In this paper, we investigate the impact of spatial, temporal and amplituderesolution (STAR) on the perceptual quality of a compressed video. Subjectivequality tests were carried out on a mobile device. Seven source sequences areincluded in the tests and for each source sequence we have 27 testconfigurations generated by JSVM encoder (3 QP levels, 3 spatial resolutions,and 3 temporal resolutions), resulting a total of 189 processed video sequences(PVSs). Videos coded at different spatial resolutions are displayed at the fullscreen size of the mobile platform. Subjective data reveal that the impact ofspatial resolution (SR), temporal resolution (TR) and quantization stepsize(QS) can each be captured by a function with a single content-dependentparameter. The joint impact of SR, TR and QS can be accurately modeled by theproduct of these three functions with only three parameters. We further findthat the quality decay rates with SR and QS, respectively are independent ofTR, and likewise, the decay rate with TR is independent of SR and QS,respectively. However, there is a significant interaction between the effectsof SR and QS. The overall quality model is further validated on five otherdatasets with very high accuracy. The complete model correlates well with thesubjective ratings with a Pearson Correlation Coefficient (PCC) of 0.991.
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