Fast selective algorithm of Intra prediction for H. 264/AVC

The newest video coding standard H.264/AVC provides several predicting modes and directions for Intra prediction in the spatial region, and the optimal mode was selected by rate-distortion optimization (RDO) with high coding complexity. In order to solve this problem, the fast selection algorithm was proposed from different aspects; Firstly, for luminance mode selection, the method was proposed that utilizes the image entropy value to predict the mode of the macroblock, and updates the threshold adaptively by a sliding window. Secondly, intermediate computing results were reused to reduce the predicting directions. Finally, in the RDO performance, the arithmetic structure of Intra prediction was changed with calculating the best chro-mance mode separately. Experimental results show that with similar distortion performance, the algorithm that adopt the above three strategy can efficiently reduce the computational complexity up to 76% with 2.6% increase of bits rate averagely.