| Microsoft DirectX 8.1 (C++) |
The Step method causes the filter graph to step forward by the specified number of frames.
Syntax
HRESULT Step(
DWORD dwFrames,
IUnknown *pStepObject
);
Parameters
dwFrames
Variable of type DWORD specifying the number of frames to skip. If dwFrames is 1, it means step one frame forward. If dwFrames == n and n is greater than 1, it means to skip n - 1 frames and show the nth frame.
pStepObject
Pointer to an interface on the filter that will control the stepping operation. Specify NULL to instruct the Filter Graph Manager to perform frame stepping using the renderer filter for that particular filter graph. If the graph includes a custom filter that implements the frame stepping, then pStepObject should point to that filter's IBaseFilter interface.
Return Values
Returns an HRESULT. Possible values include the following.
| Value | Description |
| S_OK | Success. |
| VFW_E_FRAME_STEP_UNSUPPORTED | Frame stepping is not supported. |
| E_INVALIDARG | The pStepObject parameter is invalid. |
Remarks
When the step operation is complete, this method sends an EC_STEP_COMPLETE event notification to the filter graph manager, which will pass it to the application's event loop and set the filter graph to a paused state.
See Also