artefact

Reconstructs lost JPEG detail for smoother, more pleasing images — Rust rewrite of jpeg2png, ~3× faster, runs natively via CLI or directly in the browser via WASM.

JPEG compression discards data and regular decoders "fill in" the gaps with noisy guesses that create visible artifacts. Instead of patching holes, artefact re-optimizes the DCT coefficients with a regularized solver to produce smoother gradients with less staircasing.

Demos

Photo by Aleksandar Pasaric

Photo by Toa Heftiba Şinca

Features

Rust core — port of jpeg2png from C++ to Rust (backend/artefact-core)
~3× faster — rayon parallelism + optional SIMD (wide / std::simd, simd_adaptive for x8/x16/x32/x64 dispatch)
WASM-ready — backend/artefact-wasm via wasm-pack, runs 100% client-side at artefact.delnegend.com (no upload)
CLI + Web — same solver for native binary (artefact-cli) and browser (frontend Nuxt + vite-plugin-wasm)
Flexible I/O — input .jpg/.jpeg, output png/webp/tiff/bmp/gif (auto by extension)
Tunable solver — per-channel weight / pweight / iterations, separate_components for YCbCr

Quick start

Installation

Pre-built CLI (recommended):

# download from Releases (output: artefact-cli, .exe on Windows)
# https://github.com/Delnegend/artefact/releases/latest

Build from source:

git clone https://github.com/Delnegend/artefact.git
cd artefact

# native CLI (release, uses mold + clang if in devcontainer)
cargo build --bin artefact-cli --release
# or: just build

# cross-compiled (linux x64 musl, windows x64, macOS arm64)
# built on GitHub Actions via .github/workflows/release.yml — see Development

Web (no install):

Open artefact.delnegend.com — everything runs in your browser.

Usage

1. The performance way — CLI:

# basic: input.jpg -> input.png (same dir)
artefact-cli input.jpg

# choose output and format
artefact-cli input.jpg -o output.webp --format webp -y

# tune solver (single value for all channels, or Y,Cb,Cr)
artefact-cli input.jpg --weight 0.3 --pweight 0.001 --iterations 50
artefact-cli input.jpg --weight 0.3,0.2,0.3 --iterations 50,30,50

# benchmark without writing file
artefact-cli input.jpg --benchmark

# help
artefact-cli --help

2. The convenience way — browser:

Go to artefact.delnegend.com
Drop a JPEG
Compare input/output with the slider and download PNG

WASM is slower than native but stays fully client-side.

Development

Prerequisites

Recommended: devcontainer — no host toolchain needed:

# VS Code: Command Palette → Reopen in Container
# CLI:
devcontainer up --workspace-folder .

Toolchain is baked into the image (Rust nightly + rust-analyzer, mold 2.40.4, cargo-binstall/flamegraph/wasm-pack, just, fzf, bun) for cache and for editors that skip postCreateCommand (e.g. Zed). postinstall.sh only runs bun i in frontend.

Without devcontainer:

Rust via rustup (nightly, minimal profile)
just, bun, wasm-pack
zip/tar only if manually archiving — releases (linux x64 musl, windows x64, macOS arm64) are built on GitHub Actions via .github/workflows/release.yml. ffmpeg only for sample image generation (not in devcontainer by default).

See docs/development.md for full prerequisites and sample-image helpers.

Repository overview

.
├── backend/
│   ├── artefact-core/    # core solver — scalar / simd_8 / simd_adaptive pipelines
│   ├── artefact-cli/     # native binary (clap)
│   ├── artefact-wasm/    # wasm-pack cdylib for frontend
│   └── zune-jpeg/        # fork of zune-jpeg — exposes DCT coeffs + fixes
├── frontend/             # Nuxt 4 + Vue + Vite + Tailwind — src/utils/artefact-wasm is generated
├── assets/               # demo images (01.png-04.png)
└── docs/development.md   # directory structure, SIMD flags, cross-compile, WASM/web builds

Workspace versions are centralized in [workspace.dependencies] at the root Cargo.toml:5 — bump once, inherited via workspace = true in each crate.

Build

# frontend dev (hot reload)
just dev
# or: cd frontend && bun x nuxt dev --no-fork

# WASM lib (generates frontend/src/utils/artefact-wasm)
just build wasm
# or: wasm-pack build backend/artefact-wasm --target web --out-dir frontend/src/utils/artefact-wasm

# web (static generate for GitHub Pages)
just build web
# or: cd frontend && bun x nuxt generate

# native CLI (release, LTO)
just build            # -> target/release/artefact-cli
# or: cargo build --bin artefact-cli --release

# cross-compiled releases (linux x64 musl, windows x64, macOS arm64)
# built on GitHub Actions via .github/workflows/release.yml
# trigger: workflow_dispatch (release_version + create_release) or merged PR

SIMD / solver flags are toggled in backend/artefact-core/Cargo.toml features (simd, simd_std, simd_adaptive, native, moz) and enabled in dependent crates — see docs/development.md#simd-implementation.

Checks

just check          # cargo fmt + cargo clippy + oxlint + prettier (all)
just check rust     # Rust only
just check js       # frontend only (oxlint + prettier)

Sample images with chroma subsampling:

just encode              # assets/sample.png -> assets/sample.{j444,j422,j420,444,422,420}.input.jpg (needs ffmpeg)
just decode 420          # -> assets/sample.420.decoded.png via artefact-cli
just flame 420           # flamegraph for profiling

Architecture

graph TD
    Z[zune-jpeg<br/>fork - DCT coeffs] --> L[artefact-core<br/>solver<br/>scalar / simd_8 / simd_adaptive<br/>rayon]
    L --> C[artefact-cli<br/>clap - png/webp/tiff/bmp/gif]
    L --> W[artefact-wasm<br/>wasm-bindgen<br/>cdylib]
    W --> F[frontend<br/>Nuxt 4 / Vue / Vite<br/>vite-plugin-wasm + PWA<br/>artefact.delnegend.com]
    F -. upload .-> W

artefact-core is feature-gated: default scalar, simd enables wide, simd_adaptive adds runtime dispatch, native uses LLVM mul_add (-Ctarget-cpu=native), moz swaps zune-jpeg for mozjpeg-sys.

CLI reference

Flag	Short	Default	Description
`<input>`	—	—	Input JPEG file
`--output <path>`	`-o`	`<input>.png`	Output file (extension infers format when `--format auto`)
`--format <fmt>`	`-f`	`auto`	`auto` or `png`/`webp`/`tiff`/`bmp`/`gif`
`--weight <f32>`	`-w`	`0.3`	2nd-order weight — higher = smoother, less staircasing. Single or `Y,Cb,Cr`
`--pweight <f32>`	`-p`	`0.001`	Fidelity weight — higher = closer to source JPEG
`--iterations <n>`	`-i`	`50`	Solver iterations — higher = better but slower. Single or `Y,Cb,Cr`
`--spearate-components`	`-s`	`false`	Optimize Y/Cb/Cr separately instead of jointly
`--benchmark`	`-b`	`false`	Run solver but don't write output
`--overwrite`	`-y`	`false`	Overwrite existing output

Defined in backend/artefact-cli/main.rs:6 and backend/artefact-core/lib.rs:50.

Contributing

PRs welcome. For large changes, please open an issue first.

git clone https://github.com/Delnegend/artefact.git
# devcontainer recommended, else install prerequisites above
just check   # must pass before PR

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion shall be dual-licensed as below without additional terms (per Apache-2.0 §5).

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-Apache or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Acknowledgements

Based on jpeg2png by Victor van der Elst. Thanks to zune-jpeg / zune-image and the Rust / WASM / Nuxt communities.

Name		Name	Last commit message	Last commit date
.devcontainer		.devcontainer
.github		.github
assets		assets
backend		backend
docs		docs
frontend		frontend
.gitignore		.gitignore
.prettierrc		.prettierrc
CNAME		CNAME
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE-Apache		LICENSE-Apache
LICENSE-MIT		LICENSE-MIT
README.md		README.md
justfile		justfile

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