A QoE study of different stream and layout configurations in video conferencing under limited network conditions

One particular problem of QoE research in video conferencing is, that most research in the past concentrated on one-to-one video conferencing or simply video consumption. However, video conferencing with two people (one-to-one) and within a group (multi-party) is different. Particularly, limitations of one participant might have an effect on the QoE of the whole group. This possible effect however is not well studied. Therefore, this paper aims to better understand the impact of individual limitations towards the groups QoE. To do so, we show a study about different video stream configurations and layouts for multi-party conferencing in respect to individual network limitations. For this, we conduct a user study with 20 participants in 5 groups, in a semi-controlled setup. Such a setup, combines supervising participants locally while still using our software infrastructure deployed in the internet. Furthermore, we use an asymmetric experiment design, by putting every participant under a different condition, as this proposes a more realistic scenario. Within our study, we look at three different factors: layout, video quality and network limitations. To foster conversation between participants, the group engaged in a discussion about different survival questions. Our findings show that packet loss and the resulting distortions have a greater impact on the QoE as reducing the video quality by its resolution. Furthermore, our findings indicate that participants are more satisfied in a visually equal layout (showing participants in a similar size) and a more balanced stream configuration

Experiencing virtual reality together: Social VR use case study

As Virtual Reality (VR) applications gain more momentum recently, the social and communication aspects of VR experiences become more relevant. In this paper, we present some initial results of understanding the type of applications and factors that user

Watching videos together in social Virtual Reality: An experimental study on user’s QoE

In this paper, we describe a user study in which pairs of users watch a video trailer and interact with each other, using two social Virtual Reality (sVR) systems, as well as in a face-to-face condition. The sVR systems are: Facebook Spaces, based on puppet-like customized avatars, and a video-based sVR system using photo-realistic virtual user representations. We collect subjective and objective data to analyze users’ Quality of Experience (QoE) and compare their interaction in VR to that observed during the real-life scenario. Our results show that the experience delivered by the video-based sVR system is comparable with real-life settings, while the puppet-based avatars limit the perceived q

TogetherVR: A framework for photorealistic shared media experiences in 360-degree VR

Virtual reality (VR) and 360° video are reshaping the media landscape, creating a fertile business environment. In the past years, many new 360° cameras and VR headsets entered the consumer market. Distribution platforms are being established and new production studios are emerging. VR is a hot topic in research and industry, and many new and exciting interactive VR contents and experiences are emerging. The biggest gap we see in these experiences is the lack of social and shared aspects of VR usage, as today's VR applications tend to be an isolated endeavor. In this paper, we present TogetherVR, a web-based framework for the creation and evaluation of social and shared VR experiences in which users can communicate with a high degree of presence and in photorealistic video quality. We further elaborate on three multiuser VR cases: watching TV together in VR, social collaboration in VR, and social VR conferencing in a mixed reality setting

A QoE Testbed for socially aware video-mediated group communication

Video-Mediated group communication is filtering into everyday use, as commercial products enable people to connect with friends and relatives. Current solutions provide basic support, so that communication can happen, but do they enable conversations? This paper argues that the purpose and the context of the conversation are influential factors that are rarely taken into consideration. The aim should be on the development of underlying mechanisms that can seamless palliate the effects of networking variances (e.g., delays) and optimize media and connection for every single participant. In particular, our interest is on how to improve remote multi-party gatherings by dynamically adjusting network and communication parameters, depending on the ongoing conversation. If we are to provide a software component that can, in real-time, monitor the Quality of Experience (QoE), we would have to carry out extensive experiments under different varying (but controllable) conditions. Unfortunately, there are no tools available that provide us the required fined-grained level of control. This paper reports on our efforts implementing such a testbed. It provides the experiment conductor with the possibility of modifying and monitoring network and media conditions in real-time

The Optimiser: monitoring and improving switching delays in video conferencing

With the growing popularity of video communication systems, more people are using group video chat, rather than only one-to-one video calls. In such multi-party sessions, remote participants compete for the available screen space and bandwidth. A common solution is showing the current speaker prominently. Bandwidth limitations may not allow all streams to be sent at a high resolution at all times, especially with many participants in a call. This can be mitigated by only switching on higher resolutions when they are required. This switching encounters delays due to latency and the properties of encoded video streams. In this paper, we analyse and improve the switching delay of our video conferencing system. Our server-centric system offers a next-generation video chat solution, providing end-to-end video encoding. To evaluate our system we use a testbed that allows us to emulate different network conditions. We measure the video switching delay between three clients, each connected via different network profiles. Our results show that missing Intra-Frames in the transmission has a strong influence on the switching delay. Based on this, we provide an optimization mechanism that improves those delays by resending Intra-Frames

The Service Aware Network: Balancing cost and quality for Social Multimedia Communication

This article explores the notion that a ‘service-aware’ network will help in the cost-effective delivery of social communication between communities, when it is enriched by high quality video and audio. While the concept of dynamically managing network components to balance cost and quality of service is not at all new, the paper explains how future plausible use cases for social multimedia communication prompt four key requirements for a new type of service-aware network. A brief summary is then provided of current research into some of the new capabilities needed to deliver these requirements: Quality of Experience Modelling, Dynamic Network Configuration, and Composition in the Network. Finally, an overview is given of a programme of experiments and trials which are being carried out to demonstrate the applicability and scalability of the service-aware network to real services based on the aforementioned use cases

From IPTV to Synchronous Shared Experiences: Challenges in Design: Distributed Media Synchronization

This paper discusses results from research related to the use of television as a device that supports social interaction between close-knit groups in settings that include more than two locations, each location being potentially equipped with more than one camera. The paper introduces the notion of a framing experience, as a specific scenario or situation within which social communication takes place. It reports on the evaluation of some of the key attributes of social communication through semi-structured interviews, with 16 families across four European countries. The inferences drawn from this study are reduced to four system capabilities including the ability to support: excitement, engagement and entertainment; high quality, reliable audiovisual communications; flexibility and adaptability sufficient to support the unpredictable and reactive nature of human interaction and discourse. These system requirements are, in turn, reduced to a number of technology challenges which if solved will help enable effective social communications between groups, mediated by the television. These technology challenges include: high quality reliable audio visual communication; interaction orchestration, multimedia interpretation and multimedia composition. Finally the paper reflects on the impact the use