Graphics Reference
In-Depth Information
All pictures
are IDR picture
…
I
0
I
1
I
2
I
3
I
4
I
5
I
6
I
7
I
8
time
Coding order
0
1
2
3
4
5
6
7
8
QP offset
0
0
0
0
0
0
0
0
0
Fig. 9.1
The prediction structure of the intra-only configuration
B
7
B
3
B
5
B
1
B
6
B
2
B
4
…
…
I
0
B
8
time
Coding order
QP offset
0
4
3
5
2
7
6
8
1
0
4
3
4
2
4
3
4
1
Fig. 9.2
The prediction structure of the random access configuration
9.2.3.3
Low-Delay P (LDP)
In this configuration, the first picture is encoded as an I picture and the subsequent
pictures are encoded as P pictures. Since reordering of pictures is not allowed and
only past pictures are used for prediction, the coding delay, in this configuration,
may be made small. Figure
9.3
shows an example of this prediction structure. QP
offset values are summarized for each picture in Fig.
9.3
.
9.2.3.4
Low-Delay B (LDB)
In this configuration, similar to the previous configuration, reordering of pictures
is not allowed. The first picture is encoded as an I picture and subsequent pictures
are encoded as B pictures. Moreover, since past B pictures are used for prediction,
a low coding delay, similar to LDP, but with higher coding efficiency (because of
bi-prediction) is achieved. QP offset values, for each picture, are summarized in
Fig.
9.3
.
