Optimized implementation of motion compensation for H.264 decoder

Predictive coding is widely used in video codec standards, especially for applications requiring low bit-rate coding like video broadcasting, video streaming and video conferencing. Motion compensation is used as a part of the predictive coding to provide a prediction for the macroblock. Considering that the motion compensation in H.264/AVC takes about one-fourth of the decoding time, in this paper we propose an optimized implementation of motion compensation algorithm. The proposed implementation uses the macroblock (MB) mode of decoded macroblocks to improve performance degradation in data manipulation and single-instruction, multiple data (SIMD) to simplify linear interpolation. Experimental results show that this implementation significantly improves timing performance of motion compensation and the speed of overall decoder without loss in video quality. The results of implementation on a general purpose DSP are compared with other recent optimization techniques showing the efficacy of proposed technique.