UG-707
ADV8005 Hardware Reference Manual
MPEG1 systems (block size control). DNR can be applied to the resulting block transition areas that are known to contain noise. Generally, the
block transition area contains two pixels. It is possible to define this area to contain four pixels (border area).
It is also possible to compensate for variable block positioning or differences in YCrCb pixel timing with the use of the DNR block offset.
The digital noise reduction registers are three 8-bit registers. They are used to control the DNR processing.
To enable the SD DNR feature,
must be programmed.
dnr_en
, Encoder Map,
Address 0xE481[7]
This bit is used to enable the SD Digital Noise Reduction (DNR) function.
Function
dnr_en
Description
1
Enabled
0 (default)
Disabled
7.4.19.1.
Coring Gain Border
is the gain factor applied to border areas (refer to
for more information on border areas). In DNR mode, the
range of gain values is 0 to -1 in decrements of 1/8. This factor is applied to the DNR filter output that lies below the set threshold range. The
result is then subtracted from the original signal.
In DNR sharpness mode, the range of gain values is 0 to 0.5 in increments of 1/16. This factor is applied to the DNR filter output that lies above
the threshold range. The result is added to the original signal.
dnr_coring_gain_a[3:0]
, Encoder Map,
Address 0xE4A3[7:4]
This signal is used to configure the coring gain border (in Digital Noise Reduction (DNR) mode, the values in brackets apply).
Function
dnr_coring_gain_a[3:0]
Description
0000 (default)
No gain
0001
+1/16 [−1/8]
0010
+2/16 [−2/8]
0011
+3/16 [−3/8]
0100
+4/16 [−4/8]
0101
+5/16 [−5/8]
0110
+6/16 [−6/8]
0111
+7/16 [−7/8]
1000
+8/16 [−1]
7.4.19.2.
Coring Gain Data
is the gain factor applied to the luma data inside the MPEG pixel block. In DNR mode, the range of gain values is 0 to
-1 in decrements of 1/8. This factor is applied to the DNR filter output that lies below the set threshold range. The result is then subtracted from
the original signal.
In DNR sharpness mode, the range of gain values is 0 to 0.5 in increments of 1/16. This factor is applied to the DNR filter output that lies above
the threshold range. The result is added to the original signal.
explains the difference between SD DNR border gain and data gain.
Figure 128: SD DNR Offset Control
O X X X X X X O O X X X X X X O
O X X X X X X O O X X X X X X O
O X X X X X X O O X X X X X X O
DNR27 TO DNR24 = 0x01
OFFSET CAUSED
BY VARIATIONS IN
INPUT TIMING
APPLY BORDER
CORING GAIN
APPLY DATA
CORING GAIN
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