160.40 - Video systems
• Technical Committee: TA 2 - Colour measurement and management
• Drafting Committee: MT 61966-12-2 - TC 100/TA 2/TA 2/MT 61966-12-2
• Current Stage: PPUB - Publication issued
• Start Date: 22-Oct-2024
• Completion Date: 08-Nov-2024

Relations

• Revises: IEC 61966-12-2:2014 - Multimedia systems and equipment - Colour measurement and management - Part 12-2: Simple metadata format for identification of colour gamut
• Effective Date: 05-Sep-2023

Overview

IEC 61966-12-2:2024 - "Multimedia systems and equipment - Colour measurement and management - Part 12-2: Simple metadata format for identification of colour gamut" - defines a compact, unambiguous metadata format to identify the colour gamut for video systems targeted at consumer electronics (CE) devices. The standard is a technical revision of the 2014 edition and is fundamentally based on the conventional VESA-EDID format. It provides a lightweight Gamut ID suitable for displays and content that use three primary additive colours whose white and black points share the same chromaticity.

Key topics and technical requirements

• Simple gamut description: Encodes the chromaticities of the three primaries (R, G, B) plus white using CIE-xy values in a fixed-point representation derived from VESA-EDID.
• Encoding details:
  • CIE-xy values for R, G, B and white are provided in a 10-bit fixed-point form (range 0.0–1.0).
  • White Absolute Luminance (WAL) is encoded as a 16-bit unsigned integer (cd/m²).
  • Black Level Ratio (BLR) is encoded as a 32-bit fixed-point value (range 0.0–1.0).
• Assumptions and scope:
  • Intended only for device types with three additive primaries and identical white/black chromaticity.
  • Designed for CE devices with limited CPU/software resources - provides the simplest unambiguous metadata profile for interoperability.
• Updates in 2024 edition:
  • Extended number of bits in metadata (Clause 4) to better support wider dynamic ranges.
  • Annex C added to address handling of HDR content.
• Interoperability: Works when associated with either content (to describe content creation gamut) or displays (to describe device gamut), enabling controlled colour reproduction and improved gamut mapping.

Applications and who uses it

• CE manufacturers (TVs, set-top boxes, projectors, monitors): embed or read simple Gamut ID metadata to improve out-of-box colour reproduction.
• Content creators and post-production houses: tag video with the gamut for which content was authored to guide display rendering.
• Display engineers and color management system developers: implement simplified gamut exchange in devices with limited processing resources.
• Streaming services and broadcasters: include lightweight gamut metadata with delivered content to ensure more predictable colour across diverse displays, including HDR-aware workflows.

Related standards

• IEC 61966-12-1 - Metadata for identification of colour gamut (full/medium/simple profiles)
• VESA EDID - EDID structure used as a basis for CIE-xy encoding
• Video colour and HDR standards referenced in IEC guidance: ITU‑R BT.2100, BT.2020, BT.709, and IEC 61966-2-4 (xvYCC)

IEC 61966-12-2:2024 is a practical standard for lightweight gamut metadata, bridging content creators and CE displays to improve colour fidelity, interoperability, and HDR-aware reproduction in consumer ecosystems.

Standards Content (Sample)

IEC 61966-12-2 ®
Edition 2.0 2024-10
INTERNATIONAL
STANDARD
Multimedia systems and equipment – Colour measurement and management –
Part 12-2: Simple metadata format for identification of colour gamut

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IEC 61966-12-2 ®
Edition 2.0 2024-10
INTERNATIONAL
STANDARD
Multimedia systems and equipment – Colour measurement and management –

Part 12-2: Simple metadata format for identification of colour gamut

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.180.20; 33.160.40 ISBN 978-2-8322-9821-3

– 2 – IEC 61966-12-2:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Simple description of gamut . 7
5 Relationship with IEC 61966-12-1 . 9
Annex A (informative) Conversion from IEC 61966-12-2 to IEC 61966-12-1 simple
profile . 11
Annex B (informative) Example of simple metadata format and conversion to
IEC 61966-12-1 simple profile . 13
Annex C (informative) Handling HDR content . 18
C.1 General . 18
C.2 Relationship with other HDR related standards . 18
Bibliography . 20

Figure 1 – The colour gamut for display types comprising three primary additive
colours . 9
Figure 2 – IEC 61966-12-1 full and medium profiles . 10
Figure 3 – IEC 61966-12-1 simple profile and IEC 61966-12-2 . 10

Table 1 – Simple metadata format for identification of colour gamut . 8
Table 2 – Differences of IEC 61966-12-1 simple profile and IEC 61966-12-2 . 10
Table B.1 – Colour gamut for IEC 61966-2-5 opRGB . 13
Table B.2 – Encoded simple metadata format . 14
Table B.3 – Conversion result to CIE-XYZ values for five colour vertices . 14
Table B.4 – Example for the header . 15
Table B.5 – Example for the header of description of gamut geometry . 15
Table B.6 – Example of definition of vertices. 15
Table B.7 – Example of encoded colour space coordinates for vertices. 16
Table C.1 – P3D65x1000n0005 in ITU-R H Supl.19 . 18
Table C.2 – Metadata example when distributing content whose colour gamut is DCI-P3 . 19

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 12-2: Simple metadata format for identification of colour gamut

FOREWORD
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IEC 61966-12-2 has been prepared by technical area 2: Colour measurement and management,
of IEC technical committee 100: Audio, video and multimedia systems and equipment. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the number of bits of metadata format has been extended in Clause 4;
b) Annex C has been added for handling HDR content.

– 4 – IEC 61966-12-2:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
100/3847/CDV 100/4109/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of the IEC 61966 series, published under the general title Multimedia systems
and equipment – Colour measurement and management, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
INTRODUCTION
New technologies in capturing and displaying wide-gamut colour images enable a new market
of wide-gamut video colour content creation. Recent video standards for wide gamut colour
space encoding such as ITU-R BT.2100 (HDR), ITU-R BT.2020 (UHDTV) and IEC 61966-2-4
(xvYCC) were developed in order to be able to distribute content with a colour gamut that is
extended with respect to classical colour gamuts such as those defined by standards ITU-R
BT.601 (standard-definition television) and ITU-R BT.709 (high-definition television). With the
increasing popularity of wide gamut and high dynamic range content and displays, the variety
of colour gamuts of displays is expected to increase. This issue can be an obstacle to adoption
of wide-gamut video colour content in professional content creation since the compatibility of
the content to the employed displays, as well as the compatibility among different displays, is
not ensured. The term "display" includes here any video colour reproduction equipment, such
as direct view displays and projectors. Thanks to improvements in technology, the variety of
colour gamuts and colour reproduction capacities of displays are increasing while the colour
gamut and the colour encoding rules of existing colour space encoding standards are fixed.
To address this issue, IEC 61966-12-1 (Metadata for identification of colour gamut (Gamut ID))
specifies a colour gamut metadata scheme for video systems including information for colour
reproduction. This metadata can apply to video content or displays. More specifically,
improvements can be achieved if the wide-gamut colour content is created with the knowledge
of the display colour gamut and if the colour reproduction in the display is done with the
knowledge of the colour gamut of the pictorial content.
IEC 61966-12-1 has the capability to describe arbitrary 3D colour gamuts in a given colour
space and include the full/medium profile for professional use and the simple profile for
consumer use with easier product implementation. This approach is effective, but some
ambiguities can occur in practical use, for example if typical CE devices are able to decode the
simple profile only owing to CPU and software limitations.
In this case, even if a sender device and a receiver device are based on IEC 61966-12-1:
a) the receiver device cannot handle the Gamut ID of incoming content, if the sender device
sends only a full or a medium profile;
b) the sender device should convert a full profile to a simple one for CE devices if the receiver
can receive the simple profile only, but the conversion is not possible for all the cases.
Therefore, a simple Gamut ID profile standard based on this document has been developed to
address this problem.
This second edition extends the number of bits of "back level ratio" in the metadata format to
accommodate the wider dynamic range content and displays.

– 6 – IEC 61966-12-2:2024 © IEC 2024
MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 12-2: Simple metadata format for identification of colour gamut

1 Scope
This part of IEC 61966-12 specifies the colour gamut metadata format for video systems
intended for use in CE (consumer electronics) devices. The metadata specified in this part of
IEC 61966-12 is limited to the gamut description for display types comprising the three primary
additive colours, whose white and black points have the same chromaticity. It is fundamentally
based on the conventional VESA-EDID format.
When associated with content, the simple metadata format defines the gamut for which the
content was created. It can be used by the display for controlled colour reproduction even if the
display’s colour gamut is different from that of the content.
When associated with a display, the simple metadata format defines the display colour gamut.
It can be used during content creation to enable improved colour reproduction.
This document provides the simplest, but unambiguous solution for typical CE devices that are
based on colour gamut information communication.
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.
IEC 60050-845, International Electrotechnical Vocabulary – Part 845: Lighting
IEC 61966-12-1, Multimedia systems and equipment – Colour measurement and management
– Part 12-1: Metadata for identification of colour gamut (Gamut ID)
ISO 15076-1, Image technology colour management – Architecture, profile format and data
structure – Part 1: Based on ICC.2010
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-845 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
content
set of video signals in production, post-production or consumption

3.2
colour gamut
range of colours achievable on a given colour reproduction medium (or present in an image of
that medium) under a given set of viewing conditions
Note 1 to entry: It is a volume in colour space.
3.3
gamut mapping
mapping of the colour-space coordinates of the elements of a source image to colour-space
coordinates of the elements of a reproduction to compensate for differences in the source and
output medium colour gamut capability
4 Simple description of gamut
The three primary additive colours gamut can be specified by four combinations of CIE-xy
chromaticity values of red, green, blue and white. The gamut is assumed to have the
characteristic that combining equal amounts of the three primaries (red, green, blue) produces
the chromaticity of white. These values can be encoded according to the gamut CIE-xy
chromaticity values used in Vesa Enhanced Extended Display Identification Data Standard
(Defines EDID Structure Version 1, Revision 4). The description includes eight values (CIE-xy
chromaticity values for each red, green, blue and white) with 10-bit fixed point form in the range
of 0,0 to 1,0. These display primary and the white
...