zenrav1e

AV1 encoder optimized for still and animated AVIF images. Fork of rav1e by Imazen.

Fork of rav1e

All changes are additive on top of upstream rav1e.

Encoding features

• Quantization matrices — frequency-dependent quantization weights, ~10% BD-rate improvement
• Filter intra prediction — 5 recursive filter modes, auto-enabled at speed <= 6
• Trellis quantization (experimental, disabled by default — marginal gains at +34% encode time)
• Variance adaptive quantization (VAQ) (experimental, disabled by default)
• Tune::StillImage mode — tuning preset for photographic content
• Lossless mode — mathematically lossless encoding via quantizer: 0
• Cooperative cancellation — enough::Stop support behind the stop feature

Modernization

• Rust 2024 edition (MSRV 1.89)
• safe_unaligned_simd for safe SIMD load/store in entropy coding

All upstream rav1e video encoding capabilities are preserved.

Usage

zenrav1e is a library. If you want to encode AVIF images, use ravif or zenavif, which wrap zenrav1e with a higher-level API.

For direct use:

use zenrav1e::prelude::*;

let mut enc = EncoderConfig::default();
enc.width = 640;
enc.height = 480;
enc.speed_settings = SpeedSettings::from_preset(6);
enc.still_picture = true;
enc.enable_qm = true;  // quantization matrices

let cfg = Config::new().with_encoder_config(enc);
let mut ctx: Context<u8> = cfg.new_context().unwrap();
// send frames, receive packets...

Building

# Pure Rust (no asm) — primary development target
cargo check --no-default-features --features threading
cargo test --no-default-features --features threading

# With x86_64 asm (requires nasm)
cargo check --features threading

Requires Rust 1.89+. The asm feature needs NASM 2.14.02+ on x86_64.

Image tech I maintain

* 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.

Upstream code from xiph/rav1e is licensed under BSD-2-Clause. Our additions and improvements are dual-licensed (AGPL-3.0 or commercial) as above.

Upstream Contribution

We are willing to release our improvements under the original BSD-2-Clause license if upstream takes over maintenance of those improvements. We'd rather contribute back than maintain a parallel codebase. Open an issue or reach out.