H.261 Datasheet, PDF (22/31 Pages) List of Unclassifed Manufacturers – LINE TRANSMISSION OF NON-TELEPHONE SIGNALS

Run is a 6 bit fixed length code
Run
Code
0
0000 00
1
0000 01
2
0000 10
ξ
ξ
ξ
ξ
63
1111 11
Level is an 8 bit fixed length code
Level
−128
−127
ξ
00−2
00−1
0000
0001
0002
ξ
0127
Code
FORBIDDEN
1000 0001
ξ
1111 1110
1111 1111
FORBIDDEN
0000 0001
0000 0010
ξ
0111 1111
For all coefficients other than the INTRA dc one, the reconstruction levels (REC) are in the range −2048 to 2047 and are
given by clipping the results of the following formuls:
U REC = QUANT • (2 • level + 1); level > 0
VW _{REC = QUANT • (2 • level − 1); level < 0} ^{QUANT = “odd”}
U REC = QUANT • (2 • level + 1) − 1; level > 0
VW _{REC = QUANT • (2 • level − 1) + 1; level < 0} ^{QUANT = “even”}
REC = 0; level = 0
NOTE – QUANT ranges from 1 to 31 and is transmitted by either GQUANT or MQUANT.
Recommendation H.261 (03/93)
19