Estimating the value of θ in the intra frame for ρ-domain rate control algorithms

The rho-domain rate control algorithm is very simple and effective. There is only one parameter, thetas, used in the model. thetas reflects the relationship between the rate and the quantization step. Accurately estimating the thetas value of the I (intra) frame is important for an efficient rho-domain rate control algorithm because the I frame will influence the remaining frames in the GOP (group of pictures) greatly. In this paper, we propose to estimate the thetas value based on the energy of the frame. The energy difference of the I frames is used to predict the new thetas. A linear relationship between thetas and the energy is deduced. Experimental results show that using the energy can more accurately predict the thetas value of I frame than only using the thetas value of the previous P (predict) frame.