At low bit-rates, video coding under the hierarchical prediction structure induces a
temporal distortion known as temporal pumping artifact (TPA) when the quantization
parameter cascading strategy is used. TPA manifests itself as a pumping effect visually, due
to severe quality fluctuations among adjacent pictures, which seriously affects the perceptual
quality of a video. In this work, the causes and perception of the TPA is first
analyzed. Then a metric of just-noticeable temporal pumping artifact (JNTPA) is formulated
based on characteristics of the human visual system. Based on JNTPA, an efficient
algorithm has been devised for TPA reduction (denoted as TRA-JNTPA for short). The
experimental results have demonstrated that the proposed JNTPA measure is in line with
human perception, and compared with JVT-P014, the proposed TRA-JNTPA achieves significant
reduction of the TPA with superior subjective video quality at a given bit-rate.
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