IAMVideoControl Interface

Description

Provides an ability to flip a picture horizontally and/or vertically, set up a trigger mode, issue the software trigger, and list the available frame rates.


Methods

HRESULT GetMode ( IPin *pPin, long *pFlags )

Retrieves the video control properties.

HRESULT SetMode ( IPin *pPin, long Flags )

Sets the video control properties.

HRESULT GetCaps ( IPin *pPin, long *pFlags )

Requests availability of the video control properties.

HRESULT GetCurrentActualFrameRate ( IPin *pPin, LONGLONG *pFrameRate )

Retrieves the actual frame rate, expressed as a frame duration in 100-nanosecond units.

HRESULT GetFrameRateList ( IPin *pPin, long iIndex, SIZE Dimensions, long *ListSize, LONGLONG **FrameRates )

Retrieves a list of available frame rates for the specified video mode.

HRESULT GetMaxAvailableFrameRate( IPin *pPin, long iIndex, SIZE Dimensions, LONGLONG *pFrameRate )

Retrieves the maximum frame rate available for the specified video mode.

Parameters

pPin

[in] Pointer to the video capture pin.

pFlags / Flags

[in/out] New value or pointer to the value specifying a combination of the video control flags:

VideoControlFlag_FlipHorizontal - specifies that the picture is flipped horizontally.

VideoControlFlag_FlipVertical - specifies that the picture is flipped vertically.

VideoControlFlag_ExternalTriggerEnable - specifies that the camera is set to the trigger mode.

VideoControlFlag_Trigger - issues a software trigger signal.

pFrameRate

[in/out] Pointer to the frame rate. The frame rate is expressed as frame duration in 100-nanosecond units.

iIndex

[in] Index of the video mode to query for the frame rates.

Dimensions

[in] Frame image size (width and height) in pixels

ListSize

[out] Pointer to the number of elements in the list of frame rates.

FrameRates

[in] Address of a pointer to an array of frame rates in 100-nanosecond units.

Return Values

S_OK

Success

E_FAIL

Failure.

E_INVALIDARG

Invalid argument.

Example

This C++ code request a pointer to IAMVideoControl interface from the video capture filter, and sets the camera into the trigger mode with the horizontal image flipping:

IAMVideoProcAmp *pVideoControl;
HRESULT hr;
hr = pFilter->QueryInterface(IID_IAMVideoControl, (void **)&pVideoControl);
if(hr==S_OK)
{
   hr=pVideoControl->Set(VideoProcAmp_Gain,0,VideoProcAmp_Flags_Auto);
   hr=pVideoControl->Set(VideoProcAmp_Brightess,64,VideoProcAmp_Flags_Manual);
}
Remarks

IAMVideoControl is a standard DirectShow interface. Refer to Microsoft DirectX SDK documentation for more details.