Game Development Reference
In-Depth Information
Table 9.1
Coding
performance and complexity
reduction of the proposed fast
intracoding scheme
Sequence
BD-rate (%)
ʔ
T
(%)
ClassA
0.80
32.00
ClassB
0.60
30.10
ClassC
0.60
18.40
ClassD
0.60
19.50
ClassE
1.20
35.50
Average
0.70
25.10
In this equation, Th
1
,Th
2
and Th
3
are the thresholds, which can be updated adaptively
according to the previous coded frames,
N
j
1
2
i
−
1
·
1
N
j
Va r
Pre
r
Th
i
=
(9.7)
r
=
1
In this equation,
N
j
denotes the number of the prediction units with the partition
depth as denoted by
j
in the previous frame, and Var
Pre
r
is the corresponding gradient
variance.
In order to verify the proposed optimization scheme, experiments are conducted
on the reference software RD6.0. The results are illustrated in the Table
9.1
. It can
be observed that the proposed scheme can save the coding complexity by 25.1% on
average with negligible performance loss.
9.1.2 Hierarchical Coding Structure
In this section, we will present the hierarchical coding structure of AVS2 based on the
flexible reference picture management scheme. It is noted that the reference picture
management scheme is a normative coding that provides the flexibility of construct-
ing the reference pictures. Through the information in the reference configuration
set (RCS), the encoder can arbitrarily configure the reference picture set for current
coding picture.
9.1.2.1 Reference Configuration Set
RCS consists of reference picture information of current coding picture including
the coding order index (COI), playing order index (POI), QP offset, the number of
reference pictures, delta COI between current picture and reference picture, number
of pictures that need to remove from buffer and delta COI between pictures from
buffer and current picture.
The COI is used to represent the coding order of current picture and reference pic-
tures. And POI is used to represent the playing order of current picture and reference
