Friday March 17, 2017

Google Increases JPEG Compression by 35% Without Loss in Image Quality

Google has developed a new compression algorithm for JPEG images that shrinks them 35% smaller than today's methods without image loss. According to the Google blog announcement post, "Guetzli is a JPEG encoder for digital images and web graphics that can enable faster online experiences by producing smaller JPEG files while still maintaining compatibility with existing browsers, image processing applications and the JPEG standard." Guetzli focuses on compression at the quantization stage as that is where more visual degeneration of the image occurs.

To accomplish this, Guetzli is using psychovisual research based on HVS or the human visual system model. HVS is the study of what humans perceive to be suitably, visually similar. This research worked for the advent of color television as a way to save on bandwidth, and now jpeg compression. 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. Pretty impressive!

News Image

It is our hope that webmasters and graphic designers will find Guetzli useful and apply it to their photographic content, making users’ experience smoother on image-heavy websites in addition to reducing load times and bandwidth costs for mobile users. Last, we hope that the new explicitly psychovisual approach in Guetzli will inspire further image and video compression research.