An LSTM Method for Predicting CU Splitting in H.264 to HEVC Transcoding

For H.264 to high efficiency video coding (HEVC) transcoding, this paper proposes a hierarchical Long Short-Term Memory (LSTM) method to predict coding unit (CU) splitting. Specifically, we first analyze the correlation between CU splitting patterns and H.264 features. Upon our analysis, we further propose a hierarchical LSTM architecture for predicting CU splitting of HEVC, with regard to the explored H.264 features. The features of H.264, including residual, macroblock (MB) partition and bit allocation, are employed as the input to our LSTM method. Experimental results demonstrate that the proposed method outperforms the state-of-the-art H.264 to HEVC transcoding methods, in terms of both complexity reduction and PSNR performance.