ISO IEC 18181-2-2024 PDF

Full title and description

Information technology — JPEG XL image coding system — Part 2: File format. Specifies the transport and container formats for JPEG XL codestreams (as defined in ISO/IEC 18181-1), and defines how metadata and extensions (for example EXIF, XMP, ICC profiles and other ancillary information) are carried in a JPEG XL file container.

Abstract

This part of ISO/IEC 18181 defines the file and transport/container format for JPEG XL codestreams. It describes the structure of a JPEG XL file, mechanisms for embedding metadata and extensions, and rules for carriage of codestreams and ancillary data so that implementations can reliably read, write and exchange JPEG XL files.

General information

• Status: Published
• Publication date: June 2024 (Edition 2)
• Publisher: ISO (joint ISO/IEC standard; developed by ISO/IEC JTC 1/SC 29)
• ICS / categories: 35.040.30 (Coding of graphical and photographic information)
• Edition / version: Edition 2 (2024)
• Number of pages: 17

Scope

The standard specifies the container and transport formats used to encapsulate JPEG XL codestreams. It sets out how to identify JPEG XL files, how codestreams and metadata are packaged, and how extensions are signalled so that decoders and other tools can interpret ancillary data (such as EXIF, XMP, ICC profiles) alongside image codestreams. It is intended to complement ISO/IEC 18181-1 (the codestream definition) and to enable interoperable file exchange and transport of JPEG XL images.

Key topics and requirements

• File identification and basic file structure for JPEG XL files.
• Container/transport format rules for embedding JPEG XL codestreams.
• Mechanisms for carrying metadata (EXIF, XMP, ICC profiles and other ancillary data).
• Extension points and rules for optional features and future compatibility.
• Requirements for correct encapsulation so decoders can locate and interpret codestreams and metadata.
• Relationship and referencing to ISO/IEC 18181-1 (codestream specification).

Typical use and users

Implementers of image codecs and image file libraries (for example developers of image-processing libraries, browser and application vendors), camera and device manufacturers, content-delivery and storage systems, digital archiving professionals, and test/conformance laboratories use this standard when adding JPEG XL container/file support or ensuring interoperable exchange of JPEG XL images.

Related standards

ISO/IEC 18181-1 (JPEG XL codestream specification) — defines the codestream itself; ISO/IEC 18181-3 (conformance testing) — defines conformance tests for the series. The Part 2 file-format specification is intended to be used together with Part 1 and with conformance and implementation guidance in other parts of the ISO/IEC 18181 series.

Keywords

JPEG XL, image coding, codestream, file format, container, metadata, EXIF, XMP, ICC profile, transport format, ISO/IEC 18181

FAQ

Q: What is this standard?

A: ISO/IEC 18181-2:2024 is the Part 2 file-format specification of the JPEG XL image coding system. It defines how JPEG XL codestreams are packaged into files and how associated metadata and extensions are carried.

Q: What does it cover?

A: It covers the container and transport formats for JPEG XL codestreams, file identification, metadata embedding (EXIF, XMP, ICC and similar), extension mechanisms and the rules needed for interoperable reading and writing of JPEG XL files.

Q: Who typically uses it?

A: Software developers implementing JPEG XL support (libraries, browsers, image editors), device and camera manufacturers, CDN and storage providers, digital preservation specialists, and test/conformance labs.

Q: Is it current or superseded?

A: Edition 2 of ISO/IEC 18181-2 was published in June 2024 and is the current published edition. It supersedes the 2021 edition; the ISO lifecycle indicates the series is subject to ongoing revision and further drafts (proof/FDIS stages) have been prepared to maintain or update the text.

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO/IEC 18181 series for the JPEG XL image coding system. Part 1 defines the codestream, Part 2 defines the file/container format, and other parts (for example conformance testing) cover additional aspects of the standard family.

Q: What are the key keywords?

A: JPEG XL, file format, codestream, metadata, EXIF, XMP, ICC, transport, container.