The Relationship Among Video Quality, Screen Resolution, and Bit Rate

How much bandwidth is required for good quality video for a given screen resolution? Data acquired during two Video Quality Experts Group (VQEG) projects allow at least a partial answer to this question. This international subjective testing produced large amounts of mean opinion score (MOS) data for the screen resolutions QIF, CIF, VGA, and HD; for H.264 and similar modern codecs; and for many bit rates. Those data are assembled in the present report. For each screen resolution, MOS is plotted as a function of bit rate. A plot of all four data sets together shows the bit rate that would be required to achieve a given level of video quality for a given screen resolution. Relations among the four data sets are regular, suggesting that interpolation across screen resolutions might be reasonable. Based on these data, it would be reasonable to choose a bit rate, given a screen resolution; it would not be reasonable to choose a screen resolution given a bit rate.