In one implementation, it is determined which {HEAD ~ motion vector syntax elements} have {TAIL ~ at least two alternative syntax values} satisfying Requirements R1 and R2, such that use of one of the alternative syntax values will yield a reconstructed block with higher mean luminance and use of a different alternative syntax value will yield a reconstructed block with lower mean luminance 
In one implementation , it is determined which { HEAD ~ motion vector syntax elements } have { TAIL ~ at least two alternative syntax values } satisfying Requirements R1 and R2 , such that use of one of the alternative syntax values will yield a reconstructed block with higher mean luminance and use of a different alternative syntax value will yield a reconstructed block with lower mean luminance
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH