urrent picture CurrPic. Otherwise (vertMvScale is equal to Fld_To_Frm), MapColToList0( refIdxCol ) returns the lowest valued reference index refIdxL0 in the current reference picture list RefPicList0 that references the frame or complementary field pair that contains refPicCol. RefPicList0 shall contain a frame or complementary field pair that contains the field refPicCol. NOTE 2 - A decoded reference picture that was marked as "used for short-term reference" when it was referenced in the decoding process of the picture containing the co-located macroblock may have been modified to be marked as "used for long-term reference" before being used for reference for inter prediction using the direct prediction mode for the current macroblock. Depending on the value of vertMvScale the vertical component of mvCol is modified as follows: If vertMvScale is equal to Frm_To_Fld mvCol[ = mvCol[ ] ] / 2 (8-193) Otherwise, if vertMvScale is equal to Fld_To_Frm mvCol[1]=mvCol[1]*2 (8-194) Otherwise (vertMvScale is equal to One_To_One), mvCol[ 1 ] remains unchanged. The variables currPicOrField, pic0, and picl, are derived as follows: Rec. ITU-T H.264 (01/2012) If field_pic_flag is equal to 0 and the current macroblock is a field macroblock, the following applies: currPicOrField is the field of the current picture CurrPic that has the same parity as the current macroblock. 2. picl is the field of RefPicList1[ 0] that has the same parity as the current macroblock. 3. The variable pic0 is derived as follows: If refIdxL0 % 2 is equal to 0, pic0 is the field of RefPicList0[ refIdxL0/21 that has the same parity as the current macroblock. Otherwise (refldxL0 % 2 is not equal to 0), pic0 is the field of RefPicList0[ refIdxL0/ that has the opposite parity of the current macroblock. Otherwise (field_pic_flag is equal to 1 or the current macroblock is a frame macroblock), currPicOrField is the current picture CurrPic, picl is the decoded reference picture RefPicList1 0], and pic0 is the decoded reference picture RefPicList0[refIdxLO ]. The