Improved Sorting Algorithm for Explicit FMO Macroblock Classification in H.264

An improved sorting algorithm is presented that classifies macroblocks into different slice groups for FMO in H.264. The classification process reinforces the slice structured coding nature of H.264 by making a conscious effort to minimize the variations in the statistics of the macroblock parameters of the resulting slice group maps. Results show that modest improvements can be achieved in terms of PSNR and the number of undecodable macroblocks by using the proposed improved sorting algorithm as compared to an interleave sorting algorithm where the MB is assigned to different slice groups following the order of the sorted list.