In-loop filter using block-based filter control for video coding

In this paper, a method of improving coding efficiency is proposed by using the Wiener filter as an in-loop filter. The Wiener filter can minimize the mean square error between the input image and the decoded image. However, errors of some pixels increase by filtering process. Since the filtered pixels are used for motion-compensated prediction, these errors are propagated to the subsequent images. The proposed method divides the decoded image into some fixed blocks, and decides whether to apply the filter for each block adaptively. As a result, by preventing the increase in errors after the filtering process, the coding efficiency can be improved. Experimental results show that the proposed method achieves bitrate reduction of up to 33.9% in baseline profile and up to 33.0% in high profile at the same PSNR compared to H.264.