IApoAcousticEchoCancellation interface (audioenginebaseapo.h)

This interface is implemented by APOs to enable acoustic echo cancellation (AEC) scenarios.

Inheritance

The IApoAcousticEchoCancellation interface inherits from the IUnknown interface.

Remarks

This interface may only be implemented by mode effects (MFX) on capture endpoints. Implementing this interface on any other APO will lead to a failure in loading that APO. If the mode effect on a capture endpoint is implemented as a series of chained APOs, only the APO closest to the device may implement this interface.

The IApoAcousticEchoCancellation interface has no explicit methods on it. Its purpose is to identify an AEC APO to the audio engine. APOs that implement this interface will be passed an APO_CONNECTION_PROPERTY_V2 structure in its call to IAudioProcessingObjectRT::APOProcess. APO_CONNECTION_PROPERTY_V2 provides a timestamp to allow the APO to synchronize buffers from the primary and auxiliary streams. If the u32Signature field of the APO_CONNECTION_PROPERTY structure passed into IAudioProcessingObjectRT::APOProcess is equal to APO_CONNECTION_PROPERTY_V2_SIGNATURE, the structure can be safely typecast to a APO_CONNECTION_PROPERTY_V2.

Because AEC algorithms typically require specific sampling rates and channel counts, the audio engine provides resampling support to APOs that implement the IApoAcousticEchoCancellation interface. The IApoAuxiliaryInputConfiguration::IsInputFormatSupported method provides a mechanism for informing the system of the APO's preferred input format by returning the HRESULT APOERR_FORMAT_NOT_SUPPORTED. and returning the requested format in the method's ppSupportedInputFormat parameter. The audio engine will then resample input audio to the suggested format prior to sending it to the AEC APO. This eliminates the need for the AEC APO to implement sampling rate and channel count conversion.

Requirements

Requirement	Value
Minimum supported client	Windows 10 Build 20348
Header	audioenginebaseapo.h

See also

APO_CONNECTION_PROPERTY_V2 IAudioProcessingObjectRT::APOProcess IAudioProcessingObject::IsInputFormatSupported