Graphics Reference
In-Depth Information
Sum of Square Error
.
SSE
/
D
X
i;j
.s
A
.i; j /
s
B
.i; j //
2
(9.4)
Sum of Absolute Difference
D
X
i;j
j
s
A
.i; j /
s
B
.i; j /
j
(9.5)
Hadamard Transformed SAD
.
SATD
/
D
X
i;j
j
HT
.i; j /
j
(9.6)
HT
(
i
,
j
)in(
9.6
)isthe(
i
,
j
)
th
coefficient of a block that is obtained by applying
Hadamard transform to the block difference between blocks A and B.
JCT-VC [
15
] specifies also the following œ values:
œ
mode
D
˛
W
k
2
..
QP 12
/
=3:0
/
(9.7)
œ
pred
D
p
œ
mode
(9.8)
¨
chroma
D
2
..QP QP
chroma
/=3:0/
(9.9)
˛
D
1.0
Clip
3(0.0, 0.5, 0.05 *
number
_
of
_
B
_
frames
) for referenced pictures
˛
D
1:0
for non-referenced pictures
(9.10)
where
<
x
I
z
<x
y
I
z
>y
z
I
otherwise
Clip
3.x;y;
z
/
D
:
Interested readers are referred to [
15
] for derivation of
W
k
as well as œ values for
chroma.
CU level mode decision (intra vs. inter) coding is based on finding coding
parameters that minimize cost function
J
mode
in (
9.11
).
J
mode
D
.S SE
l
u
ma
C
!
chroma
SSE
chroma
/
C
mode
R
mode
(9.11)
Distortion terms
SSE
luma
and
SSE
chroma
correspond to the SSE between the
original and reconstructed luma and chroma CU blocks respectively. Similarly,
R
mode
represents the total number of bits used for CU level intra or inter mode
signaling, PU partition(s) within the CU, PU prediction mode(s) in case of intra
mode or PU motion parameters in case of inter mode, TU quadtree partition(s),
and finally number of bits required for representing quantized residual transform
coefficient levels.
For finding the best inter CU coding cost,
J
mode
is evaluated for all possible PU
partition modes (e.g., 2N
2N, N
N, 2N
N, N
2N, nl
2N, nR
2N) and a
partition that gives the minimum coding cost is chosen.
