JND-Based Perceptual Video Coding for 4:4:4 Screen Content Data in HEVC
This work addresses perceptual video coding for screen content data, offering incremental improvements in compression efficiency for applications like remote desktop or video streaming.
The paper tackled the lack of perceptual optimization in HEVC's Screen Content Coding extension by proposing a JND-based method that adjusts quantization step sizes using luminance and chrominance masking, resulting in up to 48.3% bitrate reduction and visually lossless coding at low bitrates.
The JCT-VC standardized Screen Content Coding (SCC) extension in the HEVC HM RExt + SCM reference codec offers an impressive coding efficiency performance when compared with HM RExt alone; however, it is not significantly perceptually optimized. For instance, it does not include advanced HVS-based perceptual coding methods, such as JND-based spatiotemporal masking schemes. In this paper, we propose a novel JND-based perceptual video coding technique for HM RExt + SCM. The proposed method is designed to further improve the compression performance of HM RExt + SCM when applied to YCbCr 4:4:4 SC video data. In the proposed technique, luminance masking and chrominance masking are exploited to perceptually adjust the Quantization Step Size (QStep) at the Coding Block (CB) level. Compared with HM RExt 16.10 + SCM 8.0, the proposed method considerably reduces bitrates (Kbps), with a maximum reduction of 48.3%. In addition to this, the subjective evaluations reveal that SC-PAQ achieves visually lossless coding at very low bitrates.