zencodecs

Unified image codec dispatch for Rust. Thin layer over format-specific encoders and decoders: zenjpeg, zenwebp, zengif, zenavif, zenpng, zenjxl, and heic-decoder (Imazen fork).

Usage

use zencodecs::{ImageFormat, DecodeRequest, EncodeRequest, PixelBufferConvertExt};
use zencodecs::pixel::{ImgVec, Rgba};

// Detect format from magic bytes and decode
let data: &[u8] = todo!(); // your image bytes
let decoded = DecodeRequest::new(data).decode()?;
println!("{}x{}", decoded.width(), decoded.height());

// Convert to RGBA8 for processing
let rgba = decoded.into_buffer().to_rgba8();

// Encode as WebP from typed pixel data
let pixels = ImgVec::new(vec![Rgba { r: 0u8, g: 0, b: 0, a: 255 }; 100*100], 100, 100);
let webp = EncodeRequest::new(ImageFormat::WebP)
    .with_quality(85.0)
    .encode_rgba8(pixels.as_ref())?;
println!("Encoded {} bytes", webp.len());
# Ok::<(), zencodecs::CodecError>(())

Typed Encode Methods

Each encode method takes a typed ImgRef<P>:

req.encode_rgb8(img)       // ImgRef<Rgb<u8>>
req.encode_rgba8(img)      // ImgRef<Rgba<u8>>
req.encode_bgra8(img)      // ImgRef<Bgra<u8>>
req.encode_bgrx8(img)      // ImgRef<Bgra<u8>> — alpha ignored
req.encode_gray8(img)      // ImgRef<Gray<u8>>
req.encode_rgb_f32(img)    // ImgRef<Rgb<f32>> — linear light
req.encode_rgba_f32(img)   // ImgRef<Rgba<f32>> — linear light
req.encode_gray_f32(img)   // ImgRef<Gray<f32>> — linear light

The dispatch layer handles pixel format conversion to whatever the codec needs natively.

Probing

use zencodecs::from_bytes;

let info = from_bytes(data)?;
println!("{:?} {}x{}", info.format, info.width, info.height);
# Ok::<(), zencodecs::CodecError>(())

Runtime Codec Control

use zencodecs::{CodecRegistry, ImageFormat, DecodeRequest};

let registry = CodecRegistry::none()
    .with_decode(ImageFormat::Jpeg, true)
    .with_decode(ImageFormat::WebP, true);

let decoded = DecodeRequest::new(data)
    .with_registry(&registry)
    .decode()?;
# Ok::<(), zencodecs::CodecError>(())

Format-Specific Config

use zencodecs::{EncodeRequest, ImageFormat};
use zencodecs::config::CodecConfig;

let config = CodecConfig::default();
// .with_jpeg_encoder(...)
// .with_avif_speed(...)
// etc.

let request = EncodeRequest::new(ImageFormat::Jpeg)
    .with_codec_config(&config)
    .with_quality(92.0);

Cooperative Cancellation and Limits

use zencodecs::{DecodeRequest, Limits};

let limits = Limits {
    max_width: Some(4096),
    max_height: Some(4096),
    max_pixels: Some(16_000_000),
    max_memory_bytes: Some(256_000_000),
    ..Default::default()
};

let decoded = DecodeRequest::new(data)
    .with_limits(&limits)
    .decode()?;
# Ok::<(), zencodecs::CodecError>(())

Stop tokens (enough::Stop) are forwarded to codecs that support cooperative cancellation.

Features

Every codec is feature-gated. Enable only what you need:

[dependencies]
zencodecs = { version = "0.1", features = ["jpeg", "webp", "png"] }

Feature	Codec	Decode	Encode	Notes
jpeg	zenjpeg	Yes	Yes
jpeg-ultrahdr	zenjpeg	Yes	Yes	UltraHDR gain map support
webp	zenwebp	Yes	Yes
gif	zengif	Yes	Yes
gif-zenquant	zengif + zenquant	Yes	Yes	Palette quantization via zenquant
gif-quantizr	zengif + quantizr	Yes	Yes	Palette quantization via quantizr
gif-imagequant	zengif + imagequant	Yes	Yes	Palette quantization via imagequant
png	zenpng	Yes	Yes
png-zenquant	zenpng + zenquant	Yes	Yes	Palette quantization
avif-decode	zenavif	Yes	No
avif-encode	zenavif	No	Yes
jxl-decode	zenjxl	Yes	No
jxl-encode	zenjxl	No	Yes
heic-decode	heic-decoder (Imazen fork)	Yes	No
bitmaps	zenbitmaps	Yes	Yes	PNM/PAM/PFM, BMP, Farbfeld
bitmaps-bmp	zenbitmaps	Yes	Yes	BMP only
tiff	zentiff	Yes	Yes
raw-decode	zenraw	Yes	No	RAW/DNG via rawloader (LGPL)
raw-decode-exif	zenraw	Yes	No	EXIF metadata for RAW/DNG
raw-decode-xmp	zenraw	Yes	No	XMP metadata for RAW/DNG
raw-decode-gainmap	zenraw	Yes	No	Gain map from DNG/AMPF
riapi	—	—	—	RIAPI codec key parsing
zennode	zennode	—	—	Pipeline node definitions
calibrate	(meta)	—	—	All lossy encoders for quality calibration
all	(meta)	Yes	Yes	All codecs and features

Default features: jpeg, webp, gif, gif-zenquant, png, png-zenquant, avif-decode, avif-encode, jxl-decode, heic-decode, bitmaps-bmp.

What This Crate Does

• Format detection from magic bytes
• Image probing (dimensions, format, color info) without full decode
• Typed pixel buffer encode/decode with automatic format negotiation
• Runtime codec registry for per-request codec control
• Resource limits and cooperative cancellation forwarded to codecs
• Format-specific codec configuration via CodecConfig

What This Crate Does Not Do

• Image processing (resize, crop, rotate)
• Color management (ICC profile application)

Image tech I maintain

State of the art codecs*	zenjpeg · zenpng · zenwebp · zengif · zenavif (rav1d-safe · zenrav1e · zenavif-parse · zenavif-serialize) · zenjxl (jxl-encoder · zenjxl-decoder) · zentiff · zenbitmaps · heic · zenraw · zenpdf · ultrahdr · mozjpeg-rs · webpx
Compression	zenflate · zenzop
Processing	zenresize · zenfilters · zenquant · zenblend
Metrics	zensim · fast-ssim2 · butteraugli · resamplescope-rs · codec-eval · codec-corpus
Pixel types & color	zenpixels · zenpixels-convert · linear-srgb · garb
Pipeline	zenpipe · zencodec · zencodecs · zenlayout · zennode
ImageResizer	ImageResizer (C#) — 24M+ NuGet downloads across all packages
Imageflow	Image optimization engine (Rust) — .NET · node · go — 9M+ NuGet downloads across all packages
Imageflow Server	The fast, safe image server (Rust+C#) — 552K+ NuGet downloads, deployed by Fortune 500s and major brands

_{* as of 2026}

General Rust awesomeness

archmage · magetypes · enough · whereat · zenbench · cargo-copter

And other projects · GitHub @imazen · GitHub @lilith · lib.rs/~lilith · NuGet (over 30 million downloads / 87 packages)

License

Dual-licensed: AGPL-3.0 or commercial.

I've maintained and developed open-source image server software — and the 40+ library ecosystem it depends on — full-time since 2011. Fifteen years of continual maintenance, backwards compatibility, support, and the (very rare) security patch. That kind of stability requires sustainable funding, and dual-licensing is how we make it work without venture capital or rug-pulls. Support sustainable and secure software; swap patch tuesday for patch leap-year.

Our open-source products

Your options:

• Startup license — $1 if your company has under $1M revenue and fewer than 5 employees. Get a key →
• Commercial subscription — Governed by the Imazen Site-wide Subscription License v1.1 or later. Apache 2.0-like terms, no source-sharing requirement. Sliding scale by company size. Pricing & 60-day free trial →
• AGPL v3 — Free and open. Share your source if you distribute.

See LICENSE-COMMERCIAL for details.