In this paper, we propose a unified loop filter for highperformance video coding, which suppresses the quantization noise optimally and improves the objective and subjective quality of the reconstructed picture simultaneously. The proposed filter unifies nonlinear enhancement filter (for removing blocking and ringing artifacts) and linear restoration filter (for improving coding efficiency) within the classical optimization framework of least mean square error (LMSE). Experimental results show that the proposed unified loop filter achieves on