EVT_ACX_STREAMAUDIOENGINE_ASSIGN_LOOPBACK_PROTECTION callback function (acxelements.h)

Article
02/22/2024

The EVT_ACX_STREAMAUDIOENGINE_ASSIGN_LOOPBACK_PROTECTION callback is implemented by the driver and is called when the loopback protection status is set for an audio engine node.

Syntax

EVT_ACX_STREAMAUDIOENGINE_ASSIGN_LOOPBACK_PROTECTION EvtAcxStreamaudioengineAssignLoopbackProtection;

NTSTATUS EvtAcxStreamaudioengineAssignLoopbackProtection(
  ACXSTREAMAUDIOENGINE StreamAudioEngine,
  ACX_CONSTRICTOR_OPTION ConstrictorOption
)
{...}

Parameters

StreamAudioEngine

An existing, initialized, ACXSTREAMAUDIOENGINE object. For more information about ACX objects, see Summary of ACX Objects.

ConstrictorOption

The ACX_CONSTRICTOR_OPTION that specifies the loopback protection status of the stream audio engine. The status can either be set to AcxConstrictorOptionNone or AcxConstrictorOptionMute. If there are any active streams with AcxConstrictorOptionMute in effect, then the loopback tap for this audio output will emit silence. If all the active stream have AcxConstrictorOptionNone in effect, then the loopback tap contains meaningful data.

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.

EVT_ACX_STREAMAUDIOENGINE_ASSIGN_LOOPBACK_PROTECTION        CodecR_EvtAcxStreamAudioEngineAssignLoopbackProtection;

NTSTATUS
CodecR_EvtAcxStreamAudioEngineAssignLoopbackProtection(
    _In_    ACXSTREAMAUDIOENGINE    StreamAudioEngine,
    _In_    ACX_CONSTRICTOR_OPTION  ConstrictorOption
)
{
    NTSTATUS status = STATUS_INVALID_PARAMETER;
    ACXSTREAM stream;
    PCODEC_STREAM_CONTEXT ctx;
    CRenderStreamEngine * streamEngine = NULL;

    PAGED_CODE();

    stream = AcxStreamAudioEngineGetStream(StreamAudioEngine);
    if (stream)
    {
        ctx = GetCodecStreamContext(stream);

        streamEngine = static_cast<CRenderStreamEngine*>(ctx->StreamEngine);

        status = streamEngine->SetLoopbackProtection(ConstrictorOption);
    }

    return status;
}

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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