Rui Santos Cruz

Personalized Coverage of Large Athletic Events

This article presents a platform that lets users direct their own coverage of large athletic events, letting them set up their own virtual director and orchestrate event viewing according to their preferences.

Quality of Experience Assessment in Internet TV

Nowadays, Service Providers are increasingly concerned about the concept of Quality of Experience (QoE),, even more, when talking about Internet TV or WebTV, where no guarantees of delivery are provided. This paper describes the research and the results on the influence of the level of interest (on a particular sport) in the subjective quality assessment of the corresponding broadcasted media. This analysis is motivated by the work being developed in the European Project My-eDirector 2012, which has the capability to cover the London Olympic Games 2011 via the Web. Therefore, a subjective test was prepared and performed where each observer visioned and assessed the perceived video quality of a set of six sports, encoded in four different bitrate/resolution sets. From the analysis of the collected data it is possible to demonstrate that the interest level has a strong influence in the subjective assessment of the video quality. Based on these results, an empiric formula was deduced to estimate the Mean Opinion Source (MOS) as a function of bitrate and interest level.

Implementing a QoS-aware, context-aware and personalized WebTV

This paper presents the design of a HTTP Adaptive Streaming WebTV Client, featuring smooth media Rate Adaptation, context Personalization, fast program channel switching and Terminal/Network Portability capabilities. The QoS-Awareness during streaming is achieved dynamically by a regulating technique that takes into account network conditions, users device capabilities and the context of viewing. By dynamically optimizing the video quality experienced by the user, the solution provides an excellent streaming application and protocol for heterogeneous network environments.

Push-to-Talk in IMS Mobile Environment

The IP Multimedia Subsystem (IMS), originally designed by 3GPP and later updated by 3GPP, 3GPP2 and TISPAN, presents itself as an architectural framework that allows the convergence of the Internet, wireless and wireline networks and a global platform for the delivery of IP multimedia applications in Next Generation Networks (NGN). One of the most used services to test IMS capabilities is Push-To-Talk (PTT). This service follows the IMS specifications and has motivated standardization work by the Open Mobile Alliance to assure interoperability between different operators. This paper describes a PTT over IMS solution designed with a Talk Burst Control Protocol based on SIP messages for call session control. The implementation was deployed and tested both with high-bandwidth LAN and CDMA2000 wireless network, demonstrating that IMS is a powerful and flexible architecture allowing the quick and easy development of multimedia applications, like PTT, for convergent networks

IPTV architecture for an IMS environment with dynamic QoS adaptation

This paper describes the development, implementation and evaluation of a SIP based IPTV architecture with a new dynamic QoS adaptation method and signaling structure. The implemented QoS adaptation method allows dynamic updates of session parameters, maximizing the QoE and turning the solution suitable for live multimedia streaming, independently of the cast mode (unicast or multicast). The new SIP signaling structure, for session and media control, was developed following an All-SIP approach and a hybrid SIP+RTSP approach, both suited for an IMS environment, in order to compare the system behavior and performance using either approach. The details of both the IPTV Application Server and the IPTV Client prototypical implementations are described, as well as the results of field tests carried out across different Fixed and Mobile access networks for each of the signaling structures. The proposed IPTV architecture revealed to be suitable for scalable converged networks, due to its flexible multimedia delivery of personalized streams over a variety of network infrastructures, namely, Mobile radio networks.

SARACEN: A platform for adaptive, socially aware multimedia distribution over P2P networks

This paper presents the design of a platform for distribution of multimedia content streams supported through innovative techniques, both in terms of media encoding and media distribution. The platform architecture accommodates the use of scalable media coding techniques, including both standard and state of the art research methods (wavelets, multiple description coding), combined with new transport and realtime streaming protocols deployed over peer-to-peer networks. Furthermore, discovery of media resources and selection of peer nodes takes into account social networking related information, as this is available in user communities over the Internet. The design of the platform is taking place in the context of the European FP7 project SARACEN.

Quality aware, adaptive, 3D media distribution over P2P architectures

Recent advances in video distribution over the Internet have inevitably led to the need for accompanying the video related value-added services with the means for maintaining integrity and quality of distributed media to optimize Quality of Experience (QoE). Current systems cover the aspects of maintaining the quality of 2D (only) media by conducting user requirements surveys and 2D QoE assessments. This paper presents the work performed in the EU FP7 SARACEN research project on personalized 3D media streaming over P2P architectures, together with evaluation tests and results as regards scalable and adaptive coding for 3D video streams.