DCT coefficient distribution modeling and quality dependency analysis based frame-level bit allocation for HEVC

A frame-level bit allocation optimization method is proposed to improve the rate-distortion performance for High Efficiency Video Coding. First, to avoid the demerits of the mixture Laplacian distribution model on complexity, a new synthesized Laplacian distribution (SynLD) model is proposed to describe the discrete cosine transform transformed coefficients based on Kullback-Leibler-divergence analysis. Second, quality dependencies among frames are investigated, and a linear relationship between quality dependency factor (QDF) and skipmode percentage is proposed for QDF prediction. Based on the proposed SynLD model and QDF prediction method, a ρ-domain-based frame-level bit allocation method is proposed. Experimental results show that when compared with the state-of-the-art pixel-based unified rate-quantization (URQ) model and R-λ-model-based algorithms, 1.75- and 0.16-dB BD-peak signalto-noise ratio (PSNR) gains can be achieved by the proposed bit allocation method, respectively. For quality consistency, the average PSNR standard deviation shows 0.16 and 0.02 dB lower than URQ and R-λ-model-based algorithms, respectively. The proposed method also has a much more stable buffer control status and works well for scene change cases.