AK8858 Datasheet, PDF (54/96 Pages) Asahi Kasei Microsystems – PS/SD Multi Format Video Decoder

[7.29] Image quality adjustment
Image quality adjustments consist of contrast, brightness, color saturation, and hue adjustment.
[AK8858]
[7.29.1] Contrast adjustment
Setting for contrast adjustment inclination
Register
Definition
[CONTSEL-bit =[0]*]
YOUT = (CONT / 128) x ( YIN - 128) +128
Sub Address: 0x12 [7:0]
CONT0
~
CONT7
[CONTSEL-bit =[1]*]
YOUT = (CONT / 128) X YIN
YOUT: Contrast obtained by the calculation
YIN: Contrast before the calculation
CONT: Contrast gain factor (register setting value)
The gain factor can be set in the range {0~ (255 / 128)} in 1/128 step.
Default setting value is 0x80.
As the register setting shown in the above table, contrast adjustment inclination can be selected between 50%
and 0%.
Setting for contrast adjustment inclination
Register
CONTSEL
Definition
[0]: 50%
[1]: 0%
Sub Address: 0x0D [7]
[7.29.2] Brightness adjustment
Setting for brightness adjustment
Name
Definition
YOUT = YIN + BR
BR0
~
BR7
YOUT: Brightness obtained by the calculation
YIN: Brightness before the calculation
BR: Brightness gain factor (register setting value)
The gain factor can be set in the range {-128 ~ 126} in 1 step.
The setting is in 2’s complement.
Sub Address: 0x13 [7:0]
Settings for brightness and contrast adjustment status (ON/OFF) during VBI
Register
Status during VBI
VBIIMGCTL
[0]: Disable
[1]: Enable
Sub Address: 0x14 [7]
MS1230-E-00
- 54 -
2010/9