Digital Signal Processing Reference
In-Depth Information
80
Message of Description 1
60
40
20
0
12
34567
Message no.
8
9
10
11
12
13
80
Message of Description 2
60
40
20
0
123456789 0 1 2 3
Message no.
Fig. 4.46
Messages of each description
Tabl e 4. 6
The code structure of each
description for “Coastguard.qcif”
Message no.
Frame amounts
Coding structure
1
34
I-P-B-B- P-B-B :::
2
1
I
3
1
I
4
3
I-P-B
5
2
I-P
6
1
I
7
1
I
8
1
I
9
1
I
10
1
I
11
34
I-P-B-B- P-B-B :::
12
4
I-P-B-B
13
75
I-P-B-P-B :::
According to the frame amounts of messages in Fig.
4.46
, the coding structure
for each description, that is, the coding type for each frame, is designed, as shown
in Table
4.6
.Table
4.6
, shows the flexible GOP to satisfy the different messages.
Furthermore, the frames with high motion are encoded as
I
frame, which may be
assigned for important protection using PET algorithm.
