Quote:
Originally Posted by Stux
1) The motion vectors generally double in size as the enhanced precision means that you need enhanced precision motion vectors! And that can often lead to a loss in overall coding efficiency
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Double in size?
Going from hpel to qpel is one single bit of motion vector for each direction, X and Y.
So, for example, lets say we have a motion vector (6.5,8.5). This takes a total of 10 bits (ignoring entropy encoding, etc). The qpel version might be (6.5, 8.75). This would be 11 bits.