Fast‐efficient algorithm of high‐profile intra prediction for H.264 encoding system

This study presents a fast intra‐prediction algorithm for a high‐profile H.264 encoder. First, a pre‐decision algorithm is proposed to reject the impossible block size based on image variance. Then a fast 4 × 4 block prediction algorithm is proposed to select four possible modes from nine predicted modes based on the edge‐filtering detection. With a hierarchical approach, the 8 × 8 block prediction is based on the result of the chosen 4 × 4 block mode. This approach selects only one to five modes of H.264 coding from nine prediction modes. Following the prediction of the 16 × 16 luminance block and 8 × 8 chrominance block is mapped by the result of the 8 × 8 luminance block by checking only one to two modes. The pre‐decision algorithm, the fast 4 × 4, 8 × 8 and 16 × 16 block prediction algorithms can be combined to improve the coding speed. Simulations demonstrate that the proposed algorithm can save about 70% coding time at most for intra‐frame coding in the H.264 system while increasing only about 1% bit‐rate with a negligible peak signal‐to‐noise ratio drop.