Peer-to-peer interactive 3D media dissemination in networked virtual environments

Abstract

Recent years have witnessed a significant growth in networked virtual environments (NVEs) which are increasingly popular and represent a range of applications. Some online virtual worlds have a dedicated purpose, such asMassively Multiplayer Online Games (MMOG), while others implement more of foundational frameworks which are not necessarily applications per se, but form platforms to create applications. The latter type of NVEs is referred to as metaverses. One of the premier examples of the latter is Second Life from Linden Lab. A significant shortcoming in current NVEs concerns the voice communication between virtual world participants. To enable the creation of an aural soundspace around the user that matches the visual experience, audio streams sent by different speakers cannot be mixed until they reach their destinations. I propose interactive spatial audio dissemination protocols for NVEs in a peer-to-peer (P2P) manner. This type of P2P media dissemination has not yet been significantly investigated, and numerous challenging problems have to be overcome ? among them providing low latency, resilience to churn, effective load balancing and rapid convergence ? in such highly dynamic environ ments.

Additionally, user extensible NVEs/metaverses need an effective way to disseminate massive and dynamic 3D contents (e.g., textures, animations, meshes, etc.) to online users, and at the same time maintain low consumption of server bandwidth. P2P (or peer-assisted) technologies have been widely considered as a desirable complementary solution to efficaciously offload servers in large-scale streaming applications. However, due to both the bandwidth constraints of heterogeneous peers and unpredictable access patterns of latency-sensitive 3D

textures, it is challenging to reduce the server bandwidth consumption in metaverses without degrading the user experiences. In this thesis I investigate the design of P2P-based interactive 3D media dissemination protocols that can satisfy the demanding real-time requirements. Simulation results are presented that show the feasibility and utility of the design, which can achieve near-optimal system reachability (for 3D audio), near-optimal server bandwidth consumption (for 3D textures), and satisfy the tight latency constraints of interactive 3D media under conditions of churn, avatar mobility and heterogeneous user access network bandwidth.