An Adaptive Deblocking Filter to Improve the Quality of the HEVC Standard

In this paper, we present an adaptive deblocking filter to improve the video quality for high efficiency video coding (HEVC) scheme. The HEVC standard is a hybrid coding scheme using block-based prediction and transform encoding/decoding. At the decoding step, the boundary of any two adjacent blocks causes visual discontinuities called blocking artifacts that can be removed using deblocking filter. Conventional approaches, including the HEVC standard, tend to remove those artifacts using two offset parameters that are defaulted to 0. However, such a choice is not necessarily suitable to encode/decode all video sequences. The proposed approach reduces an exhaustive search among a set of candidate offsets to eventually select the best offsets adaptively (i.e., for each frame) according to some characteristics of the data sequences. Improvements are shown using the proposed approach in terms of rate- distortion (RD) performance as opposed to the HEVC standard without changing the compression ratio and with negligible change in the encoding/decoding time. Index Terms—Boundary strength, high efficiency video coding, block boundary, deblocking filter.