ISO/IEC 23008-12:2017

INTERNATIONAL ISO/IEC
STANDARD 23008-12
First edition
2017-12
Information technology — High
efficiency coding and media delivery
in heterogeneous environments —
Part 12:
Image File Format
Technologies de l'information — Codage à haute efficacité et livraison
des medias dans des environnements hétérogènes —
Partie 12: Format de fichier d'image
Reference number
ISO/IEC 23008-12:2017(E)
©
ISO/IEC 2017

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ISO/IEC 23008-12:2017(E)

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© ISO/IEC 2017, Published in Switzerland
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ISO/IEC 23008-12:2017(E)

Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 5
4 Overview . 5
5 General requirements . 7
5.1 General requirements on files. 7
5.2 General requirements on readers . 7
5.3 Multi-purpose files . 7
5.4 Other boxes . 7
6 Single image and image collection . 7
6.1 General . 7
6.2 Derivation from the ISO base media file format . 8
6.3 Derivation of an output image of an image item . 8
6.4 Roles of images . 9
6.4.1 General. 9
6.4.2 Hidden images . 9
6.4.3 Cover image . 9
6.4.4 Thumbnail images . 9
6.4.5 Auxiliary images . 9
6.4.6 Master images . 9
6.4.7 Pre-derived coded images .10
6.4.8 Multi-layer images .10
6.5 Image properties .10
6.5.1 General.10
6.5.2 Decoder configuration and initialization .11
6.5.3 Image spatial extents .11
6.5.4 Pixel aspect ratio .12
6.5.5 Colour information .12
6.5.6 Pixel information .13
6.5.7 Relative location .13
6.5.8 Image properties for auxiliary images .14
6.5.9 Clean aperture . .15
6.5.10 Image rotation .15
6.5.11 Layer selection .16
6.5.12 Image mirroring .16
6.6 Derived images and derived image items .17
6.6.1 General.17
6.6.2 Derived image types and derived image item types .17
6.7 Image metadata .19
6.8 Relating an untimed item to a timed sequence .20
6.8.1 'eqiv' entity group .20
6.8.2 'eqiv' sample group .20
7 Image sequences .21
7.1 General .21
7.2 Derivation from the ISO base media file format .21
7.2.1 Track Header box .21
7.2.2 Handler type .22
7.2.3 Coding Constraints box .22
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ISO/IEC 23008-12:2017(E)

7.3 Presentation of an image sequence track .23
7.4 Sample groups .23
7.4.1 Direct reference samples list .23
7.5 Other tracks .25
7.5.1 General.25
7.5.2 Thumbnail image sequence track .25
7.5.3 Auxiliary image sequence track .25
8 Metadata support .26
8.1 General .26
8.2 Metadata for image items .26
8.3 Metadata for image sequence tracks.26
8.4 Integrity checks .26
8.4.1 General.26
8.4.2 Syntax .27
8.4.3 Semantics .27
9 Extensions to the ISO base media file format .28
9.1 General .28
9.2 ItemInfoEntry.28
9.3 Item Properties Box .28
9.3.1 Definition .28
9.3.2 Syntax .29
9.3.3 Semantics .29
9.4 Entity grouping .30
9.4.1 General.30
9.4.2 Groups List box . .30
9.4.3 Entity to Group box .30
9.5 Additional track references .31
9.6 Repeating edits .31
9.6.1 Definition .31
9.6.2 Syntax .32
9.6.3 Semantics .32
9.7 Sample-to-item sample grouping.32
9.7.1 Definition .32
9.7.2 Syntax .33
9.7.3 Semantics .33
10 Image File Format brands .33
10.1 General .33
10.2 Image and image collection brands .34
10.2.1 'mif1' structural brand .34
10.3 Image sequence brands .35
10.3.1 'msf1' structural brand .35
Annex A (normative) Storage of externally specified metadata .37
Annex B (normative) HEVC Image File Format .39
Annex C (normative) High efficiency image file MIME type registration.51
Annex D (normative) High efficiency image sequence file MIME type registration .54
Annex E (normative) AVC in the Image File Format .56
Annex F (normative) Advanced coding image MIME type registration .61
Annex G (normative) Advanced coding sequence MIME type registration.63
Annex H (normative) JPEG in the Image File Format .64
Annex I (informative) Guidelines for specifying storage of image coding formats .67
Annex J (informative) Examples of image collections .68
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ISO/IEC 23008-12:2017(E)

Annex K (informative) Guidelines for progressive refinement .70
Bibliography .72
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ISO/IEC 23008-12:2017(E)

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. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
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 ISO documents 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 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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 29, Coding of
audio, picture, multimedia and hypermedia information.
A list of all parts in the ISO/IEC 23008 series can be found on the ISO website.
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ISO/IEC 23008-12:2017(E)

Introduction
The Image File Format is designed to enable the interchange of images and image sequences, as well as
their associated metadata. It forms part of a family of specifications that are box-structured and is built
using tools defined in the ISO base media file format. This document specifies both structural brands
that can be used with any codec and brands specific to High Efficiency Video Coding (HEVC). The file
format specified in this document is referred to as the High Efficiency Image File Format (HEIF). When
the requirements of the HEVC-specific brands are obeyed, the file format can be referred to as the HEVC
Image File Format.
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INTERNATIONAL STANDARD ISO/IEC 23008-12:2017(E)
Information technology — High efficiency coding and
media delivery in heterogeneous environments —
Part 12:
Image File Format
1 Scope
The formats defined in this document enable the interchange, editing, and display of images, as well as
the carriage of metadata associated with those images.
The Image File Format builds on tools defined in ISO/IEC 14496-12 to define an interoperable storage
format for a single image, a collection of images, and sequences of images.
This document specifies brands for the storage of images and image sequences conforming to High
Efficiency Video Coding (HEVC).
NOTE The storage of HEVC video sequences is out of scope and is handled by ISO/IEC 14496-15.
This format defines normative structures used to contain metadata, how to link that metadata to the
images, and defines how metadata of certain forms is carried.
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/IEC 10918-1:1994, Information technology Digital compression and coding of continuous-tone still
images — Part 1: Requirements and guidelines
ISO/IEC 14496-10, Information technology — Coding of audio-visual objects — Part 10: Advanced
Video Coding
ISO/IEC 14496-12:2015, Information technology — Coding of audio-visual objects — Part 12: ISO base
media file format
ISO/IEC 14496-15, Information technology — Coding of audio-visual objects — Part 15: Carriage of
network abstraction layer (NAL) unit structured video in the ISO base media file format
ISO/IEC 23008-2:2015, Information technology — High efficiency coding and media delivery in
heterogeneous environments — Part 2: High efficiency video coding
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 14496-12 and the
following apply.
For the purposes of Annex B and Annex E, the terms, definitions, and abbreviated terms specified in
ISO/IEC 14496-15 apply.
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ISO/IEC 23008-12:2017(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
alternate group
group of entities (3.1.10) that are alternatives to each other and out of which only one should be selected
for processing
3.1.2
associated image item
image item (3.1.17) that is associated with the item property (3.1.26) through the ItemPropertiesBox
3.1.3
auxiliary image
image (3.1.15) that may not be intended to be displayed but provides supplemental information, such as
transparency data, complementing a respective master image (3.1.27)
3.1.4
coded image
coded representation of an image (3.1.15)
3.1.5
coded image item
item (3.1.25) whose data is a coded image (3.1.4)
3.1.6
crop-rotate-mirror derived image item
derived image item (3.1.8) of type 'iden' that is not associated with any other types of essential item
properties (3.1.11) than 'irot', 'clap', and 'imir'
3.1.7
derived image
representation of an image (3.1.15) as an operation (3.1.31) on other images
3.1.8
derived image item
item (3.1.25) whose data is a derived image (3.1.7)
3.1.9
descriptive item property
item property (3.1.26) that describes rather than transforms the associated item
3.1.10
entity
item or track
3.1.11
essential item property
item property (3.1.26) that readers are required to process
3.1.12
HEVC image item
image item (3.1.17) of type 'hvc1' or 'lhv1'
3.1.13
hidden image
image (3.1.15) that is not intended to be displayed
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ISO/IEC 23008-12:2017(E)

3.1.14
hidden sample
sample that is not intended to be displayed
3.1.15
image
one or more arrays of pixels of different colour components described by an image item (3.1.17) or a sample
3.1.16
image collection
set of images (3.1.15) stored as items (3.1.25) of a single file according to this specification
3.1.17
image item
coded image item (3.1.5) or derived image item (3.1.8)
3.1.18
image property
item property (3.1.26) for an image item (3.1.17)
3.1.19
image sequence
sequence of coded images (3.1.4) which may be associated with advisory timing and in which images
may use inter prediction (3.1.22)
3.1.20
image sequence track
track that contains an image sequence (3.1.19)
3.1.21
input image
image (3.1.15) that is used as an input for the operation (3.1.31) of the derived image item (3.1.8)
3.1.22
inter prediction
prediction derived in a manner that is dependent on data elements (e.g. sample values or motion
vectors) of images (3.1.15) other than the current image
3.1.23
intra coding
coding of an image (3.1.15) that may use intra prediction (3.1.24) and does not use inter prediction
(3.1.22)
3.1.24
intra prediction
prediction derived from only data elements (e.g. sample values) of the same decoded image
3.1.25
item
data that does not require timed processing, as opposed to sample data, and is described by the boxes
contained in a MetaBox
3.1.26
item property
descriptive or transformative information about an item (3.1.25) as stored in the item properties array
3.1.27
master image
image that is stored as an item (3.1.25) and is not an auxiliary image (3.1.3) or a thumbnail image (3.1.37)
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