A bit-allocation model using on-line rate-distortion optimization in MPEG-4 rate control

In typical video coding, the rate control allocates a target number of bits to each frame and selects the quantization parameters to meet the frame targets. To produce a consistent picture quality between consecutive frames, we propose a new technique for assigning such targets using the Lagrange multiplier method. The proposed bit-allocation algorithm is applied to improve MPEG-4 Q2 rate-control scheme. Simulation results show that the improved Q2 scheme not only achieves 0.42-0.54 dB PSNR gain but maintains a very consistent quality.