EVT_ACX_AUDIOENGINE_RETRIEVE_ENGINE_FORMAT callback function (acxelements.h)

Artikel
02/22/2024

The EVT_ACX_AUDIOENGINE_RETRIEVE_ENGINE_FORMAT callback is implemented by the driver and is called when the internal mix format is requested for the specified audio engine.

Syntax

EVT_ACX_AUDIOENGINE_RETRIEVE_ENGINE_FORMAT EvtAcxAudioengineRetrieveEngineFormat;

NTSTATUS EvtAcxAudioengineRetrieveEngineFormat(
  ACXAUDIOENGINE AudioEngine,
  ACXDATAFORMAT *Format
)
{...}

Parameters

AudioEngine

The ACXAUDIOENGINE object for which the mix format has been requested. For more information about ACX objects, see Summary of ACX Objects.

Format

The ACXDATAFORMAT object that describes the audio engine mix format.

Return value

Returns STATUS_SUCCESS if the call was successful. Otherwise, it returns an appropriate error code. For more information, see Using NTSTATUS Values.

Remarks

Example

Example usage is shown below.

typedef struct _CODEC_ENGINE_CONTEXT {
    ACXDATAFORMAT   MixFormat;
    BOOLEAN         GFxEnabled;
} CODEC_ENGINE_CONTEXT, *PCODEC_ENGINE_CONTEXT;

WDF_DECLARE_CONTEXT_TYPE_WITH_NAME(CODEC_ENGINE_CONTEXT, GetCodecEngineContext)

EVT_ACX_AUDIOENGINE_RETRIEVE_ENGINE_FORMAT      CodecR_EvtAcxAudioEngineRetrieveEngineMixFormat;

NTSTATUS
NTAPI
CodecR_EvtAcxAudioEngineRetrieveEngineMixFormat(
    _In_    ACXAUDIOENGINE  AudioEngine,
    _Out_   ACXDATAFORMAT * Format
    )
{
    PCODEC_ENGINE_CONTEXT   audioEngineCtx;
    PAGED_CODE();

    audioEngineCtx = GetCodecEngineContext(AudioEngine);

    if (!audioEngineCtx->MixFormat)
    {
        return STATUS_INVALID_DEVICE_STATE;
    }

    *Format = audioEngineCtx->MixFormat;

    return STATUS_SUCCESS;
}

ACX requirements

Minimum ACX version: 1.0

For more information about ACX versions, see ACX version overview.

Requirements

Requirement	Value
Header	acxelements.h
IRQL	PASSIVE_LEVEL

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