Developer Documentation

QuickTime 4 API Documentation

QuickTime 4 Reference

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Media Video Parameters

The whichparam parameter to the MediaSetVideoParam and MediaGetVideoParam functions specifies which video parameter you want to adjust. QuickTime defines these constants that you can use to configure the whichparam parameter.

enum {
    kMediaVideoParamBrightness  = 1,
    kMediaVideoParamContrast    = 2,
    kMediaVideoParamHue         = 3,
    kMediaVideoParamSharpness   = 4,
    kMediaVideoParamSaturation  = 5,
    kMediaVideoParamBlackLevel  = 6,
    kMediaVideoParamWhiteLevel  = 7
};

Constant descriptions

kMediaVideoParamBrightness
The brightness value controls the overall brightness of the digitized video image. Brightness values range from 0 to 65,535, where 0 is the darkest possible setting and 65,535 is the lightest possible setting.

kMediaVideoParamContrast
The contrast value ranges from 0 to 65,535, where 0 represents no change to the basic image and larger values increase the contrast of the video image (that is, increase the slope of the transform).

kMediaVideoParamHue
Hue is similar to the tint control on a television. It is specified in degrees with complementary colors set 180 degrees apart (red is 0°, green is +120°, and blue is -120°). QuickTime supports hue values that range from 0 (-180° shift in hue) to 65,535 (+179° shift in hue), where 32,767 represents a 0° shift in hue.

kMediaVideoParamSharpness
The sharpness value ranges from 0 to 65,535, where 0 represents no sharpness filtering and 65,535 represents full sharpness filtering. Higher values result in a visual impression of increased picture sharpness

kMediaVideoParamSaturation
The saturation value controls color intensity. For example, at high saturation levels, red appears to be red; at low saturation, red appears pink. Valid saturation values range from 0 to 65,535, where 0 is the minimum saturation value and 65,535 specifies maximum saturation.

kMediaVideoParamBlackLevel
Black level refers to the degree of blackness in an image.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 values range from 0 to 65,535, where 0 represents the maximum black value and 65,535 represents the minimum black value.

kMediaVideoParamWhiteLevel
White level refers to the degree of whiteness in an image. White level values range from 0 to 65,535, where 0 represents the minimum white value and 65,535 represents the maximum white value

© 1999 Apple Computer, Inc.

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