[M4IF Technotes] h.263 motion vector predictor

[Christoph Lampert]

On Wed, 21 May 2003, Ariel David wrote:
> 
> are predictors that are skipped macroblock computed differently or are
> they considered 0,0 motion vector. For example: if the top left MV is
> 0,0, the top MV is 1,1 and the left is skipped will the predictor be
> 0,0 (regular median) or 1,1 (since the left is not considered).

"skip" is (0,0). The only cases where MVs are "not considered" is in the
top row, then predictor is simply the left neighbour's MV. Otherwise, it's 
always median where missing vectors (intra-blocks, skip-blocks, leftmost
column) are treated as (0,0).
Btw. it's median of LEFT, TOP and TOP-RIGHT, _not_ TOP-LEFT! 
Christoph