Graphics Reference
In-Depth Information
Fig. 7.7
Decisions for each
four-sample segment of block
boundary.
PU
prediction unit,
TU
transform unit [
37
]
Boundary is
aligned with 8x8
sample grid?
No
Boundary is
between PU
or TU?
No
Boundary
strength
Bs > 0?
No
Condition (7.1) true?
No
Conditions
(7.2), (7.3), (7.4)
true?
No filtering
Yes
No
Strong filtering
Normal filtering
crossing the block boundary. Since condition in (
7.1
) is evaluated true for the signal
that forms a perfect ramp passing across the block boundary (such as a gradual
change in the luma component), the deblocking in the normal filtering mode is
designed to not modify the ramp. The filtered sample values
p
0
0
and
q
0
0
(the row
index
j
is omitted for brevity) are determined by adding or subtracting an offset
value
4
0
to each of the sample values:
p
0
0
D
p
0
C
0
;
(7.7)
q
0
0
D
q
0
0
;
(7.8)
wherethevalueof
4
0
is obtained as in
0
D
Clip3.-t
C
;t
C
;•/;
(7.9)