Modeling progressive mesh streaming

Abstract

3D triangular meshes are becoming an increasingly prevalent data type in networked applications such as digital museums, online games, and virtual worlds. In these applications, a 3D mesh is typically coded progressively, yielding a multiresolution representation suitable for streaming. While such progressive coding allows incremental rendering for users while data is being transmitted, it introduces dependencies between data, causing delay in rendering when packets are lost. This article quantitatively analyzes the effects of such dependency by modeling the distribution of decoding time as a function of mesh properties and network parameters. We apply our model to study two extreme cases of dependency in progressive meshes and show that the effect of dependencies on decoded mesh quality diminishes with time. Our model provides the expected decoded mesh quality at the receiver at a given time. Based on this expected value, we propose a packetization strategy that improves the decoded mesh quality during the initial stage of streaming. We validate the accuracy of our model under a variety of network conditions, including bursty losses, fluctuating RTT, and varying sending rate. The values predicted from our model match the measured value reasonably well in all cases except when losses are too bursty.