Fast coding unit partitioning algorithms for versatile video coding intra coding

Versatile video coding (VVC) is the newest video compression standard. It adopts quadtree with nested multi-type tree (QT-MTT) to encode square or rectangular coding units (CUs). The QT-MTT coding structure is more flexible for encoding video texture, but it is also accompanied by many time-consuming algorithms. So, this work proposes fast algorithms to determine horizontal or vertical split for binary or ternary partition of a 32 × 32 CU in the VVC intra coding to replace the rate-distortion optimization (RDO) process, which is time-consuming. The proposed fast algorithms are actually a two-step algorithm, including feature analysis method and deep learning method. The feature analysis method is based on variances of pixels, and the deep learning method applies the convolution neural networks (CNNs) for classification. Experimental results show that the proposed method can reduce encoding time by 28.94% on average but increase Bjontegaard delta bit rate (BDBR) by about 0.83%.