H.261 Datasheet, PDF (24/31 Pages) List of Unclassifed Manufacturers – LINE TRANSMISSION OF NON-TELEPHONE SIGNALS

TABLE 6/H.261
Reconstruction levels for INTRA-mode dc coefficient
FLC
Reconstruction level into
inverse transform
0000 0001 (1)
0000 0010 (2)
0000 0011 (3)
ξ
ξ
0111 1111 (127)
1111 1111 (255)
1000 0001 (129)
ξ
ξ
1111 1101 (253)
1111 1110 (254)
0008
0016
0024
ξ
ξ
1016
1024
1032
ξ
ξ
2024
2032
NOTE – The decoded value corresponding to FLC “n” is 8n except FLC 255 gives 1024.
4.3.3 Freeze picture release
A signal from an encoder which has responded to a fast update request and allows a decoder to exit from its freeze picture
mode and display decoded pictures in the normal manner. This signal is transmitted by bit 3 of PTYPE (see 4.2.1) in the
picture header of the first picture coded in response to the fast update request.
5
Transmission coder
5.1 Bit rate
The transmission clock is provided externally (for example from an I.420 interface).
5.2 Video data buffering
The encoder must control its output bitstream to comply with the requirements of the hypothetical reference decoder defined
in Annex B.
When operating with CIF the number of bits created by coding any single picture must not exceed 256 Kbits. K=1024.
When operating with QCIF the number of bits created by coding any single picture must not exceed 64 Kbits.
In both the above cases the bit count includes the picture start code and all other data related to that picture including
PSPARE, GSPARE and MBA stuffing. The bit count does not include error correction framing bits, fill indicator (Fi), fill
bits or error correction parity information described in 5.4.
Video data must be provided on every valid clock cycle. This can be ensured by the use of either the fill bit indicator (Fi) and
subsequent fill all 1's bits in the error corrector block framing (see Figure 13) or MBA stuffing (see 4.2.3) or both.
Recommendation H.261 (03/93)
21