runs of zero transform coefficient levels before each non-zero transform coefficient level are derived by parsing total_zeros and un_before as specified in clause G.9.2.2. The level and run information are combined into the list coeffLevel as specified in clause 9.2.4. G.9.2.1 Additional parsing process for total number of non-zero transform coefficient levels and number of trailing ones Inputs to this process are variables nC, totalCoeffStart, and trailingOnesStart. Outputs of this process are variables totalCoeff and trailingOnes. Let invTotalCoeff( coeffTokenIdx ) and invTrailingOnes( coeffTokenIdx) be functions that map the variable coeffTokenIdx to the variables nX and nY, respectively, as specified in Table G-10 for each value of the variable nC. A variable dX is set equal to (scan_idx_end-scan_idx_start+2). - A variable dY is set equal to Min( 4, scan_idx_end - scan_idx_start+2). A variable targetCoeffTokenIdx is derived as specified by Table G-10 given the variables nC, nX = totalCoeffStart, and nY = trailingOnesStart. The bitstream shall not contain data that result in a value of targetCoeffTokenIdx that exceeds the range of values from 0 to ( dX * dY - Min( ( dY -1)))), inclusive. A variable coeffTokenIdx is derived as specified by the following pseudo code: for( coeffTokenIdx = 0,i=0; <= targetCoeffTokenIdx; coeffTokenIdx++) invTotalCoeff( coeffTokenIdx ) < dX && invTrailingOnes( coeffTokenIdx ) dY) (G-359) The variable totalCoeff is set equal to invTotalCoeff( coeffTokenIdx -1) and the variable trailingOnes is set equal to invTrailingOnes( coeffTokenIdx - 1). When the CAVLC parsing process is invoked for Intra16x16ACLevel, CbIntra16x16ACLevel, CrIntra16x16ACLevel, or ChromaACLevel, it is a requirement of bitstream conformance that the bitstream shall not contain data that result in totalCoeff being greater than (scan_idx_end - Max( 1, scan_idx_start) Table G-10 - Mapping of ( nX, nY) to coeffTokenIdx and vice versa 0<=nC<2 4<=nC<8 Rec. ITU-T H.264 (01/2012) Table G-10 - Mapping of ( nX, nY) to coeffTo