Users prefer Guetzli JPEG over same-sized libjpeg

TL;DR

This study shows that Guetzli JPEG images are preferred over libjpeg images of the same size by human raters, indicating Guetzli's high perceptual quality guided by the Butteraugli metric.

Contribution

The paper introduces Guetzli, a new JPEG encoder that produces images preferred by humans, and demonstrates its effectiveness through human preference studies.

Findings

75% of human raters preferred Guetzli images over libjpeg

Guetzli's quality correlates well with human perception via Butteraugli

Source images and ratings are publicly available for further research

Abstract

We report on pairwise comparisons by human raters of JPEG images from libjpeg and our new Guetzli encoder. Although both files are size-matched, 75% of ratings are in favor of Guetzli. This implies the Butteraugli psychovisual image similarity metric which guides Guetzli is reasonably close to human perception at high quality levels. We provide access to the raw ratings and source images for further analysis and study.