The impact of interactivity on the QoE: A preliminary analysis

The interactivity in multimedia services concerns the input/output process of the user with the system, as well as its cooperativity. It is an important element that affects the overall Quality of Experience (QoE), which may even mask the impact of the quality level of the (audio and visual) signal itself on the overall user perception. This work is a preliminary study aimed at evaluating the weight of the interactivity, which relies on subjective assessments that have been conducted varying the artefacts, genre and interactivity features on video streaming services evaluated by the subjects. Subjective evaluations have been collected from 25 subjects in compliance with ITU-T Recommendation P.910 through single-stimulus Absolute Category Rating (ACR). It resulted that the impact of the interactivity is influenced by the presence of other components, such as presence of buffer starvations and type of content displayed. An objective quality metric able to measure the influence of the interactivity on the QoE has also been defined, which has proved to be highly correlated with subjective results. We concluded that the interactivity feature can be successfully represented by either an additive or a multiplicative component to be added in existing quality metrics.