Intel 815 manual Overlay Scale Factor Registers, YRGBSCALE-Y/RGB Scale Factor Register

Models: 815

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Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

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15.4.6.Overlay Scale Factor Registers

These registers provide the scaling information that is used to specify the amount of vertical and horizontal scaling. In the case of YUV formats, there are independent scale factors for Y and UV data to compensate for the various formats that include sub-sampled UV data. Up or down scaling is set using the bits of the command word. In the case of down scaling, the integer portion of the scale factor can be up to three in the vertical and is assumed to be one in the horizontal.

15.4.6.1.YRGBSCALE—Y/RGB Scale Factor Register

Memory Address Offset:

 

40h (R/W)

 

 

 

 

 

 

 

On-chip Reg. Mem Addr Offset:

30140h (RO; debug path)

 

 

 

 

 

 

Default Value:

 

00h

 

 

 

 

 

 

 

 

 

Access:

 

 

see address offset above

 

 

 

 

 

 

Size:

 

 

32 bits

 

 

 

 

 

 

 

 

31

20

19

17

16

15

14

3

2

 

1

0

 

 

 

Vertical Scale Factor

Reserved

Horizontal

X Scale Factor Y/RGB

 

Re

 

 

Vertical

 

 

 

 

Y/RGB

 

 

 

Scale

 

 

ser

 

 

Down

 

 

 

 

 

 

 

Factor

 

 

ved

 

 

Scale

 

 

 

 

 

 

 

Y/RGB

 

 

 

 

 

Integer

 

 

 

 

 

 

 

Integer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

31:20

Vertical Scale Factor Y/RGB. This is a fractional positive number that represents the scale factor to

 

 

 

be used in vertical scaling. For packed formats, it applies to all color components and for planar YUV

 

 

 

formats it is use for the Y component only. Always Bit 31:20 1 > scale 1/64 (the maximum vertical up

 

 

 

zoom is 64X) (1/Scale for up scale fractional portion of the scale factor for down scaling)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

19:17

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16:15

Horizontal Scale Factor Y/RGB Integer. This field is used only for horizontal down scale. In the case

 

 

 

of planar formats, it specifies the integer portion of the scale factor for Y data. Only Horizontal down

 

 

 

scaling of 2 (or less) to 1 is supported.

 

 

 

 

 

 

 

 

 

 

 

 

 

14:3

Horizontal Scale Factor Y/RGB. This is a fractional positive number that represents the scale factor

 

 

 

to be used in horizontal scaling. Always 1>scale0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1:0

Vertical Down Scale Integer. This field is used only for vertical down scale. In the case of planar

 

 

 

formats, it specifies the integer portion of the scale factor for Y data.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Page 285
Image 285
Intel 815 manual Overlay Scale Factor Registers, YRGBSCALE-Y/RGB Scale Factor Register