ISO/IEC 23008-12:2017/Amd 1:2020

INTERNATIONAL ISO/IEC
STANDARD 23008-12
First edition
2017-12
AMENDMENT 1
2020-11
Information technology — High
efficiency coding and media delivery
in heterogeneous environments —
Part 12:
Image File Format
AMENDMENT 1: Support for predictive
image coding, bursts, bracketing and
other improvements
Technologies de l'information — Codage à haute efficacité et livraison
des medias dans des environnements hétérogènes —
Partie 12: Format de fichier d'image
AMENDEMENT 1: Support pour le codage prédictif des images, les
rafales, le bracketing et autres améliorations
Reference number
ISO/IEC 23008-12:2017/Amd.1:2020(E)
©
ISO/IEC 2020
ISO/IEC 23008-12:2017/Amd.1:2020(E)

© ISO/IEC 2020
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 the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2020 – All rights reserved

ISO/IEC 23008-12:2017/Amd.1:2020(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.
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).
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.
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.
A list of all parts in the ISO/IEC 23008 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 iii

ISO/IEC 23008-12:2017/Amd.1:2020(E)
Information technology — High efficiency coding and
media delivery in heterogeneous environments —
Part 12:
Image File Format
AMENDMENT 1: Support for predictive image coding, bursts,
bracketing and other improvements

Clause 3
Add the following terms and definitions at the end of 3.1:
3.1.40
predictively coded image item
image item (3.1.17) that has a decoding dependency to one or more other coded image items (3.1.5)
3.1.41
unique ID
identifier for either an item, an entity group or a track that fulfils the requirements of the 'unif' brand
Note 1 to entry: Requirements on the 'unif' brand are specified in ISO/IEC 14496-12.
3.1.42
visual context
visual rendering surface such as a screen buffer, which may already contain visual material, and onto
which an image (3.1.15) can be rendered

Clause 4, item a)
Replace the text in item a) with the following:
a) the storage of a single coded image or a collection of coded images, possibly with derived images;
coded images are normally independently coded except when the 'pred' brand is signalled. In
such latter case, coded images may be independently coded or may have been coded with inter
prediction;
Clause 4, third paragraph:
Replace the third paragraph with the following:
In general, the single image support is used for simpler cases, particularly when neither timing nor
coding dependency is required. If advisory timing or other tools from the ISO base media file format
available for tracks are needed (e.g. sample grouping), then the second approach is needed.
© ISO/IEC 2020 – All rights reserved 1

ISO/IEC 23008-12:2017/Amd.1:2020(E)

6.4
Add the following new subclause after subclause 6.4.8:
6.4.9  Predictively coded image items
Predictively coded image items have a decoding dependency to one or more other coded image items.
An example for such an image item could be a P frame stored as an image item in a burst entity group
that has IPPP… structure, with the P frames dependent only on the preceding I frames.
Capability to have predictively coded image items has certain benefits especially in content re-editing
and cover image selection:
— Image sequences can be converted to image items with no transcoding.
— Any sample of an image sequence track can be selected as a cover image. The cover image does not
need to be intra-coded.
— Devices that do not have a video or image encoder are capable of updating the cover image of a file
containing an image sequence track.
— Storage efficiency is further achieved by re-using the predictively coded picture rather than re-
encoding it as I frame and storing as an additional image item. Moreover, image quality degradation
is also avoided.
— Re-encoding might not be allowed or preferred by the copyright owner. Predictively coded image
items avoid the need of re-encoding of any image from an image sequence track.
Predictively coded image items are linked to the coded image items they directly and indirectly depend
on by item references of type 'pred'. The list of referenced items in item references of type 'pred'
shall indicate the decoding order. When concatenated, the encoded media data of items with item_ID
equal to to_item_ID for all values of j from 0 to reference_count − 1, inclusive, in increasing order of
j, followed by the item with item_ID equal to from_item_ID shall form a bitstream that conforms to the
decoder configuration item property of the predictively coded image item.
In order to decode the predictively coded image item, there shall be no other decoding dependencies
other than the image items referenced by item references of type 'pred'.
The predictively coded image item shall be associated with exactly one RequiredReferenceTypesProperty
containing one reference type with the value 'pred'.

6.5.1
Add the following paragraphs at the end of the subclause 6.5.1, after the NOTE:
When unique IDs are used, an item_ID value in the ItemPropertyAssociationBox is resolved to an item
identifier whenever the embedding MetaBox contains an item with such identifier, and is resolved to an
entity group identifier otherwise.
Properties may be associated with an entity group, but only when explicitly stated in their specification.
In such case, properties apply to the entity group as a whole, and not individually to each entity within
the group.
2 © ISO/IEC 2020 – All rights reserved

ISO/IEC 23008-12:2017/Amd.1:2020(E)

6.5
Add the following new subclauses after subclause 6.5.12:
6.5.13  Image scaling
6.5.13.1  Definition
'iscl'
Box type:
Property type: Transformative item property
ItemPropertyContainerBox
Container:
Mandatory (per item): No
Quantity (per item): At most one
The image scaling 'iscl' transformative item property scales an input image.
The input image is the output of the previous transformative item property, if any, or the reconstructed
image of the associated image item.
The width and height of the input image (call those input_width and input_height) are resized to a
target width and height, in pixels, respectively equal to ceil( (input_width * target_width_numerator)
/ target_width_denominator) and ceil((input_height * target_height_numerator) / target_height_
denominator), where ceil() is the ceiling function. The scaling of the input image applies to both width
and height separately. The fraction may or may not be in reduced terms.
NOTE 1 Formulas above use a floating-point division, not an integer division.
NOTE 2 When the input image is the reconstructed image of the associated image item, input_
width and input_height, respectively, are equal to image_width and image_height declared in the
ImageSpatialExtentsProperty associated with this image item. Otherwise, input_width and input_height
are equal to the width and height of the output of the previous transformative item property.
6.5.13.2  Syntax
aligned(8) class ImageScaling
extends ItemFullProperty('iscl', version = 0, flags = 0) {
unsigned int (16) target_width_numerator;
unsigned int (16) target_width_denominator;
unsigned int (16) target_height_numerator;
unsigned int (16) target_height_denominator;
}
6.5.13.3  Semantics
target_width_numerator specifies the numerator of the scaling ratio for the resized image in the
horizontal dimension. The value 0 shall not be used.
target_width_denominator specifies the denominator of the scaling ratio for the resized image in the
horizontal dimension. The value 0 shall not be used.
target_height_numerator specifies the numerator of the scaling ratio for the resized image in the
vertical dimension. The value 0 shall not be used.
target_height_denominator specifies the denominator of the scaling ratio for the resized image in the
vertical dimension. The value 0 shall not be used.
© ISO/IEC 2020 – All rights reserved 3

ISO/IEC 23008-12:2017/Amd.1:2020(E)

6.5.14  Content light level
6.5.14.1  Definition
'clli'
Box type:
Property type: Descriptive item property
ItemPropertyContainerBox
Container:
Mandatory (per item): No
Quantity (per item): At most one
The content light level item property provides information about the light level in the content.
6.5.14.2  Syntax
The content light level 'clli' descriptive item property has the same syntax as the ContentLightLevelBox
as defined in ISO/IEC 14496-12.
6.5.14.3  Semantics
The semantics of the syntax elements within the content light level 'clli' item property are the same
as those specified for the syntax elements of ContentLightLevelBox as defined in ISO/IEC 14496-12.
6.5.15  Mastering display colour volume
6.5.15.1  Definition
'mdcv'
Box type:
Property type: Descriptive item property
ItemPropertyContainerBox
Container:
Mandatory (per item): No
Quantity (per item): At most one
This property provides information about the colour primaries, white point, and mastering luminance
in the content.
6.5.15.2  Syntax
This property has the same syntax as the MasteringDisplayColourVolumeBox as defined in
ISO/IEC 14496-12.
6.5.15.3  Semantics
The semantics of the syntax elements within this property are the same as those specified for the
syntax elements of MasteringDisplayColourVolumeBox as defined in ISO/IEC 14496-12.
4 © ISO/IEC 2020 – All rights reserved

ISO/IEC 23008-12:2017/Amd.1:2020(E)

6.5.16  Content colour volume
6.5.16.1  Definition
'cclv'
Box type:
Property type: Descriptive item property
ItemPropertyContainerBox
Container:
Mandatory (per item): No
Quantity (per item): At most one
This property describes the colour volume characteristics of the associated pictures.
6.5.16.2  Syntax
This property has the same syntax as the ContentColourVolumeBox as defined in ISO/IEC 14496-12.
6.5.16.3  Semantics
The semantics of the syntax elements within this property are the same as those specified for the
syntax elements of ContentColourVolumeBox as defined in ISO/IEC 14496-12.
6.5.17  Required reference types
6.5.17.1  Definition
'rref'
Box type:
Property type: Descriptive item property
ItemPropertyContainerBox
Container:
Mandatory (per item): Yes, for a predictively coded image item. No, otherwise.
Quantity (per item): At most one
The RequiredReferenceTypesProperty descriptive item property lists the item reference types that a
reader shall understand and process to decode the associated image item. The respective essential
flag shall be equal to 1 in ItemPropertyAssociationBox.
NOTE In the absence of this property, required reference types are not explicitly listed, but can still exist.
6.5.17.2  Syntax
aligned(8) class RequiredReferenceTypesProperty
extends ItemFullProperty('rref', version = 0, flags = 0){
unsigned int(8) reference_type_count;
for (i=0; i< reference_type_count; i++) {
unsigned int(32) reference_type[i];
}
}
6.5.17.3  Semantics
reference_type_count indicates the number of reference types that are required to understand and
process to decode the associated image item.
reference_type[i] indicates a reference type that is required to understand and process to decode the
associated image item.
© ISO/IEC 2020 – All rights reserved 5

ISO/IEC 23008-12:2017/Amd.1:2020(E)

6.5.18  Creation time information
6.5.18.1  Definition
'crtt'
Box type:
Property type: Descriptive item property
ItemPropertyContainerBox
Container:
Mandatory (per associated item_ID): No
Quantity (per associated item_ID): At most one
The CreationTimeProperty documents the creation time of the associated item or group of entities.
6.5.18.2  Syntax
aligned(8) class CreationTimeProperty
extends ItemFullProperty('crtt', version = 0, flags = 0) {
unsigned int(64) creation_time;
}
6.5.18.3  Semantics
creation_time is an inte
...