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Spatial Audio Framework

Standalone · Engine-agnostic

An open-source, cross-platform framework for developing spatial audio algorithms in C/C++. Provides modular components for Ambisonics encoding/decoding, spherical array processing, amplitude panning, HRIR/HRTF processing, room simulation, and other spatial audio techniques. Leverages optimized linear algebra libraries (Intel MKL, Apple Accelerate, OpenBLAS) and x86 SIMD intrinsics for performance. The framework includes core modules covering higher-order Ambisonics, spherical harmonics, VBAP, the Covariance Domain Framework, HRIR utilities, and reverb algorithms. Optional modules add SOFA file reading, particle-filtering tracking, and HADES binaural rendering. Originally designed for researchers, it has evolved into a substantial codebase with several example implementations realized as VST/LV2 plugins under the SPARTA project. The modular architecture allows straightforward extension and integration into existing projects via CMake or direct source inclusion. Supports optional Intel IPP for FFT/resampling, FFTW for DFT operations, and NetCDF for large SOFA files.

Omnitone

Standalone

Omnitone is a Web Audio API implementation of ambisonic decoding and binaural rendering. It supports first-order (4-channel) and higher-order ambisonic streams (2nd and 3rd order, up to 16 channels). The library uses native Web Audio nodes for performance-critical processing, ensuring efficient CPU usage. The implementation follows the Google spatial media specification and uses SADIE binaural filters for rendering. It accepts input from HTML media elements or multichannel AudioBufferSourceNodes, with support for dynamic rotation matrices to orient the sound field in response to user interaction or sensor data. Omnitone powers the Resonance Audio SDK for web and provides both ambisonic and bypass rendering modes. The library is designed for browser-based spatial audio applications, VR experiences, and 360-degree video playback. Note: the last release (v1.3.0) was in January 2019, so the project is effectively dormant.

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.

SPARTA

Standalone

SPARTA is a suite of open-source spatial audio plug-ins built on the Spatial Audio Framework. The collection provides comprehensive tools for Ambisonic encoding, decoding, rotation, and analysis, as well as specialized processors for beamforming, binaural rendering, room simulation, and sound-field visualization. Each plug-in supports high-order operations (up to 10th order Ambisonics) and many include SOFA file loading for HRIR/BRIR data and OSC head-tracking integration. The suite covers the full spatial audio pipeline: Array2SH encodes microphone arrays to Ambisonics, AmbiENC provides source panning, AmbiRoomSim adds image-source reflections, and AmbiDEC/AmbiBIN decode to loudspeakers or headphones. Analysis tools like PowerMap, DirASS, and SLDoA visualize directional sound-field characteristics. Additional utilities include dynamic range compression (AmbiDRC), arbitrary spreading (Spreader), VBAP panning, and matrix/multi-channel convolution with partitioned modes. All plug-ins are available as VST, VST3, AU, LV2, and AAX formats for macOS, Linux (x86_64 and ARM), and Windows. The codebase is built with JUCE and distributed under GPLv3, making it suitable for research, production, and custom extensions.