Adaptive linear prediction for block-based lossy image coding

Linear prediction model has been well investigated and applied in lossless image and video coding. In this paper, we investigate the linear prediction method for block-based lossy image coding and propose a method that merges linear prediction technique into H.264/AVC video coding framework. A block-based linear prediction method is designed instead of pixel-based one in order to cooperate with transform module. Furthermore, line-based linear prediction with 1D transform is developed by considering coding gain tradeoff between prediction and transform. Linear prediction model coefficients are derived by using neighboring reconstructed data with least square error method. The model coefficients implicitly embed the local texture characteristics and no bits overhead is needed for signaling the coefficients since we can derive them with same process at decoder side. We insert block-based and line-based linear prediction modes into H.264/AVC as additional intra prediction modes and select the best mode by minimum rate-distortion sense. Experimental results show that the proposed technique improves coding efficiency of H.264/AVC intra picture with average 4.3% bit saving and up to 7.0% bit saving.