LAUSR

We propose a quality control method that replaces rate control in video coding and achieves quality control with the minimum bit rate. First, based on the rate–distortion model, we establish a Karush–Kuhn–Tucker equation considering the convergent properties of variational inequalities to solve the continuous convex problem. Second, combined with the rate–quality (R-Q) model, the proposed algorithm is implemented under versatile video coding (VVC) to obtain the optimal closed-form solution for the quantization parameters of a coding unit through the Lagrange multiplier method. Experiments reveal that our algorithm can achieve stable video coding quality while guaranteeing coding performance, achieving high quality control accuracy with constant quality.