Fast subpel motion estimation using selective motion vector accuracy of inter-mode decision for H.264/AVC

MPEG-4 Part-10 AVC/H.264 (H.264/AVC) is the newest video coding standard developed and finalized in March 2003 by the Joint Video Team (JVT) of ISO/IEC (MPEG) and ITU-T (VCEG). It includes many powerful features such as multiple reference pictures, variable block-size motion compensation, quarter-pel accuracy motion compensation, and so on. As a result, it achieves high coding performance but at the expense of huge computational complexity. To reduce the complexity while keeping the same coding performance, we propose a low complexity subpel motion estimation method using two content-aware decision criteria. Based on the criteria, four different levels of subpel motion estimation are proposed to achieve low complexity subpel motion estimation. Simulation results show that the proposed method reduces total encoding time by 55.53% on average and subpel motion estimation time by 82.2% on average.