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Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Controlling Analog Video

VDSetInputGammaValue

The VDSetInputGammaValue function sets the gamma values. These gamma values control the brightness of the input video signal. Your application can implement special color effects, such as turning off specific color channels, by calling this function.

pascal VideoDigitizerError VDSetInputGammaValue
                               (VideoDigitizerComponent ci,
                                 Fixed channel1, 
                                 Fixed channel2, 
                                 Fixed channel3);

ci

Specifies the video digitizer component for the request. Applications obtain this reference from the Component Manager's OpenComponent function.

channel1

Specifies the gamma value for the red component of the input
video signal.

channel2

Specifies the gamma value for the green component of the input
video signal.

channel3

Specifies the gamma value for the blue component of the input
video signal.

RESULT CODES

noErr	0	No error
digiUnimpErr	-2201	Function not supported

SEE ALSO

Your application can retrieve the current gamma values by calling the VDGetInputGammaValue function (described in the next section). To obtain the recommended gamma values, your application can call the VDGetVideoDefaults function (described on page 8-66).