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METransformMarker event

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Sent by an asynchronous Media Foundation transform (MFT) in response to an MFT_MESSAGE_COMMAND_MARKER message.

Event values

Possible values retrieved from IMFMediaEvent::GetValue include the following.

VARTYPE Description
VT_EMPTY
 No event data.

Attributes

The following attributes are defined for this event.

Attribute Description
MF_EVENT_MFT_CONTEXT
 The value of the ulParam parameter from the MFT_MESSAGE_COMMAND_MARKER message.
(Required)

Remarks

Asynchronous MFTs send this event through the IMFMediaEventGenerator interface. Synchronous MFTs never send this event.

The client of an asynchronous MFT can place a marker in the stream by calling IMFTransform::ProcessMessage with the MFT_MESSAGE_COMMAND_MARKER message. The ulParam parameter contains application-defined data.

When the MFT finishes processing all of the input data that was available at the time of the ProcessMessage call, the MFT queues an METransformMarker event. The MF_EVENT_MFT_CONTEXT attribute of the event contains the value of the ulParam parameter. For more information, see Asynchronous MFTs.

Requirements

Requirement Value
Minimum supported client
 Windows 7 [desktop apps only]
Minimum supported server
 Windows Server 2008 R2 [desktop apps only]
Header
Mfobjects.h (include Mfidl.h)

See also

Media Foundation Events

Asynchronous MFTs