Abstract: A computationally efficient postprocessing technique to reduce compression artifacts in low-bit-rate video coding is proposed in this research. We first formulate the artifact reduction problem as a robust estimation problem. Under this framework, the artifact-free image is obtained by minimizing a cost function that accounts for smoothness constraints as well as image fidelity. Instead of using the traditional approach that applies the gradient descent search for optimization, a set of nonlinear filters is proposed to determine the approximating global minimum to reduce the computational complexity so that real-time postprocessing is possible. We have performed experimental results on the H.263 codec and observed that the proposed method is effective in reducing severe blocking and ringing artifacts, while maintaining a low complexity and a low memory bandwidth.!5
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