A Fast Pu Mode Decision Algorithm for H.264/avc to Hevc Transcoding

H.264/AVC has been widely applied to various applications. However, a new video compression standard, High Efficient Video Coding (HEVC), had been finalized recently. In this work, a fast transcoder from H.264/AVC to HEVC is proposed. The proposed algorithm includes the fast prediction unit (PU) decision and the fast motion estimation. With the strong relation between H.264/AVC and HEVC, the motion vectors (MVs), residuals, and modes from each coding block of H.264/AVC can be reused to predict the current encoding PU of HEVC. Furthermore, the MV variance from H.264/AVC is calculated to decide the search range of PU and also to reduce the prediction mode. Simulation results show that the proposed method can save up to 53% of the encoding time and maintains the rate-distortion (R-D) performance for HEVC.