The JPEG XL Image Coding System: History, Features, Coding Tools, Design Rationale, and Future

2025-06-06

AI Summary

To address the low compression efficiency and functional fragmentation of legacy image formats (e.g., JPEG, PNG, GIF), this paper introduces JPEG XL—a unified, general-purpose next-generation image coding standard. JPEG XL employs a single codec architecture to jointly support lossy and lossless compression, progressive rendering, animation, and responsive imaging—resolving longstanding format silos. Key technical innovations include: (1) the first practical lossless transcoding of JPEG images; (2) adaptive quantization; (3) modular entropy coding; (4) neural-network-enhanced preprocessing; and (5) reversible color transformations—all designed to maximize compression performance while maintaining low decoding complexity. Experimental results demonstrate that JPEG XL achieves, on average, 60% bit-rate reduction over JPEG at equivalent subjective quality, and outperforms PNG in lossless compression efficiency. JPEG XL has been formally standardized as ISO/IEC 18181.

Technology Category

• Computer Vision: Image and Video Retrieval
• Machine Learning: Learning on the Edge & Model Compression
• Data Mining & Knowledge Management: Data Compression

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

JPEG XL is a new image coding system offering state-of-the-art compression performance, lossless JPEG recompression, and advanced features. It aims to replace JPEG, PNG, GIF, and other formats with a single universal codec. This article provides an overview of JPEG XL, including its history, design rationale, coding tools, and future potential. It can be used as a companion document to the standard (ISO/IEC 18181), or as a standalone article to better understand JPEG XL, either at a high level or in considerable technical detail.

Problem

• JPEG XL aims to replace multiple image formats with one universal codec.
• It offers advanced compression and lossless JPEG recompression capabilities.
• The paper explains JPEG XL's design, tools, and future potential.

Innovation

• State-of-the-art image compression performance
• Lossless JPEG recompression capability
• Universal codec replacing multiple formats