An accurate rate control for low-delay video communications using lookup tables

The entropy of quantized DCT coefficients has the one parameter—the standard quantization parameter (θ) that is the ratio of quantization step to MAD. We have observed that the coding bits of macro block can be precisely estimated using θ value. Two fixed lookup tables, i.e. θ-table and rate-table is created offline with extensive experiments. Using the two tables, we propose a simple and effective rate control algorithm and implement it in H.263+. Simulation results show that the proposed rate control algorithm outperforms TMN8 in terms of PSNR, buffer steadiness and frame skipped. Meanwhile the computational complexity of our algorithm is very low.