QuickTime 3 Reference
A color value, plus a specification of the color space it belongs to, constitute a color. A color is a structure defined by the gxColor type definition:
struct gxColor{
gxColorSpace space;
gxColorProfile profile;
union {
struct gxCMYKColor cmyk;
struct gxRGBColor rgb;
struct gxRGBAColor rgba;
struct gxHSVColor hsv;
struct gxHLSColor hls;
struct gxXYZColor xyz;
struct gxYXYColor yxy;
struct gxLUVColor luv;
struct gxLABColor lab;
struct gxYIQColor yiq;
gxColorValue gray;
struct gxGrayAColor graya;
unsigned short pixel16;
unsigned long pixel32;
struct gxIndexedColor indexed;
gxColorValue component[4];
} element;
};