'Mean time between failures': A subjectively meaningful video quality metric

As digital communication of television content becomes more pervasive, the long-standing problem of assessing video quality becomes particularly important. This work describes some innovative guidelines for easy and reliable determination of a quality metric that is subjectively meaningful: Mean Time Between Failures (MTBF), representing how often a typical viewer observes a noticeable visual error and a related instantaneous metric relating to the fraction of viewers that find a given video portion to be within acceptable quality levels. The value of MTBF is addressed in the context of video quality, and objective measurements that correlate well with subjective evaluations of MTBF are investigated for different video clips at bit rates in the range of 1.5 - 5 Mbps. The full-reference objective metrics of PSNR and JND are found to have correlation coefficients of 0.69 and 0.88 respectively. In contrast, a reduced-reference objective metric, Spatial Temporal Join Metric [1] (STJM) is found to have a correlation coefficient of 0.84. A method for estimating the MTBF of a video sequence from objective measurements is also described.