Les vidéos omnidirectionnelles, également appelées vidéos sphériques ou vidéos360°, sont des vidéos avec des pixels enregistrés dans toutes les directions de l’espace. Un utilisateur qui regarde un tel contenu avec un Casques de Réalité Virtuelle (CRV) peut sélectionner la partie de la vidéo à afficher, usuellement nommée viewport, en bougeant la tête. Pour se sentir totalement immergé à l’intérieur du contenu, l’utilisateur a besoin de voir au moins 90 viewports par seconde en 4K. Avec les technologies de streaming traditionnelles, fournir une telle qualité nécessiterait un débit de plus de100 Mbit s−1, ce qui est bien trop élevé. Dans cette thèse, je présente mes contributions pour rendre possible le streaming de vidéos omnidirectionnelles hautement immersives sur l’Internet. On peut distinguer six contributions : une proposition d’architecture de streaming viewport adaptatif réutilisant une partie des technologies existantes ; une extension de cette architecture pour des vidéos à six degrés de liberté ; deux études théoriques des vidéos à qualité spatiale non-homogène; un logiciel open source de manipulation des vidéos 360°; et un jeu d’enregistrements de déplacements d’utilisateurs regardant des vidéos 360°. / Omnidirectional videos, also denoted as spherical videos or 360° videos, are videos with pixels recorded from a given viewpoint in every direction of space. A user watching such an omnidirectional content with a Head Mounted Display (HMD) can select the portion of the videoto display, usually denoted as viewport, by moving her head. To feel high immersion inside the content a user needs to see viewport with 4K resolutionand 90 Hz frame rate. With traditional streaming technologies, providing such quality would require a data rate of more than 100 Mbit s−1, which is far too high compared to the median Internet access band width. In this dissertation, I present my contributions to enable the streaming of highly immersive omnidirectional videos on the Internet. We can distinguish six contributions : a viewport-adaptive streaming architecture proposal reusing a part of existing technologies ; an extension of this architecture for videos with six degrees of freedom ; two theoretical studies of videos with non homogeneous spatial quality ; an open-source software for handling 360° videos ; and a dataset of recorded users’ trajectories while watching 360° videos.

Tiling multiple monitors to increase the amount of screen space has become an area of great interest to researchers. While previous research has shown user performance benefits when tiling multiple monitors, little research has analyzed whether much larger high-resolution displays result in better user performance. The work in this paper evaluates user performance on an even larger, twenty-four monitor, high-resolution (96 DPI), high pixel-count (approximately 32 million pixels) display for single-users in both flat and curved forms. The first experiment compares user performance time, accuracy, and mental workload on multi-scale geospatial search, route tracing, and comparison tasks across one, twelve (4x3), and twenty-four (8x3) tiled monitor configurations. Using the same tasks, we evaluated conditions that uniformly curve the twelve and twenty-four monitor displays. Results show that, depending on the task, larger viewport sizes improve performance time with less user frustration. Findings also reveal that curving large displays improves performance time as users interacted with less strenuous physical navigation on the curved conditions. A second study sought to understand why curving the display, effectively bringing all pixels into visible range, improved performance so as to provide guidelines for using such large displays. The study tested for region biases, performance gaps in comparing virtually distant objects, and degree of detail of user insights while measuring the physical navigation required. Results clearly show that significantly less movement is required when physically navigating the curved display. Performance measures reveal that users favor the left regions of the flat display, while there appears to be no region bias on the curved display. Furthermore, user performance time increased as the virtual distance between objects increased, and there is a tradeoff in insight detail between the two forms. In conclusion, larger, high-resolution displays improve user performance, and curving such displays further improves performance, removing any biases towards regions of the display, potentially reducing the performance drop of virtually far apart objects, reducing the amount of physical navigation necessary, and enabling more detailed insights. Based on these findings, one should always curve multiple monitor displays for single users, and if space is an issue, start curving once the display reaches four or five monitors wide. / Master of Science