[M4IF Technotes] question about chroma interpolation

[Gaurav Aggarwal]

Hi all,
Pardon me if this is a stupid question:
Can somebody help me understand chroma interpolation, in specific how
to interpret Tables 7-6 to 7-9. We are trying to implement Simple Profile
so no quarter-pel. Only half-pel so we need only Table 7-8 and 7-9.
Table 7-8 -- Modification of eighth sample resolution chrominance
             vector components
eighth pixel position   0  1  2  3  4  5  6  7   //8
resulting position      0  0  1  1  1  1  1  2   //2
We have 4 luma vectors where each is half-pel. We add them and get a sum
that is again a max of half-pel resolution. What should we do with this
sum? Should we first divide by 8 (leading to 16th resolution) and then
use the table?
What is the meaning of the last column, e.g., //8 and //2 in the
above table? Can somebody help me with an example for say the sum of
4 luma vectors = 7, and say 8 and say 14 (where each is half-pel).
Half-pel Chroma will be 2, 2 and 3. Thus the eventual full-pel chroma
used for prediction will be 1, 1, and 1, right?
Thanks a lot!
Gaurav
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