An efficient video transcoding algorithm from h.264 to hevc

Abstract

Video transcoding method usually reduces coding complexity with the cost of reducing coding efficiency. It is necessary to design a video transcoder can achieve a better trade-off between coding efficiency and complexity. This paper proposes an efficient video transcoder based on improved rate distortion optimization and improved motion vector (MV) reuse. First, we use an improved temporal dependent rate distortion optimization method to implement rate-distortion optimization (RDO) at the level of Coding Tree Units (CTUs). Second, we use improved motion vector reuse (IMVR) to reduce the complexity of encoding. Experimental results have shown that the proposed method can achieve an average reduction of 38.4% in the transcoding time with the cost of 0.6% BDBR increase compared with HEVC Test Model (HM) 16.9 encoder. It verifies that the proposed method can achieve a better trade-off between coding efficiency and complexity compared with existing transcoding methods.