Exploration of motion estimation algorithm in graphics processing environment

• Ronaldo Husemann UFRGS
• Augusto Lenz UNIVATES
• Marco Antonio Gobbi UNIVATES
• Valter Roesler UFRGS
• José Valdeni de Lima UFRGS

Resumo

Currently, even considering the recent advances in the microprocessor power computing, high definition multimedia applications still require very complex demands to allow real-time video encoding. Particularly, modern video encoders (MPEG/ITU H.26x series) depend of complex and computationally exhaustive motion estimation algorithms to identify and remove temporal redundancy among consecutive (or not) frames inside a video sequence, as strategy to reduce the final compressed bit rate. In fact, the mechanism of block matching can be considered the most critical encoder algorithm, in terms of computational demands, like it is responsible for searching, in distinct reference frames, for similar pixel blocks related with each one of the input image blocks. The number of required block comparisons for high definition videos represents a clear and important restriction for real-time implementations. This paper introduces an improved strategy of block matching method, which was optimized for multiprocessing execution, mainly focusing in implementation over general purpose graphical processing unit technologies, as the NVidia CUDA® GPUs. The improved motion estimation solution was implemented in the JSVM reference code (scalable version of H.264 video encoder), when it was registered a speed up gain of more than 350% in average for 4CIF videos.