Recently, Gmail increased the size of attachments its users could receive, and now Google has created an encoder that can shrink the size of JPEGs by 35%. The encoder basically compresses images at a higher level of quality and reduces the amount of time it takes to open them. The new JPEG encoder is called Guetzli, and the company has made it open source and available in the Github repository so anyone can use it.
Google invents new JPEG encoder
According to Ars Technica, the encoder technically works by improving the quality of the JPEG images while keeping the size of the file constant. The website notes that one big distinction is that unlike some other image compression techniques like WebP and WebM, these new JPEGs are compatible with the current JPEG standard and also current devices, browsers and photo editing apps.
Although there are several different ways to adjust the size and quality of a JPEG, Google’s Guetzli (German for “cookie”) is all about the “quantization stage of compression.” This is the process that transforms a lot of the hard-to-compress “disordered data” into easy-to-compress “ordered data.” The problem with standard JPEG encoding is that it usually decreases the quality of the images.
Google uses “psychovisual model”
Google Research said that Guetzli uses Butteraugli, a new “psychovisual model,” to improve the selection process of which bits are thrown out during the compression process. This basically means that the process is based on the way humans see objects, so the encoder uses the way people see to decide which areas of the JPEG can be reduced, thus compressing it in such a way that the quality is improved.
Google said that Guetzli takes much longer to compress images than traditional techniques used to encode JPEG files, according to The Verge. However, other than improved quality, the other result of using this encoder is that files take less time to open. As a result, the company feels that it’s worth the extra time to encode the file.