Fast Intra-picture Partitioning for Versatile Video Coding

A quadtree with nested multi-type tree structure has been integrated into the latest versatile video coding (VVC) pursuing a higher efficiency for more flexible representation in video content. But the great complexity would also cause a bottleneck for VVC all-intra application, where the encoder computes rate-distortion (RD) costs of all possible block modes to decide the optimum mode. To address this issue, an efficient and fast CTU partitioning scheme is proposed to skip the partial unnecessary block modes and some coding tools. Here the prediction models for rate and distortion are logically constructed by using contextual information, respectively. Then RD costs of the block modes are calculated and compared to determine whether to terminate block splitting. Experimental results demonstrate that a reduction about 20% in encoding time can be observed with negligible degradation in RD performance.