JND-Based Perceptual Video Coding for 4:4:4 Screen Content Data in HEVC

TL;DR

This paper introduces a JND-based perceptual coding method for HEVC that enhances compression efficiency for 4:4:4 screen content videos by leveraging human visual system models to optimize quantization.

Contribution

It proposes a novel JND-based perceptual coding technique that adjusts quantization at the coding block level, significantly improving compression performance over existing methods.

Findings

Maximum bitrate reduction of 48.3% compared to baseline.

Achieves visually lossless quality at very low bitrates.

Substantially improves perceptual coding efficiency for 4:4:4 screen content videos.

Abstract

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.