Steam Audio active

libmysofa

Standalone

libmysofa is a C library for reading and processing Head-Related Transfer Function (HRTF) data stored in AES SOFA files conforming to the AES69-2015 standard. It provides functions to load SOFA files, extract HRTF filters for specific spatial coordinates, and convert between Cartesian and spherical coordinate systems. The library handles automatic normalization of HRTF data, nearest-neighbor interpolation for arbitrary listener positions, and efficient caching of multiple SOFA files. It supports both integer and floating-point filter extraction with configurable sample rates and neighbor search parameters. Designed for integration into spatial audio engines and renderers, libmysofa offers both simple and advanced APIs for developers who need direct access to HRTF data without implementing SOFA parsing from scratch.

Microsoft Spatializer

Unity

A cross-platform spatializer plugin that integrates spatial audio processing into Unity projects. The plugin uses efficient DSP algorithms to render head-related transfer functions (HRTF) for immersive 3D audio positioning. Designed to fit Unity's audio engine architecture, it supports both Windows and Android platforms. Version 2.0 represents a complete rewrite focused on performance optimization and cross-platform compatibility. The plugin uses a multi-source mixer architecture that reduces CPU overhead compared to previous implementations. While an older HoloLens 2-specific version (v1) offered hardware DSP offload, the current version prioritizes flexibility and integration with Unity's audio pipeline. Note: the GitHub repository was archived (made read-only) in July 2024 and is no longer actively developed, though it remains usable for existing projects. It enables realistic directional audio cues essential for VR, AR, and immersive gaming experiences.

Project Acoustics

Unreal · Unity · Wwise

Project Acoustics is a wave-based acoustics simulation system that bakes acoustic propagation into pre-computed data files. It models occlusion, obstruction, portalling, and reverberation using physics-based wave simulation during an offline baking process, then provides runtime queries for interpolated acoustic parameters. The system uses the Triton engine for voxel-free interpolation and supports multiple ACE files simultaneously. It includes HRTF processing validated through FLEX listening tests published in the Journal of the Acoustic Engineering Society. Runtime performance remains efficient by querying pre-baked simulations rather than computing wave propagation in real-time. Integrations provide spatial reverb, custom impulse responses, and parameter exposure to engine-native systems. The tool handles large worlds through double-precision mesh parsing and supports both middleware and engine-native audio pipelines.

Resonance Audio

Unity · Wwise · FMOD · Standalone

Resonance Audio is a spatial audio SDK that provides HRTF-based binaural rendering, ambisonic encoding/decoding, and room modeling. Originally developed by Google and released as open source, it offers cross-platform support with integrations for Unity, Wwise, FMOD, and VST. The SDK includes tools for geometrical acoustics simulation, reverberation estimation from game geometry, and ambisonic soundfield capture. It supports first-order and higher-order ambisonics, room effects modeling, and binaural rendering using the SADIE HRTF database. The codebase is written in C++ and provides bindings for multiple platforms including desktop, mobile (Android/iOS), and various audio middleware systems. Note: Google archived the GitHub repository in November 2023, so it is no longer actively maintained, though all source code, build scripts, and platform integrations remain available under an open source license.