# google/butteraugli

butteraugli estimates the psychovisual difference between two images

Repository: https://github.com/google/butteraugli
Canonical: https://ross.abutalabs.com/products/butteraugli
Language: C++
License: Apache-2.0
License Family: permissive
Archived: true
Last push: 2022-09-09T07:22:58+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3863, "days_push": 1454, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2001, forks 141 (observed 2026-08-28T04:06:04.377452+00:00)

## What it is
Butteraugli is a C++ library and command-line tool that estimates the psychovisual difference between two images, producing both a scalar score and a spatial heatmap of differences. It is designed to be reliable for barely noticeable differences, making it useful as a quality metric for lossy image and video compression.

## Use cases
- measure perceived difference between two images
- compare quality of two image compression methods
- tune jpeg quality settings based on perceptual similarity
- generate a heatmap of visual differences between images
- evaluate lossy image or video compression quality
- compare png and jpg images psychovisually

## When to choose
- you need a perceptual image quality metric tuned for barely noticeable differences
- you are building or evaluating lossy image/video codecs
- you want a scalar score plus a spatial difference map
- you need a C++ library you can integrate into a compression pipeline

## When to avoid
- you need to compare images with major deformations rather than subtle differences
- you need bindings for languages other than C++
- you want a maintained tool with frequent releases
- you need a simple all-purpose image diff without psychovisual modeling

## Facets
- artifact type: library
- maturity: maintenance
- function: image-processing, benchmarking, developer-tools
- domain: image-processing, graphics, performance
- platform: cpp, cross-platform, cli
- tags: psychovisual-metric, image-quality, perceptual-diff, compression-quality, heatmap

## Member repositories
- google/butteraugli (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:04.377452+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:02:06.227176+00:00, confidence not recorded.
  - readme: https://github.com/google/butteraugli (fetched 2026-08-28T04:06:04.377452+00:00, sha 7fa2382cee62)
- Data as of 2026-08-30T08:39:29.467469+00:00.