refIdxL0 = MinPositive( refIdxL0A, MinPositive(refldxL0B, refIdxL0C)) (8-184) refIdxL1 = MinPositive( refIdxL1A, MinPositive(refldxL1B, refIdxL1C)) (8-185) directZeroPredictionFlag = 0 (8-186) where ) if x >=0 and otherwise (8-187) 5. When both reference indices refIdxL0 and refldxL 1 are less than 0, refIdxL0 = 0 (8-188) refIdxL1 = 0 (8-189) directZeroPredictionFlag= 1 (8-190) Rec. ITU-T H.264 (01/2012) The process specified in clause 8.4.1.2.1 is invoked with mbPartIdx, subMbPartIdx given as input and the output is assigned to refldxCol and myCol. The variable colZeroFlag is derived as follows: If all of the following conditions are true, colZeroFlag is set equal to 1: RefPicList1| is currently marked as "used for short-term reference", refldxCol is equal to 0, both motion vector components mvCol[ 0 ] and mvCol[ 1] lie in the range of -1 to 1 in units specified as follows: If the co-located macroblock is a frame macroblock, the units of mvCol[ 0] and mvCol[ are units of quarter luma frame samples. Otherwise (the co-located macroblock is a field macroblock), the units of mvCol[ and mvCol[ 1 ] are units of quarter luma field samples. NOTE 2 - For purposes of determining the condition above, the value mvCol[ 1 ] is not scaled to use the units of a motion vector for the current macroblock in cases when the current macroblock is a frame macroblock and the co-located macroblock is a field macroblock or when the current macroblock is a field macroblock and the co-located macroblock is a frame macroblock. This aspect differs from the use of mvCol[ 1 ] in the temporal direct mode as specified in clause 8.4.1.2.3, which applies scaling to the motion vector of the co-located macroblock to use the same units as the units of a motion vector for the current macroblock, using Equation 8-193 or Equation 8-194 in these cases. Otherwise, colZeroFlag is set equal to 0. The motion vectors mvLX (with X being 0 or 1) are derived as follows: If any of the following conditions are true, both components of the motion vector mvLX are se