Concentus-Unity: Opus for Unity C#
This project is a fork of Concentus v2.2.2, retargeted to compile against .NET Standard 2.1, fixing a Span<T> runtime incompatibility on Unity's modern Mono/CLR.
Concentus-Unity is an independent, unofficial fork. It is not affiliated with or endorsed by the original Concentus maintainers or by Unity Technologies; "Unity" in the name refers to compatibility with the Unity engine runtime.
This is a minimal retargeting fork, with no functional or API changes beyond what was required to compile under .NET Standard 2.1. Namespaces have been renamed from Concentus to ConcentusUnity to avoid assembly/namespace collisions when both the original Concentus and this fork are present in the same process.
Why this fork exists
If you've hit MissingMethodException referencing a Span<T>-based method when using Concentus in Unity, this is why.
The original Concentus targets .NET Standard 2.0, which has no native Span<T> support, so it relies on the System.Memory NuGet polyfill package instead. On runtimes that supply Span<T> natively (such as Unity's modern Mono/CLR), this causes a type-identity mismatch between the polyfilled Span<T> Concentus was compiled against and the native Span<T> actually present at runtime, resulting in a MissingMethodException for any Span-based method, even though the method clearly exists in the assembly's metadata.
Retargeting to .NET Standard 2.1 resolves this: Span<T> is supplied natively by the runtime with no polyfill involved, so the type identity matches consumers running on modern .NET/Mono runtimes.
Project status
This fork inherits its Opus implementation directly from Concentus v2.2.2, which itself is based on libopus master 1.1.2 (FIXED_POINT, with optional floating-point analysis) and includes a port of the libspeexdsp resampler. See the original Concentus repository for details on the upstream implementation, testing methodology, and performance characteristics. None of that work has been redone or re-verified independently for this fork; only the target framework and namespaces have changed.
License
This project is licensed under the same BSD-style license as the original Concentus project. See LICENSE for the full text and original copyright holders.
