Dynamic Lists for Efficient Coding of Intra Prediction Modes in the Future Video Coding Standard

The next generation MPEG video coding standard is under development by the Joint Video Coding Experts Team (JVET). This new standard, called Versatile Video Coding (VVC), is expected by the end of 2020 and will offer better coding efficiency than its predecessor High Efficiency Video Coding (HEVC) standard. This coding gain is enabled by new coding tools such as more flexible block partitioning, more accurate Intra/Inter predictions, multiple transforms and adaptive in-loop filtering. In this paper we focus on the coding of the Intra Prediction Modes (IPM) that have been increased from 35 modes in HEVC to 67 modes in VVC. We propose a solution based on genetic algorithms to build an ordered list for the coding of IPM in the Joint Exploration Model (JEM) codec. We first give the theoretical upper bound performance in terms of required bits per IPM to encode the IPM using the available contextual information. The new ordering of the labels associated with more efficient codes is then proposed to efficiently leverage contextual informations available in the encoder and construct the Most Probable Modes (MPM) list. The proposed coding scheme enables to increase the BD-BR performance in average by 0.09% for the same level of complexity compared to the JEM.