Efficient Color Artifact Removal Algorithm Based on High-Efficiency Video Coding (HEVC) for High-Dynamic Range Video Sequences

High efficiency video coding (HEVC) has been developed rapidly to support new generation display devices and their ultra high definition (UHD) with high dynamic range (HDR) and wide color gamut (WCG). To support HDR/WCG sequences on the HEVC standard, pre-/post-processing technique has been designed. After an HDR video is compressed, a reconstructed frame exhibits chromatic distortions that resemble color smearing. To remove this color artifact, we herein propose a block-level quantization parameter (QP) offset-control-based efficient compression algorithm for the HDR sequence. First, we extract the candidate coding units (CUs) with the annoying area to the human eye based on the just noticeable distortion (JND) model. Subsequently, the chromatic distorted blocks are verified by the activity function as the chromatic artifact is observed at the nearby strong edge. For the verified artifact blocks, we reassign the QPs for the Cb and Cr chroma components. Our experimental results show that the proposed method yields an average gain in BD-rate of 3.3% for U, and 3.4% for V with a negligible bitrate increase of 0.3% on average.