IAMVideoProcAmp Interface

Description

Provides programmatic control over the following camera properties: black level, gain, gamma, white balance.


Methods

HRESULT Get ( long Property, long *pValue, long *Flags )

Retrieves the value of a specific camera control property.

HRESULT Set ( long Property, long lValue, long Flags );

Sets the value of a specific camera control property.

HRESULT GetRange ( long Property, long *pMin, long *pMax, long *pSteppingDelta, long *pDefault, long *pFlags );

Retrieves values associated with the range of a specified camera property.

Parameters

Property

[in] Value that specifies the camera property. Use one of the following values:

        

VideoProcAmp_Brightness - to set and retrieve the camera's black level setting.

VideoProcAmp_Gain - to control the camera's gain.

VideoProcAmp_Gamma - to control the camera's gamma setting.

VideoProcAmp_WhiteBalance - to control the camera's white balance.

pValue / lValue

[in/out] New value or pointer to the value of the specified property.

pValue

[in] New value of the specified property.

pMin

[out] Pointer to the minimum range for the specified property.

pMax

[out] Pointer to the maximum range for the specified property.

pSteppingDelta

[out] Pointer to the step size for the specified property.

pDefault

[out] Pointer to the default value of the specified property.

Flags / pFlags

[in/out] Value or pointer to the value indicating whether the camera property is automatic or manual:

VideoProcAmp_Flags_Auto - sets the property's automatic flag.

VideoProcAmp_Flags_Manual - sets the property's manual flag.

Return Values

S_OK

Success

E_FAIL

Failure.

E_INVALIDARG

Invalid argument.

Example

This C++ code request a pointer to IAMVideoProcAmp interface from the video capture filter, initiates the automatic gain control and sets the black level value to 64:

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

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