H.261
| Model | H.261 |
| Description | LINE TRANSMISSION OF NON-TELEPHONE SIGNALS |
| PDF file | Total 31 pages (File size: 126K) |
| Chip Manufacturer | ETC |
P SC
TR
PT YPE
PE I
P S P A RE
P EI
G O B data
T1 5142 30- 93/ d0 5
FIGURE 5/H.261
Structure of picture layer
FIGURE 5/H.261...[D05] = 3 CM
4.2.2
Group of blocks layer
Each picture is divided into groups of blocks (GOBs). A group of blocks (GOB) comprises one twelfth of the CIF or one
third of the QCIF picture areas (see Figure 6). A GOB relates to 176 pels by 48 lines of Y and the spatially corresponding 88
pels by 24 lines of each of C
B
and C
R
.
Data for each group of blocks consists of a GOB header followed by data for macroblocks. The structure is shown in Figure
7. Each GOB header is transmitted once between picture start codes in the CIF or QCIF sequence numbered in Figure 6, even
if no macroblock data is present in that GOB.
1
3
5
7
9
11
CIF
2
4
6
8
10
12
1
3
5
QCIF
FIGURE 6/H.261
Arrangement of GOBs in a picture
Recommendation H.261
(03/93)
9
