Compressed images may not look amazing, but they provide faster load times for websites. Now, Google hopes to push image compression into the future with “Jpegli,” an open-source coding library that provides a 35% compression ratio improvement over old-school JPEG encoding techniques.
Jpegli is a new technique for encoding and decoding traditional JPEGs. The Jpegli coding library is fully compliant with 8-bit JPEG, meaning that a Jpegli-encoded image can be opened in any old browser, photo editor, or photo viewer. To reiterate, this is a JPEG encoding method, not a new file format.
With Jpegli, Google hopes to provide more effective image compression with minimal quality loss. This will lead to faster page load times, higher-quality graphics on websites, and reduced overhead for web-based businesses. Jpegli may also reduce the web’s reliance on WebP, a Google-made image format that has failed to enjoy widespread adoption (although plenty of CDNs use WebP).
Google promises a 35% compression ratio improvement with Jpegli encoding. This is a substantial leap over encoders. The popular MozJPEG encoder, for example, only provides a 20% improvement over the traditional JPEG compression ratio.
At the heart of Jpegli, you’ll find a retooled version of JPEG XL’s adaptive quantization heuristics algorithm. JPEG XL, a next-gen file format that was briefly tested in Chrome before being sidelined due to maintenance concerns, is now about three years old.
There are some new technologies here, too, including an optimized set of quantization matrices that retains image quality through the compression process. Jpegli can also encode at 10+ bits without losing 8-bit interoperability—if an app or browser supports Jpegli decoding, they can see the 10+-bit image. If a different decoding method is used, the image will appear as 8-bit.
Any individual, business, or app can use Jpegli to encode and decode images. It’s open-source and freely available on Github. However, Jpegli adoption among apps, browsers, and CDNs may be slow. And, despite the fact that this is a backward-compatible encoding method (as opposed to a new file format), some developers may choose to avoid Jpegli.
It’s safe to assume that Google-owned services will be the first to truly embrace Jpegli. The exceptional compression ratio offered by Jpegli could greatly reduce the operating costs of a service like Google Photos, all without compromising image quality or usability.
Source: Google
