H.261 Datasheet, PDF (19/31 Pages) List of Unclassifed Manufacturers – LINE TRANSMISSION OF NON-TELEPHONE SIGNALS

TCOEFF
EOB
FIGURE 11/H.261
Structure of block layer
1
2
6
7 15 1 6 28 29
3
5
8 14 17 2 7 30 43
Incr eas ing cycles
pe r pict ure width
4
9 1 3 18 26 3 1 42 44
I ncreasin g cycles
10 12 1 9 25 32 4 1 45 54 _{p er picture he igh t}
11 20 2 4 33 40 4 6 53 55
21 23 3 4 39 47 5 2 56 61
22 35 3 8 48 51 5 7 60 62
36 37 4 9 50 58 5 9 63 64
T1 51 410 0-9 3/d07
FIGURE 12/H.261...[D07] = 6 CM
FIGURE 12/H.261
Transmission order for transform coefficients
Codes are given in Table 5.
The most commonly occurring combinations of zero-run and the following value are encoded with variable length codes as
listed in the table 5. End of block (EOB) is in this set. Because CBP indicates those blocks with no coefficient data, EOB
cannot occur as the first coefficient. Hence EOB can be removed from the VLC table for the first coefficient.
The last bit “s” denotes the sign of the level, “0” for positive and “1” for negative.
The remaining combinations of (run, level) are encoded with a 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
level. Use of this 20-bit word form encoding the combinations listed in the VLC table is not prohibited.
16
Recommendation H.261 (03/93)