Sustainability of Digital Formats: Planning for Library of Congress Collections

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JPEG XS File Format

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name JPEG XS File Format [From ISO/IEC 21122-3 Information technology — JPEG XS low-latency lightweight image coding system — Part 3: Transport and container]
Description

JPEG XS is a file format for storing single images. Per intoPIX, lead developer of the codec, "XS" of the JPEG XS codec stands for "extra small" and "extra speed" to reflect compression efficiency. The JPEG XS file format supports high dynamic range (HDR), high bit depth, and visually lossless quality.

See JPEG XS Encoding for more information on the JPEG XS coding system.

Comments welcome.

Production phase Used most often for middle- and final-state archiving or end-user delivery. Comments welcome.
Relationship to other formats
    Subtype of ISO_BMFF, ISO Base Media File Format
    Contains JPEG_XS, JPEG XS Encoding

Local use Explanation of format description terms

LC experience or existing holdings The Library of Congress does not have any JXS files inventoried in its collections.
LC preference The Library of Congress has not yet expressed any format preference for JPEG XS encoding or JPEG XS file formats in the Recommended Formats Statement for Still Image in its collections.

Sustainability factors Explanation of format description terms

Disclosure Fully disclosed. This is an ISO published standard, specified in the ISO/IEC 21122-3: Information technology — JPEG XS low-latency lightweight image coding system — Part 3: Transport and container.
    Documentation

As of May 2022, this standard is in published status. The ISO/IEC 21122-1 format specification is broken down into four parts. Parts 1 through 3 released updated versions of their specifications in 2022. The 2022 versions of Parts 4 and 5 remain in development, but the 2019 versions remain available.

Part 1 carries the running title, Part 1: Core coding system, which "Defines the JPEG XL codestream and decoder, which can be used for lossy encoding, lossless encoding, and lossless re-compression of existing JPEG images."

Part 2 carries the running title, Part 2: Profiles and buffer models. Part 2, "specifies an extensible box-based file format which adds support for metadata (e.g. Exif and JUMBF) and legacy JPEG bitstream reconstruction data."

Part 3 carries the running title, Part 3: Transport and container. Part 3 defines how to embed the codestream into a more descriptive file format and "contains all definitions are that necessary to transport a codestream."

Part 4 carries the running title: Part 4, Conformance testing, which defines the conformance testing for JPEG XS. A second edition is under development that permits faster decoder implementations.

Part 5 carries the running title: Part 5, Reference software. This outlines the JPEG XS reference software.

Adoption

The JPEG XS Use Cases and Requirements details the applications and real-time implementations of JPEG XS.

  • Medical imaging
  • Mobile device displays

In a 2018 interview, Antonin Descampe, one of the lead engineers and co-founders of intoPIX, stated that, "the purposes of the JPEG XS standard is not to replace the JPEG. It is rather in specific areas that we want to intervene, such as proposing a standard that compresses very slightly without visual loss for existing infrastructure."

Comments welcome.

    Licensing and patents See JPEG XS.
Transparency See JPEG XS.
Self-documentation

ISO/IEC 21122-3 defines metadata information such as: color spaces, mastering display metadata (MDM), as well as EXIF metadata to facilitate transport, editing, and presentation.

External dependencies None.
Technical protection considerations None.

Quality and functionality factors Explanation of format description terms

Still Image
Normal rendering See JPEG XS.
Clarity (high image resolution) See JPEG XS.
Color maintenance See JPEG XS.
Support for vector graphics, including graphic effects and typography See JPEG XS.
Support for multispectral bands See JPEG XS.
Functionality beyond normal rendering See JPEG XS.

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension jxs
 
Internet Media Type image/jxs
See IANA registration. https://www.iana.org/assignments/media-types/image/jxs.
Magic numbers 0x0000 000C 4A58 5320 0D0A 870A
Via IANA, see https://www.iana.org/assignments/media-types/image/jxs. Specified in ISO/IEC 21122-3. Comments welcome.
Wikidata Title ID See note.
Wikidata has no corresponding entry for the JPEG XS file format. See https://www.wikidata.org/wiki/Q60776453 for the Wikidata entry for the JPEG XS encoding.
Pronom PUID See Note.
There is no PRONOM PUID for the JPEG XS codec at this time.

Notes Explanation of format description terms

General  
History See JPEG XS.

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: 07/12/2022