International audienceIn this chapter different factors that may influence Quality of Experience (QoE) in the context of media consumption, networked services, and other electronic communication services and applications, are discussed. QoE can be subject to a range of complex and strongly interrelated factors, falling into three categories: human, system and context influence factors (IFs). With respect to Human IFs, we discuss variant and stable factors that may potentially bear an influence on QoE, either for low-level (bottom-up) or higher-level (top-down) cognitive processing. System IFs are classified into four distinct categories, namely content-, media-, network- and device-related IFs. Finally, the broad category of possible Context IFs is decomposed into factors linked to the physical, temporal, social, economic, task and technical information context. The overview given here illustrates the complexity of QoE and the broad range of aspects that potentially have a major influence on it

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In this paper, we propose a generic framework to human perception analysis in video understanding based on multiple visual cues. Video features that prominently influence human perception, such as motion, contrast, special scenes, and statistical rhythm, are first extracted and modeled. A perception curve that corresponds to human perception change is then constructed from these individual models using linear or priority based fusion approach. As an important application of the perceptive analysis framework, a feasible scheme for video summarization is implemented in order to demonstrate the validity, robustness, and generality of the proposed framework. The frames that correspond to the peak points in these individual models and the fusion curve are extracted as multilevel summarizations that include video keywords, keyframes, and dynamic segments. The subjective evaluations from a supplementary volunteer study on video summarizations indicate that the analysis framework is effective and offer a promising approach to semantic video management, access, and understanding.Index Terms-Multilevel video summarization, perceptive analysis framework, visual multicues, visual perception.

Most existing quality metrics do not take the human attention analysis into account. Attention to particular objects or regions is an important attribute of human vision and perception system in measuring perceived image and video qualities. This paper presents an approach for extracting visual attention regions based on a combination of a bottom-up saliency model and semantic image analysis. The use of PSNR (Peak Signal-to-Noise Ratio) and SSIM (Structural SIMilarity) in extracted attention regions is analyzed for image/video quality assessment, and a novel quality metric is proposed which can exploit the attributes of visual attention information adequately. The experimental results with respect to the subjective measurement demonstrate that the proposed metric outperforms the current methods.