A novel fast inter mode decision in H.264/AVC based on a regionalized hypothesis testing

The H.264/AVC standard achieves a high coding efficiency compared to previous standards, but in exchange for a very high computational cost. This paper focuses on the mode decision subsystem, which is a critical one from the computational cost point of view. In particular, a hierarchical early-termination-based approach to the inter mode decision problem is proposed, in such a way that a cascade of early stops are considered, going from the most likely modes to the less likely ones. The main novelty of the proposed algorithm relies on the use of a regionalized hypothesis testing methodology for making the decisions on every potential early stop. The proposed method has been assessed on a large set of QCIF video sequences for several qualities, achieving a quite notable improvement in terms of total encoding time reduction in relation to a well-established mode decision method. Specifically, the time reduction is 43.43 % and 21.33 % for IPPP and IBBP patterns, respectively, without any significant quality loss.