METransformMarker event
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 |
|
See also