Fast VVC intra prediction mode decision based on block shapes

Machine Learning-Based Early Skip Decision for Intra Subpartition Prediction in VVC

“…Since intra prediction can exploit closer reconstructed samples in previous subpartitions, significant accuracy improvement is expected in predictor generation [14]. In this regard, the authors in [19] proposed an ISP-PPC scheme (ISP with prepruned candidates), which adds an intra prediction mode to the HOR-ISPList (intra mode candidate list for HOR-ISP) or VER-ISPList (intra mode candidate list for VER-ISP) only when the mode can utilize closer reconstructed samples in consideration of the directions of split and prediction.…”

“…Even after the much enhanced ISP encoder search solution was implemented, however, efforts to minimize ISP complexity while maintaining ISP coding efficiency have continued. Park et al [19] proposed a fast algorithm that limits the use of ISP by focusing on the reference samples used for each subpartition block when the ISP is applied. In other words, if a block is not predicted using closer reference samples by ISP, its ISP mode test is skipped to make the encoder faster.…”

“…They measure the CU block texture complexity to determine whether a CU needs to use the ISP mode or not, so as to achieve faster encoding. We note that previous fast ISP decision approaches [19], [20], [21], [22] can reduce the overall encoding time by effectively avoiding unnecessary rate distortion optimization (RDO) processes by fast intra mode decision through characterization of the information of each block. However, we also note that those previous approaches [19], [20], [21], [22] considered only the intra prediction direction and the texture of the block itself; that is, they missed due consideration of the benefit of performing separate transforms for each subpartition.…”

“…Dong et al [22] used decision tree (DT) [37] model for designing a fast ISP mode skip method. But only CU texture complexity is considered as in previous works [19], [20], [21]. While the goal of this paper is to design a fast ISP search scheme (the same goal as previous approaches), the proposed ISP Early Skip Decision (ISP-ESD) scheme also makes early determinations on whether or not to test ISP mode in the RDO process by considering the efficiency facilitated by ISP prediction and transforming each subpartition individually.…”

Complexity Analysis of a Versatile Video Coding Decoder over Embedded Systems and General Purpose Processors

“…Various new features have been adapted to VVC to achieve better coding efficiency [ 5 ]. For example, the largest size of coding tree units (CTUs) is 128 × 128 pixels, quadtree with nested multi-type tree (QTMT) for coding unit (CU) partition, multiple transform selection (MTS) support up to 87 intra coding modes [ 6 ], cross-component linear model, affine motion compensation [ 7 ] and adaptive loop filter (ALF). However, these features come with an increment in computational complexity that has been roughly evaluated as in the encoder and in the decoder [ 8 ].…”