  To provide users with more realistic visual experiences, videos are
developing in the trends of Ultra High Definition (UHD), High Frame Rate (HFR),
High Dynamic Range (HDR), Wide Color Gammut (WCG) and high clarity. However,
the data amount of videos increases exponentially, which requires high
efficiency video compression for storage and network transmission. Perceptually
optimized video coding aims to maximize compression efficiency by exploiting
visual redundancies. In this paper, we present a broad and systematic survey on
perceptually optimized video coding. Firstly, we present problem formulation
and framework of the perceptually optimized video coding, which includes visual
perception modelling, visual quality assessment and perceptual video coding
optimization. Secondly, recent advances on visual factors, computational
perceptual models and quality assessment models are presented. Thirdly, we
review perceptual video coding optimizations from four key aspects, including
perceptually optimized bit allocation, rate-distortion optimization, transform
and quantization, filtering and enhancement. In each part, problem formulation,
working flow, recent advances, advantages and challenges are presented.
Fourthly, perceptual coding performances of the latest coding standards and
tools are experimentally analyzed. Finally, challenging issues and future
opportunities are identified.
