Inside Macintosh: QuickTime Components /

Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Controlling Analog Video

VDGetInputGammaRecord

The VDGetInputGammaRecord function allows your application to retrieve a pointer to the active input gamma structure. Gamma structures give applications complete control over color filtering transforms and are therefore more precise than the gamma values that can be set by calling the VDSetInputGammaValue function (described in the next section).

pascal VideoDigitizerError VDGetInputGammaRecord
                            (VideoDigitizerComponent ci,
                               VDGamRecPtr *inputGammaPtr);

ci

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

inputGammaPtr

Contains a pointer to a field that is to receive a pointer to an input gamma structure. The input gamma structure is defined by the gammaTbl data type. For more information about gamma structures, see Designing Cards and Drivers for the Macintosh Family, third edition. The video digitizer component places a pointer to its input gamma structure into the field referred to by this parameter.

RESULT CODES

noErr	0	No error
digiUnimpErr	-2201	Function not supported

SEE ALSO

Your application can set the input gamma structure by calling the VDSetInputGammaRecord function, which is described in the previous section.

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