Google Has a New Algorithm That Shrinks JPEGs by 35%
Mar 18 2017
Images pushed through the Guetzli encoder are still available in a regular JPEG format, making them compatible with just about every application and browser now on the market. More details at the link below.
Speed is everything on the internet, and as a general rule of thumb: the smaller the file, the faster it'll load. You can see an example of that in the image above, with the original uncompressed image on the left, the same one with the libjpeg encoder in the center, and one that used Guetzli on the right.
The benefit of using Guetzil, aside from the reduction in image size and barely-noticeable changes in image quality, is that the files it turns out remain compatible with existing browsers, image processing programs and the JPEG standard itself.
Google has developed a new compression algorithm for JPEG images that shrinks them 35% smaller than today's methods without image loss.
For Google's Guetzli speed boost, researchers developed a test called Butteraugli created to model human vision.
JPEG compression has several steps, including color space transformation, discrete cosine transformation, and quantization. Google said the breakthrough is the result of an algorithm that balances quality reductions and file size by searching for differences between JPEG and Guetzli representations of image data. Another upside is that the transition to using Guetzli will happen quietly in the background without any disruption to that next image search you perform looking for cute cats. Therefore any compression technique needs to downsample in a manner which leads to the highest perceptual image quality possible, since there is no "way back". Right, Guetzli compression. Credit: Google. By employing a new search algorithm Google was able to address colour perception and visual masking better than the simpler colour transforms employed in current JPEG algorithms. And although Google compared Guetzli to mozjpeg and another JPEG encoder called libjpeg, there are other options, too. This modelling takes longer to process than conventional methods, but in studies 75% of people preferred the Guetzli method over libjpeg even when libjpeg was allowed to use a larger file size.
However, it's worth noting that Guetzli is slower than other options out there.