Skip to content

Latest commit

 

History

History
134 lines (102 loc) · 5.02 KB

nf-acxstreams-acxrtstreamcreate.md

File metadata and controls

134 lines (102 loc) · 5.02 KB
Raw
UID tech.root title ms.date targetos description prerelease req.assembly req.construct-type req.ddi-compliance req.dll req.header req.idl req.include-header req.irql req.kmdf-ver req.lib req.max-support req.namespace req.redist req.target-min-winverclnt req.target-min-winversvr req.target-type req.type-library req.umdf-ver req.unicode-ansi topic_type api_type api_location api_name f1_keywords dev_langs
NF:acxstreams.AcxRtStreamCreate
audio
AcxRtStreamCreate
12/16/2022
Windows
AcxRtStreamCreate creates an ACX RT-based Stream that is used by the OS to stream audio data.
false
function
acxstreams.h
PASSIVE_LEVEL
apiref
HeaderDef
acxstreams.h
AcxRtStreamCreate
AcxRtStreamCreate
acxstreams/AcxRtStreamCreate
c++

-description

AcxRtStreamCreate creates an ACX RTStream audio stream that is used by the OS to stream audio data.

-parameters

-param Device

A WDFDEVICE object (described in Summary of Framework Objects) that is associated with the specified ACXCIRCUIT and its stream.

-param Circuit

The ACXCIRCUIT that this stream will be associated with.

-param Attributes

Additional Attributes defined using a WDF_OBJECT_ATTRIBUTES that are used to set the various object's values: cleanup and destroy callbacks, context type, and to specify its parent object.

-param Config

An ACXSTREAM_INIT structure that defines the initialization parameters of the stream. For more information about ACX Objects, see ACX - Summary of ACX Objects.

-param Stream

A pointer to a location that receives a handle to the new ACXSTREAM Object.

An ACXSTREAM object represents an audio stream created by a circuit. For more information, see ACX - Summary of ACX Objects.

-returns

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

-remarks

After the ACXSTREAM has been created, the driver can add one or more ACX elements to the stream. By default, ACX elements are connected in the same order of assembly. An ACXSTREAM is associated with only one ACXCIRCUIT. ACX supports two types of streams: basic ACX stream objects used by non-streaming circuits, and ACX RealTime (RT) stream objects used by streaming circuits.

The ACXSTREAM created by AcxRtStreamCreate will allow the driver to receive control signals and state changes associated with a stream. The ACXSTREAM will also support streaming audio data to or from the OS. A driver that supports streaming audio data should use AcxRtStreamCreate to create an ACXSTREAM with support for streaming.

For an endpoint that is made from multiple ACXCIRCUITs across multiple drivers, the ACXCIRCUIT that hosts the streaming pin would create an ACX RT Stream while the other ACXCIRCUITs in the endpoint would create non-RT ACX Streams.

Example

Example Rt stream creation is shown below.

    //
    // Init streaming callbacks.
    //
    ACX_STREAM_CALLBACKS streamCallbacks;
    ACX_STREAM_CALLBACKS_INIT(&streamCallbacks);
    streamCallbacks.EvtAcxStreamPrepareHardware     = EvtStreamPrepareHardware;
    streamCallbacks.EvtAcxStreamReleaseHardware     = EvtStreamReleaseHardware;
    streamCallbacks.EvtAcxStreamRun                 = EvtStreamRun;
    streamCallbacks.EvtAcxStreamPause               = EvtStreamPause;
    streamCallbacks.EvtAcxStreamAssignDrmContentId  = EvtStreamAssignDrmContentId;

    status = AcxStreamInitAssignAcxStreamCallbacks(StreamInit, &streamCallbacks);

    //
    // Init RT Streaming callbacks.
    //
    ACX_RT_STREAM_CALLBACKS rtCallbacks;
    ACX_RT_STREAM_CALLBACKS_INIT(&rtCallbacks);
    rtCallbacks.EvtAcxStreamGetHwLatency = EvtStreamGetHwLatency;
    rtCallbacks.EvtAcxStreamAllocateRtPackets = EvtStreamAllocateRtPackets;
    rtCallbacks.EvtAcxStreamFreeRtPackets = EvtStreamFreeRtPackets;
    rtCallbacks.EvtAcxStreamSetRenderPacket = EvtStreamSetRenderPacket;
    rtCallbacks.EvtAcxStreamGetCurrentPacket = EvtStreamGetCurrentPacket;
    rtCallbacks.EvtAcxStreamGetPresentationPosition = EvtStreamGetPresentationPosition;

    status = AcxStreamInitAssignAcxRtStreamCallbacks(StreamInit, &rtCallbacks);

    //
    // Create the stream.
    //
    WDF_OBJECT_ATTRIBUTES attributes;
    ACXSTREAM stream;
    WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE(&attributes, STREAM_CONTEXT);
    attributes.EvtCleanupCallback = EvtStreamContextCleanup;
    attributes.EvtDestroyCallback = EvtStreamDestroy;
    status = AcxRtStreamCreate(Device, Circuit, &attributes, &StreamInit, &stream);

ACX requirements

Minimum ACX version: 1.0

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

-see-also