DICE: internet delivery of immersive voice communication for crowded virtual spaces

Abstract

This paper develops a scalable system design for the creation, and delivery over the Internet, of a realistic voice communication service for crowded virtual spaces. Examples of crowded spaces include virtual market places or battlefields in online games. A realistic crowded audio scene including spatial rendering of the voices of surrounding avatars is impractical to deliver over the Internet in a peer-to-peer manner due to access bandwidth limitations and cost. A brute force server model, on the other hand, will face significant computational costs and scalability issues. This paper presents a novel server-based architecture for this service that performs simple operations in the servers (including weighted mixing of audio streams) to cope with access bandwidth restrictions of clients, and uses spatial audio rendering capabilities of the clients to reduce the computational load on the servers. This paper then examines the performance of two components of this architecture: angular clustering and grid summarization. The impact of two factors, namely a high density of avatars and realistic access bandwidth limitations, on the quality and accuracy of the audio scene is then evaluated using simulation results. ABSTRACTThis paper develops a scalable system design for the creation, and delivery over the Internet, of a realistic voice communication service for crowded virtual spaces. Examples of crowded spaces include virtual market places or battlefields in online games. A realistic crowded audio scene including spatial rendering of the voices of surrounding avatars is impractical to deliver over the Internet in a peer-to-peer manner due to access bandwidth limitations and cost. A brute force server model, on the other hand, will face significant computational costs and scalability issues. This paper presents a novel server-based architecture for this service that performs simple operations in the servers (including weighted mixing of audio streams) to cope with access bandwidth restrictions of clients, and uses spatial audio rendering capabilities of the clients to reduce the computational load on the servers. This paper then examines the performance of two components of this architecture: angular clustering and grid summarization. The impact of two factors, namely a high density of avatars and realistic access bandwidth limitations, on the quality and accuracy of the audio scene is then evaluated using simulation results.

Rendering Models for Immersive Voice Communications within Distributed Virtual Environment

“…An example of delivering IVC over server-client architecture is the Dense Immersive Communication Environment (DICE) system described in [10]. In the DICE architecture, the access platforms still perform the auditory scene creation locally but with the assistance of dedicated servers.…”

“…The access bandwidth efficiency of our architecture actually surpasses that of the DICE architecture when applying the HRTF localisation technique with C of only 2 (see C.2 of Section II). If the DICE architecture is to match this performance by setting K to 2, the angular and distance error would be too great to justify (K was actually chosen to be 4) [10]. A major downside of our architecture is that, compared to DICE and the peer-to-peer architectures, more powerful servers are required in our architecture to carry out the auditory scene creations centrally.…”

“…This reuse scheme is based on the concept of "acceptable angular error" ( acceptable ) which refers to the acceptable level of angular deviation between the perceived position and the exact position of a sound source in the virtual world. This concept of acceptable angular error was first proposed in [10] and implemented for a cluster-based computation reduction scheme. In [10] …”

“…This concept of acceptable angular error was first proposed in [10] and implemented for a cluster-based computation reduction scheme. In [10] …”

Cross-tree adjustment for spatialized audio streaming over networked virtual environments

“…In this approach, the central server requires significant computational resources and a large amount of bandwidth to process and disseminate audio streams. To remove the bottleneck at the central server, some proxy-based solutions [7] have been proposed to balance the bandwidth and processing load [3]. The 3D voice provider of Second Life, Vivox, employs a client-server infrastructure.…”