An Optimal Adaptation Framework for Streaming Multiple Video Objects

With multi-angle video contents available at a user terminal, the user can select his/her preferred alternate views among the given multiple video streams captured at different view angles for a same event. This enhanced experience often entails streaming problems in real-time over the network. In order to cope with this problem, multi-angle video contents are encoded at different bit rates and the appropriate video streams are then selected or transcoded for delivery to meet such bandwidth constraints. Therefore, the selection and transcoding operations become essential processing steps to adapt to the time-varying bandwidth of the network. In this paper, we propose an optimal adaptation framework for streaming multiple video streams by jointly formulating the selection and transcoding problems into a unified optimization problem.

I. Introduction

High-Speed and broadband network services are being popularized in reality and multimedia streaming has become one of the Internet killer applications through such networks. Due to networks with faster and wider bandwidth, it has become possible to provide a multi-angle service with alternate views by delivering multiple video streams. An enhanced video content can be authored with multiple video streams captured at different view angles by their respective cameras. Such a multi-angle service has been addressed in IPTV applications where a viewer can select his/her favorite video streams among alternate video streams for display [1]. This allows the viewer's experience of the broadcast program contents over networks to be enriched. In addition, one of the expected killer applications in TV Anytime is “multiparallel stream linear audio/video programs,” a scenario in which a viewer captures a multistream offering where live multiple cameras are placed in various sporting venues [2]. As shown in Fig. 1, a scene such as a soccer match may be viewed at different view angles by their corresponding cameras. Then, these multiple video streams can be rendered at a client terminal. A goal event could be viewed from the right and left view angles, or from the back of a goalmouth, which would enhance the experience and the reality of the event. Fig. 1.

Concept of a multi-angle video application.