Towards prediction of Sense of Presence in immersive audiovisual communications

Tremendous progress has been made in audiovisual technologies in the last decades. Consequently, new technologies quality measures evolve and trend to be more user-centric. This is the reason why the Quality of Experience (QoE) assessment is presently meaningful and challenging, especially for users typical experiences during multimedia content consumption. Such an evaluation is the aim of this paper. More specifically, the Sense of Presence (SoP) was explored in place of QoE as it is a factor influencing the QoE. This paper presents the conducted subjective test investigating typical and practical user experiences. This latter consists of presenting one-minute video stimuli to twenty subjects, on three different devices (iPhone, iPad and UHD screen). Annotated subjective scores were collected and physiological signals (EEG, ECG, and Respiration) were recorded during the conducted subjective test. The resulting multimodal dataset, aiming an alternative evaluation of human experience while consuming multimedia, is publicly available

Measuring quality of omnidirectional high dynamic range content

Although HDR content processing, coding and quality assessment have been largely addressed in the last few years, little to no work has been concentrating on how to assess quality in HDR for 360 or omnidirectional content. This paper is an attempt to answer to various questions in this direction. As a minimum, a new data set for 360 HDR content is proposed and a new methodology is designed to assess subjective quality of HDR 360 content when it is displayed on SDR HMD after applying various tone mapping operators. The results are then analyzed and conclusions are drawn

Towards the Need Satisfaction in Gaming: A comparison of different gaming platforms

Abstract—Recent advances in Virtual Reality (VR) technologies have resulted in a wider availability of Head Mounted Displays (HMDs). However, it is still unclear if VR gaming offers a substantial added value to players. For this reason a comparison of gaming experiences on VR HMD to those on mobile and PC, two other popular gaming platforms, is performed by conducting a user study via two games available on all three platforms. We explore the QoE of gaming by investigating momentous dimensions using the Player Experience of Need Satisfaction (PENS) questionnaire. The results show higher Presence and Autonomy obtained by using HMD when compared to the two other platforms. However, these factors alone did not improve the Overall Quality. To take advantage of the new technology, satisfaction of all psychological needs, especially Competency, must be assured

Multimodal Dataset for Assessment of Quality of Experience in Immersive Multimedia

This paper presents a novel multimodal dataset for the analysis of Quality of Experience (QoE) in emerging immersive multimedia technologies. In particular, the perceived Sense of Presence (SoP) induced by one-minute long video stimuli is explored with respect to content, quality, resolution and sound reproduction, and annotated with subjective scores. Furthermore, a complementary analysis of the acquired physiological signals, such as Electroencephalography (EEG), Electrocardiography (ECG), and respiration is carried out, aiming at an alternative evaluation of human experience while consuming immersive multimedia. Presented results conrm the value of the introduced dataset and its consistency for the purposes of QoE assessment for immersive multimedia. More specically, subjective ratings demonstrate that the created dataset enables distinction between low and high levels of immersiveness, which is also conrmed by a preliminary analysis of recorded physiological signals

Context-based Quality of Experience in Immersive Multimedia

Since 1895, when the Lumière brothers came out with the projected cinematograph, motion pictures and more generally multimedia contents have considerably improved and are still experiencing a very dynamic development. Advances involved improving various modalities that influence the Human Visual System (HVS) or the human perception. Indeed, migrations concerning audio, resolution, color, brightness, depth representations and frame rate have been performed or are being implemented. A high-quality multimedia content targets at least an acceptable level of consumer¿s satisfaction. It assumes to be a combination of sensory stimuli whose goal is to entertain, to educate or to inform, and can convey an artistic intent. Measuring the end-user satisfaction is a challenge as it is a complex multi-dimensional concept. To understand, measure and predict user satisfaction, researchers focused on the perceived quality of multimedia contents. Quality is the expression of an individual comparison and judgment process. It is based on inherent characteristics of a stimulus. It turns out that network-related impairments, major distortions in content delivery, are not considered when evaluating contents¿ inherent features. The quality measure considering the entire service pipeline (including delivery) is referred to as QoS. A more user-centric quality concept has been created under the consideration that not only technical quality and delivery artifacts influence an experience. Accordingly, QoE represents the user¿s degree of delight or annoyance for an application or service in regards to his prior knowledge, expectations and current state. This work addresses the design of new methodologies for QoE subjective evaluation. The research includes identification, definition and investigation on influence factors of QoE. Possibility to predict QoE using physiological signals gathered during subjective assessment is also considered. This thesis is positioned as a framework for the assessment of emerging technologies. Its main focus is on HDR and Wide Color Gamut (WCG) representations, for these emerging technologies provide faithful and realistic content; immersive technologies, such as 360 imaging and VR gaming; as well as the combination of typical multimedia representations (e.g. Standard Resolution (SD), High Definition (HD) and 4K contents along with no audio, stereo and surround audio). From conducted experiments on HDR and WCG, important recommendations came out for these technologies¿ deployment regarding representation and compression strategies while indicating future directions for QoE assessment. We designed a new subjective methodology for 360¿ HDR contents. It investigates which dimensions should be included in immersive and realistic contents evaluation while considering representation constraints (e.g., no spatial pair comparison possible for 360¿ contents). Expectations and novelty effect evaluations, two emerging-technologies-related aspects that can bias QoE-centric subjective assessment, have been implemented in the context of Virtual Reality (VR) gaming. Finally, attempts to predict the SoP, an important QoE-related notion when analyzing physiological signals (brain activity (Electroencephalography (EEG)), heart activity (Electrocardiography (ECG)) and respiration) have been performed for various multimedia consumption scenarios (in terms of quality, resolution and sound systems as well as typical use cases)

Towards an implicit time-continuous assessment of Quality of Experience for immersive multimedia

Quality of Experience (QoE) is a time-varying perceptual process. Despite its complexity and numerous impacting factors, recent efforts have been made to come up with subjective assessment methodologies of QoE. However, no time-continuous variant of subjective evaluation methodologies have been proposed. Considering that an explicit time-continuous assessment could impact the experience itself, validity of conclusions from such an evaluation can be put in question. The solution proposed here is an implicit time-continuous assessment methodology indicating the time-periods of an audio-visual stimulus during which an experience is assessed. The motivation behind this methodology is to provide additional and non-redundant information enabling further investigations in Sense of Presence (SoP). SoP is one of the major metrics in immersive technologies, highly correlated with QoE. This paper describes a work in progress for such an evaluation methodology design

Quality assessment of an HDR dual-layer backward-compatible codec compared to uncompromised SDR and HDR solutions

Broadcasting high dynamic range (HDR) video has been demonstrated as largely preferred when compared to standard dynamic range (SDR), mainly due to its capability of representing more details in dark and bright regions. Additionally, progress over the last decades on creation, compression, transmission and rendering of HDR content signals a forthcoming deployment of HDR broadcasting services. Lack of a widely supported recommendation regarding bandwidth allocation for HDR compressed streams or a unique compression approach, prevent faster deployment of such services. This paper investigates the performance of a dual-layer backward-compatible compression codec, when compared to state-of-the-art HDR compression strategies, in terms of perceived quality. The evaluated system is a dual-layer compression scheme enabling the transmission of a backward-compatible SDR stream along with an HDR stream, reconstructed from the residual-based enhancement layer and SDR mapping (i.e. prediction). Comparison is made to two compression strategies realizing uncompromised SDR or HDR through the use of single layer systems multiplexed with metadata. Metadata contains information necessary to map HDR into SDR or SDR into HDR streams. Our conclusion provides guidance regarding the compression strategy to use as well as bandwidth allocation for HDR delivery, ensuring both SDR and HDR contents with perceptually acceptable quality

Evaluation of ICtCp color space and an Adaptive Reshaper for HDR and WCG

New emerging technologies in the field of multimedia, such as high dynamic range and wide color gamut, challenge the performance of existing image and video data processing algorithms, especially in terms of visual data compression and its faithful representation. High dynamic range and wide color gamut offer to capture and to represent a scene with extended amount of details in both, luminance and chrominance, respectively. This paper presents and evaluates possible solutions to cope with such extended amount of visual information while delivering a faithful representation of visual information. More particularly, two approaches proposing novel color space, a constant intensity color difference signal representation called ICtCp, and novel compression optimization algorithm, reshaper, are described and subjectively evaluated. The results of the conducted experiments show competitive performance of two proposed approaches, ICtCp and reshaper, allowing 10% bitrate reduction while preserving the perceived quality