Google Guetzli project – Google’s new encoder reduces JPEG file size by 35%
The Search Engine Giant has developed and open-sourced a new JPEG algorithm called Google Guetzli that reduces file size by about 35 percent—or alternatively, image quality can be significantly improved while keeping file size constant. This is to advance its efforts in getting web pages to load faster while using less data.
Google promises that it can create “high-quality JPEG images with file sizes 35 percent smaller than currently available methods.” In addition to making image files that are smaller, Google Guetzli is also focused on creating images that look better than other compressed images, too.
“The visual quality of JPEG images is directly correlated to its multi-stage compression process: colour space transform, discrete cosine transform, and quantization. Guetzli specifically targets the quantisation stage in which the more visual quality loss is introduced, the smaller the resulting file. Guetzli strikes a balance between minimal loss and file size by employing a search algorithm that tries to overcome the difference between the psychovisual modelling of JPEG’s format, and Guetzli’s psychovisual model, which approximates colour perception and visual masking in a more thorough and detailed way than what is achievable by simpler colour transforms and the discrete cosine transform. However, while Guetzli creates smaller image file sizes, the tradeoff is that these search algorithms take significantly longer to create compressed images than currently available methods,” in a blog post.
Google has made the Guetzli encoder open source, and it’s available on Github for anyone to integrate into their own projects or to use on their own. That’s a big deal because right now, many web-based image programs use the libjpeg encoder because it is free and tends to do a good enough job. If Guetzli does work as well as Google claims, this could potentially be a solid libjpeg replacement for web developers, designers or photographers. It will also be good for regular web users because photos and images will take up less space. More details about Guetzli are available a At this link.