Sd Brightness Detect; Sd Brightness Control - Analog Devices ADV8003 Hardware Manual

8.4.13. SD Brightness Detect

The ADV8003 encoder core allows the user to monitor the brightness level of the incoming video data. This feature is used to monitor the
average brightness of the incoming Y signal on a field-by-field basis. The information is read from the I
the color saturation, contrast, and brightness controls can be adjusted, for example, to compensate for very dark pictures.
The luma data is monitored in the active video area only. The average brightness I
every VSYNC signal. This can be monitored using bright_detect_val[7:0].
bright_detect_val[7:0], Encoder Map, Address 0xE4BA[7:0] (Read Only)
This register is used to adjust the SD brightness value. The higher the value, the higher the brightness level.
Function
bright_detect_val[7:0]
0x00 

8.4.14. SD Brightness Control

When this feature is enabled, the SD brightness/WSS control register, setup[6:0], is used to control brightness by adding a programmable
setup level onto the scaled Y data. To enable this feature,
setup_en, Encoder Map, Address 0xE487[3]
This bit is used to enable the SD brightness control feature.
Function
setup_en
1
0 
For NTSC with pedestal, the setup can vary from 0 IRE to 22.5 IRE. For NTSC without pedestal and for PAL, the setup can vary from −7.5
IRE to +15 IRE. Refer to Figure 112
The SD brightness control register is an 8-bit register. The seven LSBs of this 8-bit register are used to control the brightness level, which
can be a positive or negative value.
For example, to add a +20 IRE brightness level to an NTSC signal with pedestal, the procedure is as follows:
0 × (SD Brightness Value) =
0 × (IRE Value × 2.015631) =
0 × (20 × 2.015631) = 0 × (40.31262) ≈ 0x28
To add a –7 IRE brightness level to a PAL signal, write 0x72 to setup[6:0].
0 × (SD Brightness Value) =
0 × (IRE Value × 2.075631) =
0 × (7 × 2.015631) = 0x(14.109417) ≈ 0001110b
0001110b into twos complement = 1110010b = 0x72
setup[6:0], Encoder Map, Address 0xE4A1[6:0]
This signal is used to specify the SD brightness value.
Rev. B, August 2013
Description
Brightness value
setup_en
Description
Enabled
Disabled
for more details.
2 C register is updated on the falling edge of
must be configured.
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ADV8003 Hardware Manual
C and, based on this information,
2