A new MPEG-4 rate control algorithm is proposed to calculate the quantization parameter for given target bit rate. The rate-distortion method models the AC DCT coefficients as Laplacian random variables. Derived from the MPEG-4 variable-length code/run-length code (VLC/ RLC) table, the new model accurately predicts the rates and the distortions of an intra frame for all range of quantization parameters. When compared with the Q2 rate-control algorithm, the proposed algorithm offers better or similar PSNR under lower bit budgets. It also features faster initialization and adaptation to sequence property changes, and meets the target bit rate more accurately than the Q2 algorithm.
['Cheng-Yu Pai', 'William E. Lynch']
MPEG-4 rate control algorithm using Laplace parameter estimation