Quality evaluation of long duration AV content--an extended analysis using a novel assessment methodology

This paper is an extension of our previous work describing a novel methodology for quality assessment of long duration audiovisual content. In this article we focus on data analysis of results obtained from two experiments conducted using the new methodology. In the first study, we found that the time dimension does not influence participants' expectations with respect to perceived video quality and that a possible increase or decrease in acceptable quality level is rather directly related to the presented material itself. Moreover, we found that participants are less sensitive to quality changes when the process is controlled externally than when they are in charge of the quality adjustment. A second experiment (study 2) was performed to evaluate the effect of simultaneous quality changes in the two modalities (audio and video) which confirmed the previous results.