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6245c7612a
The VC-1 mc prediction for combined horizontal and vertical offset
involves first a vertical 4-tap filter, followed by shifting,
followed by a horizontal 4-tap filter, followed by shifting by 7.
Both passes involve negative coefficients and therefore the
intermediate values for the >> 7 can exceed the range of
0..255*128 a bit in both directions. Therefore one can not simply
use either a logical or an arithmetic right shift. But one can use
them after having added a certain bias to ensure that one is in
the proper range. This is what this commit does.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
(cherry picked from commit 0056dd32fd)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>