[XviD-devel] Global Motion Compensation

[Marco Al]

Christoph Lampert wrote:

>> Since you talked with him ... why does he in the "Real Time ..." paper only
>> use the robust estimator for finding an estimate for the translation and not
>> the other parameters of the affine transform? He does do so in his thesis for
>> finding global motion from the MPEG-2 motion vectors, but he does not refine
>> them afterwards for some reason ... he must have considered it, estimating
>> all parameters before gradient descent search, but Id still like to know the
>> reasons why it was not a good idea :)
>
> He uses the coefficients from previous frame as start values. Maybe
> those were simply superior to the poor estimates from block motion
> vectors...

AFAICS he only does that if there are minor changes in global motion, otherwise
he starts from the pure translational estimate.

Marco