Sonora

Pure Rust implementation of WebRTC audio processing, providing echo cancellation, noise suppression, and automatic gain control.

Ported from the WebRTC Native Code (M145) audio processing module.

Crates

Features

• Echo Cancellation (AEC3) -- adaptive filter-based echo canceller with delay estimation
• Noise Suppression -- Wiener filter-based noise reduction with voice activity detection
• Automatic Gain Control (AGC2) -- RNN VAD-based gain controller with limiter
• High-Pass Filter -- DC offset removal
• C API -- cbindgen-generated C header for FFI integration (via sonora-ffi)

Quick Start

Run the minimal echo cancellation demo:

cargo run -p sonora --example simple

More examples in crates/sonora/examples/:

The karaoke and recording examples require the examples feature which pulls in cpal, hound, and other audio I/O dependencies. These examples are based on the tonarino/webrtc-audio-processing examples, ported from PortAudio to cpal.

Supported Platforms

Runtime feature detection is used for AVX2 on x86_64. SSE2 is assumed available on all x86_64 targets. NEON is used on AArch64. A scalar fallback is provided for all other architectures.

C++ Integration

The C++ reference test suite (WebRTC M145, 2400+ tests) is validated on Ubuntu x86_64 with the Rust backend linked via the sonora-sys FFI bridge.

Benchmarks

Full pipeline processing a 10 ms frame with AEC3 + noise suppression + AGC2 enabled. Measured on Apple M4 Max (NEON backend), Rust 1.85, -C target-cpu=native:

See BENCHMARKS.md for per-component comparisons, profiling breakdown, and instructions for reproducing.

Development

This project uses cargo-make for task automation.

cargo install cargo-make

Quick start

cargo make ci              # Format, lint, test, docs
cargo make bench           # Rust pipeline benchmarks
cargo make check           # Type-check all crates (including excluded)
cargo make clippy          # Lint all crates (including excluded)

C++ comparison (optional)

cargo make setup           # Install system deps + build C++ library
cargo make cpp-bench       # Run Rust vs C++ comparison benchmarks
cargo make cpp-test        # Run comparison tests
cargo make cpp-validate    # Run 2400+ C++ test suite with Rust backend

See Makefile.toml for the full list of tasks.

Minimum Supported Rust Version

The minimum supported Rust version is 1.91.

Related Projects

• tonarino/webrtc-audio-processing -- Rust bindings to the C++ WebRTC AudioProcessing module. Sonora's examples are based on theirs. If you need the battle-tested C++ implementation with a Rust wrapper, use tonarino; if you want a pure-Rust solution with no C++ dependency, use sonora.
• pulseaudio-wap -- The original extracted C++ code

History

1. Google's libwebrtc -- The original AudioProcessing module is developed as part of the WebRTC Native Code project at Google.

2. PulseAudio's webrtc-audio-processing -- Arun Raghavan and contributors extracted the AudioProcessing module into a standalone library with a Meson build system, making it usable outside of the full WebRTC stack. This packaging is used by PulseAudio, PipeWire, and other Linux audio projects.

3. M145 upgrade and test expansion -- The C++ codebase was updated to WebRTC M145 (branch-heads/7632), the full upstream test suite (2400+ tests) was ported, and the build was upgraded to C++20. (AI assisted)

4. Sonora:Rust port -- The C++ implementation was ported to pure Rust, producing this set of crates. The port includes the full SIMD (SSE2, AVX2, NEON) optimizations and the FFTs, as well as a C API for FFI integration. The full C++ test suite passes against this Rust version. (AI assisted)

License

All crates in this repository are licensed under BSD-3-Clause.