H.261
| Model | H.261 |
| Description | LINE TRANSMISSION OF NON-TELEPHONE SIGNALS |
| PDF file | Total 31 pages (File size: 126K) |
| Chip Manufacturer | ETC |
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T r a ns fo rm
Q ua n ti z er
P i c tu r e m e m or y wi th m o ti o n c om p en s a te d v ar i ab l e de l ay
L o op f il te r
C o d in g c o nt ro l
F l a g fo r IN T R A /IN T E R
F l a g fo r tr a n s m i tte d o r n o t
Q ua n ti z er in d ic ati o n
Q ua n ti z i ng i n de x f or t ra n s fo rm c oe ff i c ie n ts
M o ti o n v ec t or
S w i tc h in g o n/ off o f t he l o op f i lte r
FI GURE 3/H.261
Source coder
FIGURE 3/H.261...[D03] = 16 CM
3.2.3
Loop filter
The prediction process may be modified by a two-dimensional spatial filter (FIL) which operates on pels within a predicted 8
by 8 block.
The filter is separable into one-dimensional horizontal and vertical functions. Both are non-recursive with coefficients of 1/4,
1/2, 1/4 except at block edges where one of the taps would fall outside the block. In such cases the 1-D filter is changed to
have coefficients of 0, 1, 0. Full arithmetic precision is retained with rounding to 8 bit integer values at the 2-D filter output.
Values whose fractional part is one half are rounded up.
Recommendation H.261
(03/93)
5
