Priority classification based fast intra mode decision for High Efficiency Video Coding

The latest High-Efficiency Video Coding (HEVC) video coding standard version 1 offers 50% bit rate reduction against the H.264/AVC at the same visual quality. However, HEVC encoder complexity is tremendously increased. It is therefore important to develop efficient encoding algorithms for the success of HEVC based applications. In this paper, we propose a priority classification based fast intra mode decision to speed up the HEVC intra encoder. Each prediction unit (PU) is given a priority label out of four based on its spatial and temporal neighbor PU information as well as the predicted PU depth. Different processing strategy will be applied to different priority class, under the assumption that more computing resource should be allocated to the high priority class since its corresponding PU has the high potential to be chosen as the optima. Experiments are performed using all the common test sequences, and results show that, the encoder complexity is significantly reduced by about 46% for All Intra configuration with BD-Rate (Bjontegaard Delta Rate) increase less than 0.9% for luma component. Meanwhile, compared with several recent works, our proposed solution demonstrates the well trade-off between the coding efficiency and complexity reduction.