Efficient coding of video sequences by non-local in-loop denoising of reference frames

The compression efficiency of coding noisy image sequences is highly dependent on the noise itself and on the used quantization parameter. For very high quality near lossless compression a promising approach to save bitrate is to introduce an in-loop denoising filter in the codec. In this paper, we enhance our in-loop denoising scheme by a low complexity noise variance estimation algorithm. Additionally, we compare three different algorithms for denoising of the reference frame for medium to high quality compression of noisy videos. We use a low complexity adaptive Wiener filter, the NonLocal Means algorithm, and the BM3D algorithm for denoising of the reference frame only. We show that maximum bitrate savings up to 18% can be achieved using a sophisticated algorithm like the BM3D and up to 12% using a low complexity algorithm like the adaptive Wiener filter.