JPEG XL

File Format
Name	JPEG XL
Ontology	Electronic File Formats Graphics JPEG XL
Extension(s)	.jxl
MIME Type(s)	image/jxl
Extended From	[[JPEG, PIK, FUIF]]
Magic Bytes	FF 0A or 00 00 00 0C 4A 58 4C 20 0D 0A 87 0A
Patent License	Royalty-Free
Released	2021

JPEG XL is a compressed image format and/or file format that is yet another attempt to be the next JPEG. It was first announced around 2017-08. It is expected to be published as ISO/IEC 18181.

JPEG XL is based in part on the FUIF and PIK formats.[1] The standard also supports recompression of JPEG files with bit-exact reconstruction.

Identification

Based on the reference implementation, JPEG XL codestreams start with bytes ff 0a. Codestreams may also be wrapped in an ISOBMFF-based file format (implementation). See format overview.

Specifications

• Committee Draft of JPEG XL (2019-08)
• ISO/IEC 18181

Software

• Open-source reference software
• Online converter to JXL

Sample files

• https://telparia.com/fileFormatSamples/image/jpegXL/

Links

• Overview of JPEG XL
• Next-Generation Image Compression (JPEG XL) Draft Call for Proposals (2017-11)
• Revised Draft Call for Proposals (2018-02)
• Final Call for Proposals (2018-04)
• Gigazine article (2017-08-15)
• Slides from Imagecon 2019 presentation
• Introductory paper (open access)
• Benchmarking JPEG XL image compression
• How JPEG XL Compares to Other Image Codecs (2020-05-26)
• Codestream vs Container discussion