EVT_ACX_STREAMAUDIOENGINE_RETRIEVE_LINEAR_BUFFER_POSITION callback function (acxelements.h)

Article
02/22/2024

The EVT_ACX_STREAMAUDIOENGINE_RETRIEVE_LINEAR_BUFFER_POSITION callback is implemented by the driver and is called when the linear buffer position is requested for the specified stream audio engine.

Syntax

EVT_ACX_STREAMAUDIOENGINE_RETRIEVE_LINEAR_BUFFER_POSITION EvtAcxStreamaudioengineRetrieveLinearBufferPosition;

NTSTATUS EvtAcxStreamaudioengineRetrieveLinearBufferPosition(
  ACXSTREAMAUDIOENGINE StreamAudioEngine,
  PULONGLONG Position
)
{...}

Parameters

StreamAudioEngine

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

Position

A ULONGLONG value that represents the number of bytes that the DMA has fetched from the audio buffer of the specified stream audio engine since the beginning of the stream.

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_RETRIEVE_LINEAR_BUFFER_POSITION   CodecR_EvtAcxStreamAudioEngineRetrieveLinearBufferPosition;

NTSTATUS
CodecR_EvtAcxStreamAudioEngineRetrieveLinearBufferPosition(
    _In_    ACXSTREAMAUDIOENGINE    StreamAudioEngine,
    _Out_   PULONGLONG              Position
)
{
    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->GetLinearBufferPosition(Position);
    }

    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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