Foreword

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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.

This second edition cancels and replaces the first edition ( ISO/IEC 23000-22:2019 ), which has been technically revised. It also incorporates the Amendments ISO/IEC 23000-22:2019/Amd 1:2021 and ISO/IEC 23000-22:2019/Amd 2:2021 .

The main changes are as follows:

additional adjustments on chroma subsampling.

A list of all parts in the ISO/IEC 23000 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.

Introduction

This document specifies a multimedia application format, the Multi-Image Application Format (MIAF), that enables precise interoperability points for creation, reading, parsing, and decoding of images embedded in the High Efficiency Image File (HEIF) format. This document (MIAF) fully conforms to the HEIF format and only defines additional constraints to ensure higher interoperability.

ISO/IEC 23008-12 (HEIF) defines a file format for the inclusion of one or more images, possibly with one or more sequences of images, with associated metadata and their relationship to each other. While the HEIF specification defines the file format and general requirements for the included coding formats, it does not define specific interoperability points by which capturing devices, editing applications, storage systems, cloud and delivery networks, and playback devices and applications can interoperate with each other.

This document, by defining specific constraints on the HEIF format, limiting the supported encoding types to a set of specific profiles and levels, requiring specific metadata formats, and defining a set of brands for signalling such constraints, defines precise interoperability points which enable the industry to deploy particular uses of the HEIF specification to improve interoperability.

This document defines the normative requirements for MIAF files as well as for MIAF readers and renderers.

1 Scope

This document specifies the Multi-Image Application Format (MIAF), which contains coded images, groups and sequences of images along with their metadata and the information about their relations to each other, all embedded in the High Efficiency Image File (HEIF) format.

This document builds on ISO/IEC 23008-12 (HEIF) and specifies the following:

a set of additional constraints on ISO/IEC 23008-12 (HEIF), to simplify its file format options;
specific alpha plane formats;
a set of specific profiles and levels for the supported coding formats;
a set of specific metadata formats;
a set of brands, including application brands indicating conformance with specific profiles;
a set of rules for extending MIAF format to support additional coding formats, profiles, levels and metadata.

This document also defines the normative behaviour for a MIAF reader and MIAF renderer.

This document (MIAF) is intentionally written to be extensible, and to allow for forward compatibility. The format is also permissive of the presence of other data, such as coding formats, metadata, and derived images.

2 Normative references

3 Terms and definitions

4 Abbreviated terms

5 Document organization and conventions

6 MIAF concepts and processing of MIAF files

6.1 General

6.2 MIAF data object model

6.3 MIAF image items

6.4 MIAF thumbnail image items

6.5 MIAF auxiliary image item

6.6 MIAF reader processing model

6.7 MIAF renderer processing model

7 MIAF file general requirements

7.1 General

7.2 Box-level requirements

7.3 Item level requirements on image items

7.4 Track-level requirements on image sequences and video

7.5 Association of image items and tracks

7.6 Metadata

8 Shared conditions and requirements

8.1 General

8.2 Self-containment

8.3 Single-layer

8.4 Grid-limit

8.5 Single-track

8.6 Edit-lists

8.7 Matched-duration

8.8 HDR signalling

9 Profile-independent image item and sequence coding

10 Brands and file extensions

10.1 General

10.2 Progressive application brand

10.3 Animation application brand

10.4 Burst capture application brand

10.5 Fragmented alpha video brand

10.6 Common media fragmented brand

Bibliography

ISO/IEC 23000-22:2025

Information technology. Multimedia application format (MPEG-A) - Multi-image application format (MIAF)

Current, Under Review

Published:

11 Feb 2025