XAudio2

XAudio2 is a low-level audio API developed by Microsoft as part of the DirectX suite, designed for high-performance, real-time audio rendering in games and multimedia applications. It provides a flexible, buffer-based model that supports low-latency playback, mixing, streaming, and effects. XAudio2 is used on Windows and Xbox consoles and is the successor to the earlier XAudio versions.

The API centers on a graph of voices. The MasteringVoice represents the final mix destination, SubmixVoice groups several inputs for collective processing, and SourceVoice represents individual audio streams. Developers create a XAudio2 engine instance, typically via XAudio2Create, then create mastering, submix, and source voices with appropriate audio formats (typically described by a WAVEFORMATEX structure). Audio data is submitted to SourceVoice buffers, which are started and stopped as needed. Volume, pitch, and routing can be controlled on a per-voice basis, and multiple voices can be mixed in real time.

XAudio2 supports 3D audio through the X3DAudio library, which computes positional audio data for listener and emitter objects. This data can be applied to SourceVoice parameters to achieve spatialized effects. The API also supports processing objects known as XAPOs for effects such as reverb, EQ, and delay, which can be attached to voices or submixes.

Platform support and usage notes: XAudio2 is part of DirectX and is available on Windows and Xbox consoles. It is exposed as a COM-based API with language wrappers for C/C++, and is commonly used in game engines and multimedia applications where fine-grained control over audio playback, timing, and spatialization is required.