Defining user perception of distributed multimedia quality

Abstract

In our study, we explore the human side of the multimedia experience. The authors propose a model that assesses quality variation from three distinct levels: the network-, the media-and the content-levels; and from two views: the technical-and the user-perspective. By facilitating parameter variation at each of the quality levels and from each of the perspectives, we were able to examine their impact on user quality perception. Results show that: a significant reduction in frame rate does not proportionally reduce the user's understanding of the presentation, independent of technical parameters; the type of video clip significantly impacts user information assimilation, user level of enjoyment and user perception of quality; the display type impacts user information assimilation and user perception of quality. Finally, to ensure transfer of informational content, network parameter variation should be adapted; to maintain user enjoyment, video content variation should be adapted. KeywordsQuality of Perception, Distributed Multimedia, Quality, User Perspective Defining Multimedia QualityDistributed multimedia quality is not defined by a "single monotone dimension"; it is judged instead using numerous factors, which have been shown to influence user criteria concerning presentation excellence, e.g. delay or loss of frames, audio clarity, lip synchronisation during speech, as well as the general relationship between visual auditory components [2]. As a result, considerable work has been done looking at different aspects of distributed multimedia video quality at many different levels. Due to these multiple influences, the comparable examination of perceived quality becomes complex. To aid this comparison this paper extends a quality definition model first used by Wikstrand [33] that segregates quality into three discrete levels: the network-level, the media-level and content-level. Wikstrand showed that all factors that influence distributed multimedia quality can be categorised by assessing the information abstraction. The network-level concerns the transfer of data and all quality Defining the Users Perception of Distributed Multimedia QualityGulliver & Ghinea 2 issues related to the flow of data around the network. The media-level concerns quality issues relating to the transference methods used to convert network data to perceptible media information, i.e. the video and audio media. The content-level concerns quality factors that influence how media information is perceived and understood by the end user.• The network-level is concerned with how data is communicated over the network and includes variation and measurement of parameters including: bandwidth, delay, jitter and loss.• The media-level is concerned with how the media is coded for the transport of information over the network and / or whether the user perceives the video as being of good or bad quality. Media-level parameters include: frame rate, bit rate, screen resolution, colour depth and compression techniques.• The content-level is concer...

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