This section describes these analog video functions. The VDGetVideoDefaults function returns the suggested default values for the analog video parameters that can be affected by functions described in this section. A number of functions affect gamma correction. You can use the VDSetInputGammaValue and VDGetInputGammaValue functions to allow your application to set particular gamma values. The VDSetBlackLevelValue , VDGetBlackLevelValue , VDSetWhiteLevelValue , and VDGetWhiteLevelValue functions allow applications to work with black levels and white levels in the source video.
Black level refers to the degree of blackness in an image.
This is a common setting on a video digitizer. Black level is a significant setting because it can be adjusted so that there is little or no noise in an image. White level refers to the degree of whiteness in an image. It is also a common video digitizer setting. The VDSetContrast , VDGetContrast , VDSetSharpness , and VDGetSharpness functions allow applications to work with contrast and sharpness values in the source video.