Fast bottom-up pruning for HEVC intraframe coding

In intraframe coding of the High Efficiency Video Coding (HEVC) standard, up to 35 modes are defined for intra prediction and the quadtree structure is used for adaptive block partition. While such flexibility leads to more efficient compression, it also dramatically increases the encoder complexity. In this paper, a simple yet effective fast bottom-up pruning algorithm is proposed to reduce the computational cost. Mode decision at a large coding unit (CU) is selectively skipped based on the block structures of its sub-CUs. Our experimental results show that the proposed scheme can effectively reduce the encoder complexity without compromising the compression efficiency.