Laplacian distortion model (LDM) for rate control in video coding

Abstract

In many rate control models, a uniform weighted distortion has been assumed; that is, the DCT coefficients of the motion-compensation difference frames (residues) conform to a uniform distribution. However, the residue after transform does not conform to a uniform distribution but approximate to a Laplacian distribution. In this paper, we first deduce a new distortion model with the assumption of Laplacian distribution of quantized DCT coefficients (called Laplacian distortion model, LDM), and then a more accurate rate-distortion model is proposed based on LDM. Experimental results on H.264/AVC show that our proposed method can improve PSNR up to 0.8dB compared to that of traditional TMN8; meanwhile, the mismatch of target bit rate and actual bit rate generated for coding can be controlled below 2.5%. © Springer-Verlag Berlin Heidelberg 2007.