Journey to JPEG XL: open-source experiments shaped the future of image coding

Google researchers describe a decade-long journey of open-source experiments that led to the development of JPEG XL, a modern image compression standard. Key innovations included WebP Lossless, the Butteraugli psychovisual metric, and projects like Guetzli and Brunsli that pushed the limits of legacy JPEG compression before converging into the PIK proposal. JPEG XL now offers significantly better compression efficiency and support for modern display technologies like HDR and Wide Color Gamut, addressing limitations of the JPEG standard that had remained largely unchanged since 1992.