Intel 815 manual Overlay Color Correction Registers

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

R

15.4.7.Overlay Color Correction Registers

Used for YUV sources only. Adjustments are made before the RGB conversion.

15.4.7.1.OV0CLRC0—Overlay 0 Color Correction 0 Register

Memory Address Offset:			48h (R/W)
On-chip Reg. Mem Addr Offset:			30148h (RO; debug path)
Default Value:			00h
Access:			see address offset above
Size:			32 bits
31			17	16	8	7	0
		Reserved		Contrast			Brightness
	Bit			Description
31:17		Reserved.
16:8		Contrast. - 7.3F (3.6 format)
		Bypassing Contrast, even for RGB, is accomplished by programming this field to 1.0
7:0		Brightness. Range ±127 a value of zero disables this adjustment affect. This value gets added to the
		Y value after contrast multiply and just before RGB conversion.

Bypassing Brightness, even for RGB, is accomplished by programming this field to 0.

15.4.7.2.OV0CLRC1—Overlay 0 Color Correction 1 Register

Memory Address Offset:			4Ch (R/W)
On-chip Reg. Mem Addr Offset:			3014Ch (RO; debug path)
Default Value:			00h
Access:			see address offset above
Size:			32 bits
31			10	9	0
			Reserved		Saturation/CrCb
	Bit		Description
31:10		Reserved.
9:0		Saturation/CrCb. This operates in two modes. When YUV data is being operated on, the register
		contains the saturation value. When CbCr data is being used, it is the sum of the saturation multiplier
		value added to the CbCr scale factor (128/112).
		This unsigned fixed point number is in 3.7 format.

Bypassing Saturation, even for RGB, is accomplished by programming this field to 1.0

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