| Microsoft DirectX 8.1 (C++) |
The CanStep method determines the stepping capabilities of the specified filter.
Syntax
HRESULT CanStep(
long bMultiple,
IUnknown *pStepObject
);
Parameters
bMultiple
If bMultiple is specified as 0 and the method returns S_OK, it means the object can step one frame at a time. If bMultiple if greater than 0, and the method returns S_OK, it means that pStepObject can step bMultiple frames at a time.
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 S_OK if the object can step or E_INVALIDARG if pStepObject is invalid.
Remarks
The frames step in real time, which means that if the movie is playing at 30 frames per second, calling IVideoFrameStep::Step with bMultiple set to 60 would take 2 seconds to execute. All methods in this interface are asynchronous, so control returns to the application immediately.
See Also