[x264-devel] Question on the motion vector resultion

[Erich Marth]

Hi there

I do have a question. I'm doing some research on the motion estimation  
algorithm.
For each slice, every single macroblock is analyzed.
Based on the SLICE_TYPE, the analyzing is done on intra or inter  
decisions.

In the P/B slice case
we do first calc the cost for all valid mv cases.
in the x264_macroblock_analyze method we try to find the best match.
But first we are going to predicted the needed motion vector from  
available neighbours.
In H.264 the motion vector's resolution is able to do quarter pel  
positions.
But the mvp which is calculated in the mv fetch  
(x264_mb_predict_mv_16x16) method is of type integer?
Why? I mean if all neighboring macroblocks do have quarter pel positions
the current mvp shall be on a quarter pel position too? So why integer?

And why didn't I find any half/quarter pel estimation in diamond  
search ... ?

thanks a lot
erich