Abstract-HTTP Adaptive Streaming facilitates video streaming to mobile devices connected through heterogeneous networks without the need for a dedicated streaming infrastructure. By splitting different encoded versions of the same video into small segments, clients can continuously decide which segments to download based on available network resources and device characteristics. These encoded versions can, for example, differ in terms of bitrate and spatial or temporal resolution. However, as a result of dynamically selecting video segments, perceived video quality can fluctuate during playback which will impact end-users' Quality of Experience. Subjective studies have already been conducted to assess the influence of video delivery using HTTP Adaptive Streaming to mobile devices. Nevertheless, existing studies are limited to the evaluation of short video sequences in controlled environments. Research has already shown that video duration and assessment environment influence quality perception. Therefore, in this article, we go beyond the traditional ways for subjective quality evaluation by conducting novel experiments on tablet devices in more ecologically valid testing environments using longer duration video sequences. As such, we want to mimic realistic viewing behaviour as much as possible. Our results show that both video content and the range of quality switches significantly influence end-users' rating behaviour. In general, quality level switches are only perceived in high motion sequences or in case switching occurs between high and low quality video segments. Moreover, we also found that video stallings should be avoided during playback at all times.Index Terms-Quality of Experience (QoE), Subjective video quality assessment, HTTP adaptive streaming, Mobile video, Tablet devices.

This paper proposes and tests a theoretical model to investigate the mechanism underpinning local social support exchange via online neighborhood networks (ONNs). We drew on community psychology, social support, and social media literature and used a survey conducted in the Dutch-speaking part of Belgium among 561 ONN users (n females = 409; 72.9%) between 18 and 82 years old (M age = 43.73; SD age = 15.37). We found that engaging in online neighboring behaviors was associated to both online and offline neighborhood sense of community. Subsequently, these provide access to perceived local social support and the intention to mobilize local social support online. The latter was predominantly explained via the path along online sense of community. ONNs facilitate local bridging behavior, connecting otherwise distinct local networks and ties. At the same time, online neighboring behaviors provide the normative context that supports the exchange process.

Lip synchronization is considered a key parameter during interactive communication. In the case of video conferencing and television broadcasting, the differential delay between audio and video should remain below certain thresholds, as recommended by several standardization bodies. However, further research has also shown that these thresholds can be relaxed, depending on the targeted application and use case. In this article, we investigate the influence of lip sync on the ability to perform real-time language interpretation during video conferencing. Furthermore, we are also interested in determining proper lip sync visibility thresholds applicable to this use case. Therefore, we conducted a subjective experiment using expert interpreters, which were required to perform a simultaneous translation, and using non-experts. Our results show that significant differences are obtained when conducting subjective experiments with expert interpreters. As interpreters are primarily focused on performing the si-N. Staelens · N. Vercammen · B. Vermeulen · P. Demeester

PurposeFollowing the outbreak of coronavirus disease 2019 (COVID-19), many forms of bottom-up civic action emerged as ways to collectively “flatten the curve” and tackle the crisis. In this paper, the authors examine to what extent local online and offline social integration contributes to civic participation, above and beyond typical predictors such as news consumption and civic talk.Design/methodology/approachAn online survey was administered among 7,137 users of the online neighbourhood network (ONN) Hoplr in Flanders (i.e. the Dutch-speaking part of Belgium) from 8 May to 18 May 2020. Regression analyses were used to examine how local social integration, in addition to news consumption, civic talk and political antecedents, predict different types of civic participation.FindingsThe results show consistent positive associations between news consumption, civic talk and civic participation during the COVID-19 pandemic. Moreover, the role of political antecedents varied across different forms of civic participation. Further, the results point to the importance of both offline and online local social integration in explaining civic participation.Originality/valueThis study provides much-needed insight in the societal and democratic consequences of the COVID-19 pandemic. The results confirm the importance of local social integration in explaining civic participation, while also advancing theoretical understanding of more established predictors of civic participation, such as news consumption and interpersonal communication.Peer reviewThe peer review history for this article is available at https://publons.com/publon/10.1108/OIR-08-2020-0379.