Concentus Unity

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 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-based method when using Concentus in Unity, this is why.

The original Concentus targets.NET Standard 2.0, which has no native Span support, so it relies on the System.Memory NuGet polyfill package instead. On runtimes that supply Span natively (such as Unity's modern Mono/CLR), this causes a type-identity mismatch between the polyfilled Span Concentus was compiled against and the native Span 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 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.