Fast 2D intra prediction (2DIP) mode decision for image and video coding
A 2D intra prediction with geometrical manipulations (2DIP) was proposed in [1] to enhance the intra coding performance of H.264/AVC. However, the complexity of 2DIP is high if the full search scheme is used. In this work, we investigate ways to speed up the intra prediction mode decision for 2DIP. To achieve this, we first conduct a block correlation analysis that reveals the unique characteristics of 2DIP. Based on the analysis, a fast 2DIP search scheme is proposed to reduce the encoder complexity, where a block classification method is used to identify blocks using LIP only, a good initial search position is predicted and a block pruning technique is introduced. It is shown by experimental results that the fast 2DIP search can reduce the complexity of the full search significantly with little loss in the RD performance.