if uint32(b)&0xff000000 == 0 {
		b >>= 8
	} else {
		b = ^(b >> 31) & 0xffff
	}

	return uint32(r), uint32(g), uint32(b), 0xffff
}

// YCbCrModel is the [Model] for Y'CbCr colors.
var YCbCrModel Model = ModelFunc(yCbCrModel)

func yCbCrModel(c Color) Color {
	if _, ok := c.(YCbCr); ok {
		return c
	}
	r, g, b, _ := c.RGBA()
	y, u, v := RGBToYCbCr(uint8(r>>8), uint8(g>>8), uint8(b>>8))

		return image.Config{}, err
	}
	switch d.nComp {
	case 1:
		return image.Config{
			ColorModel: color.GrayModel,
			Width:      d.width,
			Height:     d.height,
		}, nil
	case 3:
		cm := color.YCbCrModel
		if d.isRGB() {
			cm = color.RGBAModel
		}
		return image.Config{
			ColorModel: cm,
			Width:      d.width,
			Height:     d.height,
		}, nil
	case 4:
		return image.Config{