Fast macroblock mode selection in H.264/AVC

Abstract

Original flow of macroblock mode selection in H.264/AVC involves searching over all the possible modes (Skip/Direct, 7 Inter and 3 Intra modes) and the process requires fast machines to achieve real time encoding. Findings of research papers indicate there are close relationships between current encoding block and neighbouring blocks and the accuracy using previously encoded frames to predict the best mode of current encoding block is high in low motion video sequences. For the above reasons, Fast Macroblock Mode Selection (FMMS) algorithm based on motion correlation and motion history is introduced in this project to reduce encoding complexity in the H.264/AVC encoder and hence shorten the encoding time to increase the ability of real time encoding in machines of slower processing power. The algorithm was implemented using open source H.264/AVC reference software JM10.1 and the simulation results show that encoding time of first 100 frames of various video sequences can be reduced up to 40 to 60 per cent using the new algorithm without significant increase in bit-rate and reduction in video quality. To test the JM encoded videos, we make use of an existing cross-platform video player, MPlayer. Unfortunately, some header information is missing in JM encoded videos and MPlayer is unable to play those videos without manually setting the original playback parameters. To solve this bug, I have developed a new GUI interface for MPlayer and JM encoded videos can be played directly using the new MPlayer GUI interface. By finishing the two objectives in this project, H.264 encoded video playback can be more convenient and the encoding time can also be reduced significantly without much loss in video quality.