Sparse shift-DCT spatial prediction

In this paper, we propose a new intra prediction scheme based on hard thresholding applied on shift-DCT coefficients. The explored intra prediction method, validated in an H.264/AVC framework, aims at better predicting complex 2D patterns that cannot be properly extrapolated using H.264/AVC directional intra prediction modes. The basic explored algorithm makes use of neighbor pixels of the current block to predict the current signal using a shift-DCT based extrapolation. Different versions of the algorithm, corresponding to different hard thresholding parameter derivation processes, are described. Experimental results show that the proposed intra coding prediction method can significantly improve the coding efficiency compared to the directional predictive modes of H.264/AVC, with an average BD-rate gain of 6.2% observed on a various pictures test set.