XAudio2 Reference

This section provides detailed reference information for the XAudio2 API, which is a low-level audio API for Windows that provides powerful audio manipulation and mixing capabilities for game developers.

Key Interfaces

The core functionality of XAudio2 is accessed through several key interfaces:

IXAudio2: The central engine interface. Used to create submixes, mastering voices, source voices, and process audio.
IXAudio2MasteringVoice: Represents the output device (e.g., speakers, headphones).
IXAudio2SourceVoice: Represents an audio source (e.g., a sound effect, music track).
IXAudio2SubmixVoice: Used for intermediate processing and mixing of audio streams.

`IXAudio2` Interface

The IXAudio2 interface is the primary entry point for XAudio2 functionality. You obtain an instance of this interface by calling the XAudio2Create function.

Methods

Method	Description
`CreateMasteringVoice(...)`	Creates a mastering voice, which represents the audio output device.
`CreateSourceVoice(...)`	Creates a source voice for playing audio data.
`CreateSubmixVoice(...)`	Creates a submix voice for routing and processing audio streams.
`StartEngine()`	Starts the XAudio2 engine.
`StopEngine()`	Stops the XAudio2 engine.
`CommitChanges()`	Applies all pending audio graph changes.

`IXAudio2MasteringVoice` Interface

The IXAudio2MasteringVoice interface controls the output of audio to the system's audio device. It typically receives audio from other voices (source or submix).

Methods

Method	Description
`GetVoiceDetails(...)`	Retrieves details about the mastering voice.
`SetVolume(...)`	Sets the volume for the mastering voice.
`SetOutputMatrix(...)`	Configures the audio channel routing from the mastering voice to the output device.

`IXAudio2SourceVoice` Interface

The IXAudio2SourceVoice interface is used to play audio samples. It's where you submit audio buffers to be processed and mixed.

Methods

Method	Description
`SubmitSourceBuffer(...)`	Submits an audio buffer to be played.
`Start(...)`	Starts playback on the source voice.
`Stop(...)`	Stops playback on the source voice.
`FlushSourceBuffers()`	Removes all pending audio buffers from the voice.
`SetSourceSampleRate(...)`	Sets the sample rate for the source voice.

`IXAudio2SubmixVoice` Interface

IXAudio2SubmixVoice allows for grouping and processing multiple audio streams before they reach the mastering voice. This is useful for effects chains and advanced mixing.

Methods

Method	Description
`SetEffectChain(...)`	Applies a chain of audio effects to the submix voice.
`EnableEffect(...)`	Enables a specific effect in the chain.
`DisableEffect(...)`	Disables a specific effect in the chain.

Note: This reference provides a high-level overview. For full API details, including parameter descriptions and return values, please consult the official DirectX SDK documentation.

Important: Proper management of audio voices and buffers is crucial for performance and preventing audio glitches. Always ensure voices are destroyed when no longer needed.