Controlling Analog Video
Some video digitizer components may provide functions that allow applications to control the characteristics of the input analog video signal. This section describes these analog video functions.The
VDGetVideoDefaultsfunction 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. The
VDSetInputGammaRecordandVDGetInputGammaRecordfunctions work with gamma structures (see Designing Cards and Drivers for the Macintosh Family, third edition, for more information about gamma structures). You can use theVDSetInputGammaValueandVDGetInputGammaValuefunctions to allow your application to set particular gamma values.The
VDSetBlackLevelValue,VDGetBlackLevelValue,VDSetWhiteLevelValue, andVDGetWhiteLevelValuefunctions 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. The highest setting produces an all-black image; on the other hand, the lowest setting yields little, if any, black even with black objects in the scene. 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, andVDGetSharpnessfunctions allow applications to work with contrast and sharpness values in the source video. TheVDGetBrightnessandVDSetBrightnessfunctions allow applications to work with the image brightness setting.The
VDSetHue,VDGetHue,VDSetSaturation, andVDGetSaturationfunctions allow applications to work with hue and saturation settings in the source video.
Subtopics
- VDGetVideoDefaults
- VDSetBlackLevelValue
- VDGetBlackLevelValue
- VDSetWhiteLevelValue
- VDGetWhiteLevelValue
- VDSetHue
- VDGetHue
- VDSetSaturation
- VDGetSaturation
- VDSetBrightness
- VDGetBrightness
- VDSetContrast
- VDGetContrast
- VDSetSharpness
- VDGetSharpness
- VDSetInputGammaRecord
- VDGetInputGammaRecord
- VDSetInputGammaValue
- VDGetInputGammaValue
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