In this paper, we investigate the impact of spatial, temporal and amplitude resolution (STAR) on the perceptual quality of a compressed video. Subjective quality tests were carried out on the TI Zoom2 mobile development platform (MDP). Seven source sequences are included in the tests and for each source sequence we have 32 test configurations generated by JSVM encoder (4 QP levels, 5 spatial resolutions, and 3 temporal resolutions) and a total of 224 processed video sequences (PVSs). Videos coded at different spatial resolutions are displayed at the full screen size of the mobile platform. We report the impact of the spatial resolution (SR), temporal resolution (TR) and quantization stepsize (QS) on the perceptual quality, individually as well as jointly. We found that the impact of SR, TR and QS can each be captured by a function with a single content-dependent parameter. The joint impact of SR, TR and QS can be modeled by the product of these three functions. The complete model correlates well with the subjective ratings with a Pearson Correlation Coefficient (PCC) of 0.99.