[x264-devel] x264_me_search_ref

[Johannes Ballé]

Hi,

I've got a few requests regarding x264_me_search_ref in me.c.

line 179) Why are p_cost_mv{x,y} adjusted for a clipped mvp? As far as I know, 
clipping of the predictor is not done in the decoder, so unless there is some 
special magic involved, shouldn't this yield the wrong cost measure? The 
comment doesn't really make sense to me, because it's not mvp that's clamped 
here, only the cost measure is moved.

lines 209 and 515) I don't understand either why the mv cost is subtracted in 
line 209 nor why it is added in line 515. Could this be related? In line 209, 
it obviously wasn't clear to the author himself. In line 515, m->cost should 
already include mv_cost (because of the way COST_MV_* works), so I don't see 
a reason why it is added there again.

lines 222ff) Why is it necessary to adjust the limits like that? Shouldn't 
h->mb.mv_min_fpel etc. already contain the correct limits?

I did some minor cleanup of the code (see attached file). It's not tested and 
only meant to clarify what I'm trying to say. If you would, please 
double-check and give comments.

Thanks,

-- 
Johannes Ballé
RWTH Aachen University
johannes.balle at rwth-aachen.de
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