We present a novel client-driven multi-view video streaming system that allows a user watch 3-D video interactively with significantly reduced bandwidth requirements by transmitting a small number of views selected according to his/her head position. The user's head position is tracked and predicted into the future to select the views that best match the user's current viewing angle dynamically. Prediction of future head positions is needed so that views matching the predicted head positions can be prefetched in order to account for delays due to network transport and stream switching. The system allocates more bandwidth to the selected views in order to render the current viewing angle. Highly compressed, lower quality versions of some other views are also prefetched for concealment if the current user viewpoint differs from the predicted viewpoint. An objective measure based on the abruptness of the head movements and delays in the system is introduced to determine the number of additional lower quality views to be prefetched. The proposed system makes use of multi-view coding (MVC) and scalable video coding (SVC) concepts together to obtain improved compression efficiency while providing flexibility in bandwidth allocation to the selected views. Rate-distortion performance of the proposed system is demonstrated under different experimental conditions.
This paper investigates the influence of the combination of the scalability parameters in scalable video coding (SVC) schemes on the subjective visual quality. We aim at providing guidelines for an adaptation strategy of SVC that can select the optimal scalability options for resource-constrained networks. Extensive subjective tests are conducted by using two different scalable video codecs and high definition contents. The results are analyzed with respect to five dimensions, namely, codec, content, spatial resolution, temporal resolution, and frame quality.
We propose to stream multi-view video over a multi-tree peerto-peer (P2P) network using the NUEPMuT protocol. Each view of the multi-view video is streamed over an independent P2P streaming tree and each peer only contributes upload capacity in a single tree, in order to limit the adverse effects of ungraceful peer departures. Additionally, we introduce a quick join procedure to reduce the start-up delay for the first data packet after a join request. Continuity index and decoded video quality performance for simulcast and MVC encoding in a large topology under different settings are reported, in addition to the improvements achieved by the quick join procedure.
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